Good Morning

BONE GRAFT MATERIALS AND PROCEDURES

AND

FIRST STAGE SURGERYDr Mansi

Contents

• Introduction• History• Definitions• Types of grafts• Successful keys for grafting• Choosing a graft material• Guided tissue regeneration• Membranes

• Maxillary sinus bone grafting• Grafting to improve ridge dimension• Ridge preservation• Immediate implant placement• First stage surgery• Socket Preservation• Conclusion• References

Introduction

• Bone grafting is a dynamic phenomenon. • A successful bone graft…• In their early application, bone grafts were considered a mere

strap lattice. • Today, bone grafts are viewed as biologic structures.

TYPES OF BONE GRAFTS2

• GRAFT (according to GPT) : Tissue or material used to repair a defect or deficiency

Autograft / Homograft Allograft

Isograft Composite grafts

Xenograft / Heterograft Alloplast

HISTORY OF AUTOGENOUS BONE grafts fgraGRAFTING1

ALLOGENIC BONE GRAFTING History:

Bone induction principle was described by Urist for allogenic bone in 1953

Urist and Burwell in 1968 and later in 1969 gave the use of allogenic bone either fresh or frozen and dried.

Urist in 1968 also described that allogenic bone is replaced by new host bone.

Indications for Bone Grafting 2

Ø     Jaw resection following malignancy / other pathology Ø     Extensive trauma Ø     In orthognathic surgery Ø     As an onlay material in facial aesthetic surgeryØ     Large bony defects created by cysts and tumorsØ     In preprosthetic surgery as an onlay, fill materialØ     In cleft patients.Ø     In implantology e.g. : sinus lift procedure Ø     In periodontal surgery

Objectives Of Bone Grafting (Schallhorn, 1977)

• Pocket reduction/Elimination• Gain in clinical attachment

• Restoration of host alveolar bone• Regeneration of new bone, cementum & periodontal ligament

• To establish a healthy maintainable environment

Characteristics of Ideal Bone Graft Materials, Boyne in 1973

– Should be readily available and not require surgical intervention at a second donor site.

– Should provide rapid osteogenesis.– Should not elicit immunological responses.– Should enhance revascularization.– Should be highly osteoinductive.– Should provide for osteoconduction.– Should provide for the formation of new attachment in periodontal

lesions.– Should not impede bone growth.

Advantages Of Bone Grafts

• Regeneration of the attachment apparatus is possible.• It is possible to reverse the disease process.• Increased tooth support, improved function, and enhanced esthetics. • All categories of intra osseous defect and certain furcation defects. • Idealistic therapeutic objectives may be achievable

• Disadvantages of bone grafts (Mellonig 1992)• Increases treatment time.• Autografts require two sites.• Increased postoperative care.• Bone grafts take a long time to heal.• Need for multiple therapy-secondary surgeries.• Availability & the added expense of graft material.• Technique sensitive.

Physiologic considerations and process , graft materials can be divided as3:• Osteoinduction: is the induction of bone formation in the

absence of a bony host site. • Eg. Certain bone morphogenic proteins refined…

• Osteostimulation: is a physiologic action that stimulates, enhances or accelerates the formation of bone at a host

site or healing endosteal implant. • Eg, recombinant bone morphogenic protein, platelet rich

plasma.

• Osteoconduction: is the process in which synthetic and inorganic material provides a bioinert scaffolding that

conducts and is compatible with bone growth. • In general alloplastic graft materials are osteoconductive.

• Osteopromotive: Physical means of sealing off an anatomical site in order to prevent other tissues to interfere

with osteogenesis and to direct the bone formation.

• Osteogenesis: occurs when living osteoblasts are part of the bone graft as in autogenous bone transplantation.

Biologic properties of various bone graft materials (caranza chapter 77)2

Source Osteoconductive osteoinductive Osteogenic

Alloplast Yes No No

Xenograft Yes No No

Allograft Yes Yes/No No

Autograft Yes yes Yes

II] Conge et al. (1978) CLASSIFIED AS

Osseous Non-Osseous

Autografts

Allografts

PedicleBone

swaging

Free grafts

IntraoralBone

coagulumBone blendTuberosity

Extraction sitesEdentulous

ridge

ExtraoralIliac crest

Tibia

OrganicCollagenDentin

CementumCoralSclera

Cartilage

Inorganic (Alloplasts)

POPPolymers

Ca carbonatesCeramics

Human bone FDBADFDBA

ResorbableTCP, HA

Non-ResorbableHA, Bioglass

Xenografts

FORMS OF BONE GRAFT

• 1.        Non-vascularised • 2.        Vascularised • 3.        Cancellous • 4.        Cortical • 5.        Corticocancellous, has properties of both types

Cortical bone Cancellous boneCortical bone grafts revascularise slowly.

