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Rola Shadid BDS MSC AFAAID
Ideal Treatment Plan Sequence
1) The prothesis first is planned 2) The key implant positions and the implant
number are selected 3) The patient force factors are considered to
evaluated the magnitude and type of force 4) The bone density is evaluated in the regions of
the potential implant sites 5) The next consideration is the implant size 6) Implant design 7) Existing bone volume evaluation
bull Mechanical complications are the primary cause of complications after prosthesis delivery
bull Caused by excessive stresses (prosthetic overload)
Stress=ForceArea
Stress
Area
Force
Stress=ForceArea
Five distinct forces factors
1) Magnitude
2) Duration
3) Type
4) Direction
5) Magnification
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Ideal Treatment Plan Sequence
1) The prothesis first is planned 2) The key implant positions and the implant
number are selected 3) The patient force factors are considered to
evaluated the magnitude and type of force 4) The bone density is evaluated in the regions of
the potential implant sites 5) The next consideration is the implant size 6) Implant design 7) Existing bone volume evaluation
bull Mechanical complications are the primary cause of complications after prosthesis delivery
bull Caused by excessive stresses (prosthetic overload)
Stress=ForceArea
Stress
Area
Force
Stress=ForceArea
Five distinct forces factors
1) Magnitude
2) Duration
3) Type
4) Direction
5) Magnification
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Mechanical complications are the primary cause of complications after prosthesis delivery
bull Caused by excessive stresses (prosthetic overload)
Stress=ForceArea
Stress
Area
Force
Stress=ForceArea
Five distinct forces factors
1) Magnitude
2) Duration
3) Type
4) Direction
5) Magnification
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Stress=ForceArea
Stress
Area
Force
Stress=ForceArea
Five distinct forces factors
1) Magnitude
2) Duration
3) Type
4) Direction
5) Magnification
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Five distinct forces factors
1) Magnitude
2) Duration
3) Type
4) Direction
5) Magnification
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Magnitude
The magnitude of bite force varies as a function of
anatomical region and state of dentition (10 to
350 Ib)
The magnitude of force is greater in molar region
less in canine area and least in incisor region
The average bite forces increase with parafunction
(approach 1000 Ib)
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Duration
Under ideal condition the teeth come together during swallowing and eating
( less than 30 minutes) In parafunctional habits teeth may be in
contacts in several hours each day Increase in force duration directly increases
the risk of fatigue damage to cortical bone
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Type
Three type of forces may be imposed on dental implants
o Compression
o Tension
o Shear
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Type bull Bone is strongest when loaded in
compression 30 weaker when subjected to tensile and 65 weaker when loaded in shear
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Type
An attempt should be made to limit tensile amp shear forces on bone
Increased width of implant 1) decrease offset loads
2) Increase the amount of the implant-bone interface placed under compressive loads
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Direction
bull Angled Load
Occlusal load applied to an angled implant body or an angled load (eg premature contact on an angled cusp) applied to an implant body perpendicular to the occlusal plane
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Direction
The implant should be inserted perpendicular to
the curve of wilson and spee
The anatomy of the mandible and maxilla places significant constraints
Bone undercuts further constrain implant placement and thus load direction imposed on the implant
The premaxilla is 12 to 15 degrees off the long
axis of load
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
A 12-degree angled force increases the force to the implant system by 186
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The risks to the bone are increased for two reasons (1) the amount of the stress increases (2) the type of stress is changed to more tensile and shear conditions
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The force applied to an implant body with an angled load is increased in direct relation to the force angle
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
When lateral or angled loads cannot be eliminated
bull Increasing the implant number
bull Increasing diameter
bull Design with greater surface area
bull Splinting the implants together
bull Eliminating all lateral or horizontal loads
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Force Magnification
1) Angled load
2) Poor bone density
3) Parafunction
4) Crown height greater than normal
5) Cantilevered prosthesis
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown Height Space
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown height does not magnify the stress to the implant system when the force is applied in the long axis of the implant body
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull CHS is a vertical cantilever when any lateral or cantilevered load is applied and therefore is also a force magnifier