Vascularise within 2 weeks

There is viable and non viable bone Here only new bone remains and the necrotic bone is removed. Here we have only viable bone.

This bone graft decreases in mass and in porosity

Initial increase in strength, in time mechanical strength return to normal due to osteoclastic activity and decreased osteoblastic activity

Cortical bone contains pure cortex dense bone,hence it is used for weight bearing areas.  

Cancellous bone provides more open spaces for faster revascularisation, but it lacks mechanical strength, particularly when used for non weight bearing areas.

I Autograft

• This refers to bone tissue transferred from one site to another in same individual.

• Common sources of bone include:– healing extraction wound– edentulous ridges– trephined from within the jaw– Newly formed bone in the wounds– osteoplasty and osteotomy

• Clinically these grafts can be further classified on the basis of

• SITE OF ORIGIN • Ø     Iliac, fibula, rib

• Ø     Intraoral sites(caranza)2

• PHYSICAL FORM • Ø     Paste, Morsel, Chip, strip,

block, segment, match stick

Osseous Coagulum

• R. Earl Robinson in 1969• A mixture of bone dust and blood.Source: Mandibular lingual ridge, exostosis, edentulous ridge, distal

terminal tooth etc.Advantages:

– smaller particle size– additional surface area– Ease of obtaining bone from already exposed surgical sites.

• Disadvantages:– The unknown quantity, inability to aspirate, contamination

Bone Blend

• Introduced by Bowers in 1972.• Cortical and Cancellous bone is procured with a trephine or rongeurs • Autoclaved amalgam capsule is used for the purpose of blending ,Slushy

osseous mass (210 – 105 um) packed into bony defects

• BONE SWAGING• This technique requires an edentulous area adjacent to the defect, form where the bone is pushed into contact with the root surface without fracturing the bone at its base.

Elasticity of bone…

Platelet rich plasma:

• This autogeneous material is sequestrated from patient’s blood and compacted by gradient density centrifugation.

• It substantially increases the rate of healing. Histologically, they have revealed greater bone density after healing.

• Role- increase in bone forming cells• Trigger capillary formation• Increased site debridement• Source of growth factor’s

Allografts

• Allograft or alloimplant refers to bone which is harvested from one individual and transplanted into another within same species.

• These bone tissue implants provide the form and matrix of bone tissue, but no viable bone cells are transplanted.

• They are of three types:– Mineralized freeze-dried bone allograft (FDBA)– Demineralized freeze-dried bone allograft (DFDBA)– Frozen iliac cancellous bone & marrow

Freeze dried bone allograft FDBA

• It is a human bone, harvested from fresh cadavers• It is then sterilized,freezed and dried .

• It works primarily through conduction, thus over a period, it will resorb and bone graft is replaced.

• Used in sinus bone grafting procedures.

• Process of making: 2 Bone is washed in distilled water and ground to particle size of 500 mic to 5mm.It is then immersed in nitrogen then

freeze dried, and ground to small particles( 250 – 1500 mic)

Demineralized freeze-dried bone allograft(DFDBA)

• Created by removing the ca and po4 salts to take better advantage of BMP for its osteostimulatory properties.

• Process of fabrication: similar initial steps as FDBA but an additional step of demineralizing the ground bone powder in

0.6N HCL or nitric acid for 6-16 hrs.

• Freeze drying destroys all cells and the graft is rendered non viable.

–It has the advantages of:»Decreasing antigenicity

»Facilitating long term storage

III Xenografts 3

• Two available source:– Bovine bone – Natural coral

• Calf bone (Boplant)• Kiel bone• Anorganic bone

• Bio-Oss ® Granules, Bio-Oss ® Collagen, and Bio-Oss ® Blocks, Endobone® ,Ladec® , Bon-Apatite®, OsteoGuide TM (Anorganic Bone Mineral), OsteoGuide Collagen TM (Anorganic Bone Mineral with Collagen),Osteograf/N.

IV Synthetic bone grafts/ Alloplasts2

CLASSIFICATION

POLYMERSBIOLOGI C

collagenfibrin

SYNTHETIC Polylactic polyglycolic acid polymers

• Bioactive Glass– Calcium salts, Phosphates- similar to teeth, bone – Sodium and silicon dioxide- bone to mineralize– Mechanism of Action: – When it comes in contact with tissue fluids-– Particle surface gets coated with hydroxycarbon apatite-– Incorporates organic ground proteins like chondroitin sulphate

and GAGs – Attracts osteoblasts – rapidly form bone.– Bonds with bone and soft connective tissue

 

HYDROXYAPATITE 2

• This is a mineral substance, basically a ceramic which is similar to cortical bone in its composition.

• It is inorganic, stable, non absorbable and non biodegradable.

• They are osteoconductive …• Three types dense, porous and resorbable.

CALCIUM SULPHATE2

Plaster of Paris:POP (Calcium sulphate) is biocompatible and porous,thereby allowing fluid exchange, which prevents flap necrosis.• POP resorbs completely in 30 daysThis material can be carved into the desired shape…

• ACRYLIC RESINS • A two component system• Uses include dental implants, submucosal augmentation, contour

correction.• Difficulty in handling ,Problems with thermal, electrical and X-ray

conductivity.

SILICONE RUBBER • Biocompatibility and excellent physical characteristics.• Thermal stability•  Basic building block is dimethylsiloxane with contributions from

other organic side…   • Disadvantages include low tear resistance

• POLYETHENES and POLYTETRAFLUROETHYLENE (TEFLON)-    Group of polymers made from ethane type monomers and include

polyethylene and polypropylene.•  Porous sponge form can be used in reconstruction in non load bearing

areas.   

• POLYURETHANES • POLYAMIDE

Collagen2:

• Most common source is bovine collagen from the Achilles tendons in the leg.

• It can bond and activate platelets to form a platelet plug within the vessel.

• It may also act as a scaffold for migrating cells of the epithelium

•     Polycrystalline ceramics, and either in porous or dense forms. - Capo ceramics-These are are hard tissue prosthetic materials that

interact with and may ultimately become an integral part of living bone.

Limitation : • - Brittle, low impact resistance and relatively low strength. • Advantages: Biocompatible Lack of local systemic toxicity. They bond directly to bone

without the need for porosity.

CALCIUM PHOSPHATE CERAMICS

Particulate bone graft:2

• Also called bone chips• Advantages : more rapid ingrowth of blood vessels• More exposure of osteooinductive growth factors• Easier biologic remodeling• Indications:• In defects with multiple osseous walls • In dehiscence or fenestration defects• If a bone defect does not have a osseous wall to contain the graft 

Monocortical block Graft:2

• Horizontal alveolar deficiencies can be best treated by it• The technique uses a cortical block of bone harvested from

a remote site and used to increase the width of bone.• Intraoral sites- mandibular symphysis or ramus• Extraoral sites- iliac crest or tibia.• It is fixated to the prepared site with screws. 

• A study was done to identify which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement.

• A systematic online review of a main database and manual search of relevant articles.

• Implant survival was 92% for implants placed into autogenous and

autogenous/composite grafts,

Int J Oral Maxillofac Implants. 2008 Jan-Feb;23(1):56)

Surgical keys to bone grafting:2

Local factors: • absence of infection• soft tissue closure• space maintenance• graft immobilization• host bone vascularization• Growth factors• bone morphogenic proteins• healing time • defect size and topography• transitional prosthesis

Successful Graft: Mellonig JT (1991) 7

• A) Patient Selection:• B) Material Selection:

– More walls of bone -in the defect site- better a graft’s chance for success

– Larger the defect -use autogenous bone – Cancellous bone over cortical bone - revascularization is rapid. – GTR membrane is not necessary for autogenous graft -but in non-

autogenous revascularization occurs slowly so GTR membrane is helpful.

• C) Proper flap reflection and wound stability:– Conventional full thickness – Alternative design-coronarlly repositioned flap.

• D) Revascularization:– Underlying bone that receives the graft material must exhibit several

marrow spaces

• E) Root debridement: – Remove completely the altered cementum and other deposits

• F) Post-surgical Care:– Antibiotics – Mouthwash and oral hygiene maintenance – Periodic recall visits and regular plaque controls  

Soft tissue coverage and flap design2

1)Primary soft tissue closure is a mandatory condition for the success of grafting procedures .