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The crown height directly increases the effect of an angled force A crown height of 15 mm increases the 21-N lateral force to a 315ndashN-mm moment force
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Torque (moment force)=
Force x Perpendicular distance from the line of force to the center of
rotation
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Greater than 15 mm
Causes long term edentulism genetics
trauma and implant failure
Treatment of excessive CHS before implant
placement includes orthodontic and surgical
methods
Orthodontics in partially edentulous patients
is the method of choice 23
Excessive CHS
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Surgical techniques
block onlay bone grafts
particulate bone grafts with
titanium mesh or barrier
membranes
distraction osteogenesis
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 6-29)
25
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Stress reducing options
1 Shorten cantilever length
2 Minimize offset loads to the buccal or lingual
3 Increase the number of implants
4 Increase the diameters of implants
5 Design implants to maximize the surface area of Implants
6 Fabricate removable restorations that are less retentive and incorporate
soft tissue support
7 Remove the removable restoration during sleeping hours to reduce the
noxious effects of nocturnal Parafunction
8 Splint implants together whether they support a fixed or removable
prosthesis
26
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The greater the CHS the greater number of implants usually required for the prosthesis especially in the presence of other force factors
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Surface Area
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Implant Diameter
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Wide implant defined as a fixture with 45 mm or more in diameter and a lsquonarrowrsquo implant as one in which this was less than 35 mm in diameter
(Renouard and Nisand 2006)
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Advantages of Wide Diameter Implant
The larger diameter implants were primarily
used to improve emergence profile
The wide diameter implant presents surgical
loading and prosthetic advantages
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Surgical Advantages (Surgical Rescue Implant)
Implant not fixated when inserted
Failed implant immediate placement
Tooth extraction immediate placement
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Loading Advantages
Because occlusal stress to the implant interfere at concentrated at the crest of ridge width more important than length
Increased surface area (For each millimeter implant diameter increases
the functional surface area is increased by 30 to 200 depending on the implant design (ie cylinder versus some thread designs)
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Prosthetic Advantages
Improve emergence profile
Decreases the interproximal space
Facilitate oral hygiene
Decrease the need for a prosthetic ridge lap of the crown
The improved contour also allows access to the sulcus for periodontal probing depths
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Prosthetic Advantages
Reducing the magnitude of stress delivered to the various parts of the implant
Decrease force on screw
Minimize component fracture
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Prosthetic Advantages
bull Wide-diameter implants had 58 screw loosening compared with 145 for standard-diameter implants
bull Cho SC 2004
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Prosthetic Advantages
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Disadvantages of Wide Diameter Implants
1) Increased surgical failure rate
2) Decreased facial bone thickness may lead to recession
3) May too close to adjacent tooth
4) Stress shielding the implant is so wide that strain may be too low to maintain bone
39
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Shin et al found an 809 survival rate of 5-mm-diameter wide-bodied implants compared with 968 for the regular-diameter implants over a 5-year period
(Shin SW 2004)
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
What is the Ideal Implant Width
bull Biomechanics
bull Esthetics
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Ideal Implant WidthBiomechanics
The smallest diameter roots
are in the mandibular
anterior region
The canines have a greater
surface area than
premolars because they
receive a lateral loads more
than premolars
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The natural tooth roots are indicator of implant width
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Esthetics Criteria for ideal implant diameter
The diameter of natural teeth in 2 mm below the CEJ is used as a guide to implant body diameter
The implant body diameter should not be as wide as the natural tooth or clinical crown it replaces because this will affect the emergence profile and interdental papilla
Implant should be at least 15mm from the adjacent teeth
Implant should be at least 3 mm from adjacent implant
The faciolingual dimension of bone
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Distance between implants (D)
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Implant-tooth distance
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull The implant dimension in question is the size of the crest module not the implant body dimension (a 41-mm crest module (on a 375-mm implant body) needs 71 mm of mesiodistal crestal bone)