2)Primary incision- keratinized tissue 3) The blood supply to the reflected flap-maintained 4)Soft tissue flap design should have the margins of the wound over

host bone rather than on the graft or barrier membrane 5)Primary wound closure should be without tension 6)The margins distal to the elevated flap should have minimal

reflection 

Choosing a graft material:

• Five wall defects-• Four wall defects-.• Three wall defects- allogenic bone blocks around the margins,or

allogenic putty.• Two wall defects- particulate autogenous bone graft with a

barrier membrane secured in place with pins or screws. • One wall defects- referred to as knife edge defects and require a

two stage treatment with bone grafting techniques.

Alloplasts are used

The classification of bone defects: (Lindhe)

• Class I – Extraction sockets• A flap is raised to allow easy access to the site and implant

inserted• A membrane supporting material is adapted to support the

membrane• It is placed into the space between the walls of the socket and

implant surface.• Subsequently the membrane is adapted to cover the supporting

material and a narrow zone of the adjacent bone and the flap is adapted and sutured. 

• Class II and III – Dehisence defects • Procedure:• After the flap is raised the implant is inserted.• A membrane is placed and adapted to cover the supporting

material and the defect.• The membrane is to be fixed in place to provide stability

necessary for bone to form.• Implant is allowed for submerged or transmucosal healing.

• Class IV- Horizontal defects.

The autogenous block transplant-the gold standard(Becker et al 1994)

Disadvantages of intraoral harvesting procedures: • limited availability of bone graft volume, • complications including altered sensations• wound dehiscence• infection

Advantages: • large scientific and clinical documentation • handling properties,

Class V- Vertical Defects

• Include situations where the remaining bone height is too small… • The same procedure as for IV with the exception that the bone block

is partially or fully placed on the ridge in order to gain bone in a vertical direction.

• Flap adaptation is more difficult due to increased volume intended for regeneration which intends to be covered by the flap.

Guided tissue regeneration5:

• The terms ‘‘guided bone regeneration’’ and ‘‘guided tissue regeneration’’ (GTR) often are used synonymously and rather inappropriately.

• GTR deals with the regeneration of the supporting periodontal apparatus, including cementum, periodontal ligament, and alveolar bone,

• Whereas GBR refers to the promotion of bone formation • Principle that use barrier membranes for space maintenance over a

defect, promoting the ingrowth of osteogenic cells and preventing migration of undesired cells from the overlying soft tissues into the wound.

Bone Augmentation Techniques;J Periodontol • March 2007, McAllister, Haghighat

Graft + GTR Membrane

The use of physical barriers to retard or prevent apical migration of epithelium as well as exclude gingival connective tissue from the the healing wound form the basis of GTR(Gottlow et al 1986)

Guided bone regeneration5: • Defects associated with dental implants may be divided into several

categories:• For isolated localized defects or defects associated with implant

placement• Dehiscence defects- most common. Defect of cortical bone resulting

from trauma, bone resoption or tooth removal• Residual intraosseous defects- incomplete healing of the alveolus

leading to exposure of threads• Fenestration defects- anterior maxilla• Extraction socket defects 

Membranes5:

• Criteria regarding membranes have been formulated(Hardwick et al 1994)5

• Biocompatibility• cell occlusiveness• intergration by host tissues• clinical manageability• space making function• Additional criteria for bioresorable and biodegradable are (Gottlow

1993)• tissue reactions should be minimal• these reactions should be reversible• they should not negatively influence the regeneration of the desired

tissues.

Nonresorbable membranes

• Polytetrafluoroetylene (PTFE), Expanded PTFE(e-PTFE or teflon), Titanium-reinforced membranes

Expanded PTFE is characterized as a polymer with high stability in biologic systems…

• They are available in various sizes and shapes to custom fit around teeth and osseous defects.2

• Adv2: 1. Ability to maintain separation of tissues • Unless exposed it can remain in place for several months to

years.• Disadv2: 1. If it becomes exposed it will not heal

• Bioresorbable membranes2,3

• ePTFE materials is that they are non-resorbable and therefore have to be removed during a second surgical procedure.

• Made of either collagen or polyglycolide and/or polylactic acid. Advantages• No need for membrane removal surgery• Better cost-effectiveness• Decreased patient morbidityDisadvantages• Uncontrolled duration of barrier function• Resorption process possibly interfering with wound healing and bone regeneration• Mild inflammatory reaction may interfere with osteogenesis• Are quite piable- collapse into the defect area.

Bone augmentation by means of barrier membranesChristoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33, 2003, 36–53

• Various reasons for the generally lower defect fill with bioresorbable membranes as compared to nonbioresorbable membranes include:

• the better space-making capacity of nonbioresorbable;• controlled time of barrier function;• lack of a resorption process and lack of the generation of resorption

products that negatively affect bone formation;• longer experience with nonbioresorbable membranes

In summary, the nonbioresorbable membranes allow for slightly more bone regeneration than bioresorbable ones.

Bone augmentation by means of barrier membranesChristoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33, 2003, 36–53

Maxillary sinus bone grafting10

• Tantum was first to perform sinus augmentation in mid 1970’s.• Boyne and james were the first to report their 4-yr experience with

autogeneous bone placed in the sinus.

• Assessment of maxillary bone Parel classification10

• Class I: Alveolar bone height normal – patient with missing only teeth alveolus is intact. Best treated with a fixed prosthesis or requires an alveolectomy or osteotomy to create room for a removable prosthesis.

• Class II: Moderate alveolar bone resorption- patient needs restoration of alveolus either with denture flange or bone graft.

• Class III: Severe alveolar bone resorption- all alveolar bone resorbed, patient requires restoration with denture material or bone graft. Patient needs extensive grafting to provide a stable prosthesis mechanically.

Misch treatment options:12

• Subantral option one: Conventional implant placement• When sufficient bone height is available to permit the placement of implant following a usual surgical protocol. The quality of bone

commonly is D3 or D4 bone, bone compaction to prepare the site is common.

• Subantral option two: sinus lift and simultaneous implant placement

• When 10 to 12mm of vertical bone is present (2mm less than SA-1). The antral floor is elevated through the implant osteotomy 0 to 2mm, it modifies the floor of the maxillary sinus.

• Subantral option three: Sinus graft with immediate or delayed endosteal implant placementIs indicated when less than 5mm of vertical bone and sufficient width

are present between the antral floor and the crest of the ridge. • The author has chosen residual height of 5mm because:Can be considered sufficient to allow primary stability placed at the

same time of sinus graft procedureMay allow the use of alloplastic materials because adequate

amounts of bone may be harvested from the tuberosity • Subantral option four: sinus graft healing and extended delay

of implant insertion• When less than 5mm remains between the crest and floor of sinus.

Direct sinus lift procedure

• The sinus surgery is done first. • Design of the incision depends upon the width of the attached gingiva.• After the membrane is elevated and the lateral maxillary wall rotated

medially, the thickness of the alveolus is accessed and the proper bone graft can be harvested

• After the lateral maxillary wall is exposed a 3mm diameter round bur or no.8 round diamond stone in high speed impactair handpiece,

• Make a horizontal line parallel to and at the level of the antral floor in the lateral cortex of the maxilla.

• Create the groove by gentle brushing of the bone so that it barely penetrates the cortical plate

• As this is done the superior line with its remaining attachment to the flap becomes a hinge.

• After the door is pressed inward for 4 to 5 mm, reflect the membrane from the bony floor of the sinus.

• If the sinus floor is thin(1-2mm)…• Bone harvesting

Grafting to improve ridge dimension for the accomadation of implantsAnterior mandible width deficiencies11:

• Alveoplasty: knife edged ridges or sharp spicules can be removed before making implant osteotomies..

• Monocortical bone grafting: affixing a block of bone can augment the width and height of the anterior mandibular ridge.

• This may be obtained from a bank or can be autogeneous bone, mandibular symphsis being the ideal site.

• The graft is stabilised in place with titanium screws. 

• Anterior mandible height deficiencies:• Monocortical grafts• Inferior border augmentation:• If a patient has extremely atrophied mandible(1 to 6mm thick).

Autogeneous bone from iliac crest is taken.• A mesh prosthesis with graft material is affixed to inferior border with self

tapping screws. An titanium inferior border mortise-form mesh is filled with iliac crest marrow and is harvested.