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Multiple anterior implants
When implants are adjacent to each other a minimum distance of 3mm is suggested
The size dimension of two adjacent anterior implants should most often be reduced compared with single implant
The adjacent implants should be splinted together to permit smaller implant diameters to be used without biomechanical complications
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Multiple anterior implants
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Multiple anterior implants
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
When a pontic replaces the lateral incisor the soft tissue drape may be improved compared with an implant
51
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Ideal Implant Diameters
bull The mandibular incisors and the maxillary lateral incisor 3- to 35-mm diameter
bull The maxillary centrals premolars in both arches and canine 4-mm diameter implants
bull The molars 5- or 6-mm diameter
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull In anterior implant should not be wider than 5 mm
bull In the posterior
bull implant should not be greater than 6 mm amp should be at least 4 mm in diameter and the 50- mm diameter is often more appropriate
Ideal Implant Diameters
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Implant Length
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Implant Length Definition According to Literature
bull A dental implant with length of 7 mm or less (Friberg et al 2000)
bull Any implant under 10 mm in length referred to as a lsquolsquoshortrsquorsquo implantrdquo
(Griffin TJ Cheung WS 2004)
bull A device with an intra-bony length of 8 mm
or less (Renouard and Nisand 2006)
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Rationale for longer implant bull The length of the implant is directly related to overall implant surface
area
bull A 10-mm-long cylinder implant increases surface area by approximately 30 over a 7-mm-long implant and has about 20 less surface area than 13-mm-long implants
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Disadvantages of longer implants
Overheating because preparation a longer
osteotomy (D2)
Advanced surgical procedures may be
needed (nerve repositioning and sinus
graft)
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Disadvantages of longer implants
Increase the risk of perforating
lingual cortical plate in anterior
mandible
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Disadvantages of longer implants
bull Excessively long implants do not transfer stress to the apical region (most of the stresses are transmitted within the crestal 7 to 9 mm of bone)
bull Increasing the length beyond a certain dimension may not reduce force transfer proportionately
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Ideal Implant Length
The length of the implant in favorable bone quality and crown height may range from 10 to 15 mm and 12 is usually ideal under most patient force and bone density conditions
bull 15 mm suggested in softer bone types and in immediate placement of long root
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Short Implants
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Rationale for shorter implant
bull Height of posterior existing available bone
Maxillary sinus
Mandibular canal
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull History of Chronic sinusitis
bull Cystic fibrosis
bull Pathological lesions
bull Lack of patientrsquos acceptance for adjunctive surgical procedures to place longer implant
Rationale for shorter implant
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Advantages of Short Implants
1 Stress transfer patterns may be similar between a short and a longer implant
2 Less bone grafting in height Less time for treatment Less cost for treatment Less discomfort
3 Less surgical risk Sinus perforation Paresthesia Osteotomy trauma from heat Damage to adjacent tooth root
4 Surgical ease Decreased inter arch spaces
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Stress transfer patterns to the bone may be similar between a short and a longer implant
Advantages of short implants
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
Previous many studies showed that short and regular implants do not survive equally with increased failure rates for short implants (Herrmann et al 2005 Kotsovilis et al 2009 Balevi 2013 Geckili et al 2013)
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
A systematic review (SR) of the prognosis of short implants in partially edentulous patients showed
bull Short implants (lt 10 millimeters) can be used successfully in patients who are partially edentulous
bull Greater survival rates are associated with implants in the mandible with implants in patients who are nonsmokers and with implants of at least 6 mm in length
Gray et al 2013
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
The available evidence on short implants
bull SR
Short dental implants (lt10 mm) had similar peri-implant marginal bone loss as standard implants (ge10 mm) for implant-supported fixed prostheses
Monje 2014
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
Clinical Implant Dentistry and Related Research 2012
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Implant failures Three early implant
failures
one late failure
Surgical
complications
8 (5 membrane
perforations
2 bleedings 1 sinusitis)
1 (membrane perforation)
Biological
complications
1 (peri-implantitis) 2 (1 peri-implantitis 1
peri-implant mucositis)
Prosthetic
complications