• Posterior mandibular height and width deficiencies:

• Monocortical bone grafting: symphyseal monocortical block inlays may be used in regions posterior to mental foramina.

 Mandibular neuroplasty and nerve management:• To add additional vertical height: make an incision at the crest of the

ridge from the retromolar pad anteriorly to most distal tooth in position. Use a sponge to elevate the mucoperiosteum to the level of the mental foramen.

Anterior maxillary width deficiencies:

• Monocortical bone grafting• Expansion by longitudinal splitting: Make a crestal incision and reflect the

mucoperiosteum. Refine the lower border of the ridge with a ronguer and bone files and allow the entry of first no.1/2 round and then no.699 high speed bur. Make perforations using these bur to the full depth and connect them into a groove, this is followed by placement of spatula osteotome into the osteotomy.

Bone Augmentation Techniques ,J Periodontol • March 2007, vol 78;3:386 McAllister, Haghighat

A staged ridge-expansion technique. Vertical and horizontal corticotomies are made, following a partial-thickness flap elevation, a conventional ridge-expansion is performed. A saggital saw is used to perform the crestal corticotomy. Uncovery at 6 months was done following the placement of the implant.

Anterior maxillary height deficiencies:

• 1. Block grafting

• 2.Nasal floor elevation: The pyriform apertures can be exposed by means of an intraoral approach.

• The floor of the nose either unilaterally or bilaterally may be grafted for upto 10mm so that apical extensions of implants of sufficient length can be enclosed in bone with only modest impingement of the nasal floor.

Immediate implant placement (BDJ 2006.201;4:199)

• While extraction, care must be exercised not to luxate the tooth buccal- lingual..

• A direction indicator should be used to verify the correct angulation and trajectory of the proposed implant.

• The benefits of immediate placement are11:• Combining integration of the implant with mineralization of the

socket shortens healing time.• Preservation of ridge morphology and dimension is encouraged

by the presence of an implant• Position and angulation of the implant is simpler because the

recently removed tooth indicates this geometry and the walls of the alveolus serves as guides in directing the osteotomy.

SOCKET PRESERVATION:

• It implies that placement of varying implantable materials within the sockets alone or with barrier membranes maintains socket anatomy.

• Ridge width and height dimensions were preserved with bone graft materials.

• The study suggests that treatment of extraction sites with membranes made of glycolide and lactide polymers is valuable in preserving alveolar bone in extraction sockets, minimize crestal bone loss and preventing ridge defects.14

 To preserve the extraction socket architecture and to accelerate the timeline to final implant restoration, the technique of immediate implant placement at the time of extraction often is proposed.

         

FIRST STAGE SURGERY8

• A surgical splint can be used to determine proposed fixture locations and serve as a guide.

• The first stage surgery consists of following events (Adell et al 1981,1985; Albrektsson et al., 1986; Lekholm,1983) and Surgical technique for implant installation( BDJ OCT 1999, 187; 8: 415)9 :

1. Anatomical consideration2. Surgical incision of gingival and mucoperiosteal flap reflection3. Drilling and countersinking procedure4. Tapping procedure5. Fixture installation and cover screw placement6. Implant placement 7. Soft tissue re- adaptation and suture procedure

1.Anatomical considerations:

• Fully conversant with all anatomical structures that they are likely to encounter

• In the maxilla: air sinuses, nasopalatine canal, floor of nose and nasal spine, palatine and pterygoid vessels.

• In the mandible: sublingual vessels, mental nerve, inferior dental nerve, incisive branch of inferior dental nerve, genial tubercles.

• Teeth: position, length, angulation of roots adjacent to implant sites.

• Available bone: ridge morphology, bone density, localized deformities

2. Surgical incision of gingival and mucoperiosteal flap reflection

• Make the surgical incision with a no.15 blade and cut through mucosal tissue along the same line.

• Dissect the muscle fibres carefully with the no.15 blade• The periosteum is cut carefully 5mm below the crestal ridge ,When

incision is difficult, lengthen the incision into the periosteum toward the alveolar crest.

• Expose the alveolar crest using the dissector to remove any fibrous adhesions.

• Locate any anatomical landmarks or foramen if any.

• Flap design: There are many different flap designs for implant surgery.

• In practically all situations a mid-crestal incision can be employed. Access and elevation of flaps can usually be improved by additional use of vertical releasing incisions.