3 (1 abutment loosening
2
ceramic fractures)
3 (1 abutment loosening 1
decementation 1 ceramic
fracture)
Pieri 2012
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
Outcome
measures
Augmented group Short Implants group
Operation time 60 min 30 min
postoperative
pain and
swelling
Increased postoperative
pain and swelling
Three times less pain and
swelling during the first
postoperative week
Marginal bone
loss
difference not statistically
significant
difference not statistically
significant
Implant stability
ISQ
difference not statistically
significant
difference not statistically
significant
Pieri 2012
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
bull Both treatment approaches achieved successful and similar outcomes after 3 years of function
bull Short implants take considerably lower operation
time with decreased surgical complications and postoperative patient discomfort
bull Implant length engaged in alveolar bone does not appear to influence the degree of peri-implant bone resorption after a medium-term period of 3 years
bull More RCTs with longer follow-up times and larger
sample sizes are necessary to validate the current findings Pieri 2012
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
bull Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone
bull Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone
Pistilli R (2013)
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Studies on short dental implants
bull Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster cheaper and associated with less morbidity
bull However data obtained 5 to 10 years after loading are necessary before making reliable recommendations
Pistilli R (2013)
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Esposito M Cochrane Databas Systematic Review 2014
bull There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 85 mm) in reducing prosthesis or implant failure up to one year after loading
bull However there are more complications at sites treated with sinus lift procedures
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Short implant protocol in posterior area
bull Minimize lateral force (anterior guidance)
bull Increase the number of implants supporting the prosthesis
bull Increase diameter
bull Reduce the occlusal width
bull Flatten cuspal inclines
bull Splint together
bull Decrease cantilever length
bull Avoid in bruxers
bull Increase surface area design
( implants with decreased thread pitch)
bull Overdenture versus fixed partial denture in patients with nocturnal parafunction
bull Improve bone density (progressive loading)
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Contributing factors affecting success of short implant
Surgical protocol bull Undersized implant bed preparation
bull lateral bone condensation
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
bull Survival values equal to 95 have been reported for rehabilitation with short implants in partially edentulous and severely resorbed maxillae
bull (Goene et al 2005 Mangano et al 2013) and from
88 to 100 in atrophic mandibles (Stellingsma et al 2004 Anitua et al 2014)
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Conclusion
bull When the ideal implant length is not possible (or practical) a shorter implant with more implant numbers increased width and no cantilever and no lateral forces on the prosthesis is an alternative
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown to Implant Ratio
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown to Implant Ratio
bull In the past several authors empirically established that the maximum crownndashimplant ratio
to avoid overloading should be equal to or less than 11 (Spiekermann 1995 Rangert et al 1997 Glantz amp Nilner 1998)
bull Today several authors have demonstrated that it
is possible to have a crownndashimplant ratio of more than 21 without compromising the short- and long-term outcome of implant prosthetic rehabilitation (Rokni et al 2005 Tawil et al 2006 Blanes et al 2007
Schulte et al 2007 Blanes 2009)
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown to Implant Ratio
Blanes (2009) in a systematic review
bull CI ratios of implant-supported reconstructions do not influence peri-implant crestal bone loss
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown to Implant Ratio
European Association for Osseointegration(2009) indicated the following
bull _ Consensus statement
ldquoRestorations with a CIR up to 2 do not induce peri-implant bone lossrdquo
bull _ Clinical implications
ldquoA FDP or single-tooth restoration with a CIR up to 2 is an acceptable prosthetic optionrdquo
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Crown to Implant Ratio
36-month prospective study Malchiod 2014
bull significant correlation between the CI ratio and the crestal bone loss (CBL) with significantly greater proximal bone loss (PBL) around implants with higher CI ratios than around those with lower CI ratios
bull but no statistical differences were found between short (5 and 7 mm) and longer implants (9 and 12 mm) thus highlighting the fact that it is more important to evaluate the ratio of crown length to implant length than to assess implant length alone
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
Conclusion bull The precise CI ratio that cannot be
exceeded to avoid de-osseointegration or fracture of an implant is unknown
bull it is more important to evaluate CI ratio than to assess implant length alone
bull it is advantageous to reduce forces on restorations with an increased CIR