3.  Drilling and Countersinking procedures• Guide drill• Use of any of the drilling instruments requires copious saline irrigation. • Use the guide drill to mark the proposed fixture sites and

penetrate the cortical plate into spongy bone.

 • Use of 2mm twist drill• It is used to enlarged the fixture site. Each fixture site is marked using the guide drill and enlarged sequentially with 2mm twist

drill.• A direction indicator into the prepared site. At this stage the direction

of the fixture site can be changed using the guide drill and side cutting drills.

• Use of pilot drill

• It is used to enlarge the site from 2-3mm diameter. Do not exceed the mark on the pilot drill indicating depth since it may result in thermal damage. 

• Inferior aspect- engage the 2mm prepared site and superior portion begins the enlargement of the site. 18

Use of 3mm twist drill • This procedure is important for preparing the fixture site to the proper depth.• Used to prepare the bone to its final dimensions.

• Use of countersink • It is done after enlarging the site to 3mm to achieve fixture and cover height level with the alveolar bone. Used to create a shelf in the prepared bony site.Crestal module…

Surgical preparation of the bone

• It is essential not to allow the bone to be heated above 47deg cent during preparation as this will cause bone cell death and prevent osseointegration.

• This problem may be avoided by:• Using sharp drills• Employing incremental drilling procedure with increasing diameter drills• Avoidance of excessive speed (no more than 2000rpm) and pressure on

the drills- it should be withdrawn from the bone frequently to allow the bone swarf to clear

• Using copious sterile saline irrigation.

4.Tapping procedure

• It is first in series of slow speed bone preparation instruments• It is utilized to thread the bone prior to implant placement• In harder bone type tapping is done, using the slow speed

handpiece or use the cylinder wrench to tap manually

Number of drills used to prepare implant osteotomycorresponds to bone density, Carl E Misch • D1 bone- requires 4 drills, a crestal bone drill and

a tap

•D2 bone- standard drill protocol is used

•D3-requires only 3 drills and no crestal drill or tap•D4- requires 2 drills and osteotomes to compress the residual bone making it more dense

5.Fixture installation and cover screw placement

• A fixture mount is connected to the fixture using the open ended wrench and long screwdriver.

• The fixture mount is connected to handpiece the implant is installed without irrigation until the horizontal hole of the fixture has threaded into the site and is not visible.

• After using slow speed motor for fixture installation, Use the cylinder wrench for final tightening by holding the thumb against the top of the wrench and the forefinger around the jawbone.

• 6.Implant placement• Ideally it should be placed such that:• It is within bone along its entire length.• It does not damage adjacent structures• It is located directly apical to the tooth it is replacing and not in an

embrasure space• The angulation of the implant is consistent with the design of the

restoration• The top of the implant is placed sufficiently far under the mucosa to

allow a good emergence profile of the prosthesis. This is often achieved by countersinking the head of the implant.

7.Soft tissue adaptation and suture procedures

Suture the midline initially then continue from the distal borders of the surgical site towards the midline.

The suture should not be placed directly over the cover screw to avoid risks of fistula formation.

 Incision is closed in position buccal to implant placed

Post operative care

• After implant surgeries the patients should be warned to expect:• Some swelling and possibly bruising• Some discomfort which can be controlled with oral analgesics• Some transitory disturbance in sensation if surgery has been

close to nerve.• In most circumstances not to wear denture over the surgical site

for atleast 1 week.• To use analgesics and ice packs to reduce swelling and pain• To keep the area clean by using chlorhexidine mouthwash 0.2%

for 1 min twice daily.• Not to smoke. Ideally patients should stop smoking for some

weeks before the surgery and for as long as possible therafter.(BDJ, VOL187,NO. 8, OCT 23, 1999, 419)

FUTURE BONE AUGMENTATION APPROACHES

• BMPs are differentiation factors that are part of the transforming growth factor superfamily.

• Two of these proteins, BMP-2 and -7 (or osteogenic protein-1), have been cloned, studied extensively, and show promise for intraoral applications

Human studies demonstrated product safety with BMP-2 in ridge preservation and sinus augmentation applications.

• Platelet derived growth factor (PDGF) has received the most attention for intraoral use

• Gene therapy is a relatively new therapeutic modality based on the potential for delivery of altered genetic material to the cell. Localized gene therapy can be used to increase the concentration of desired growth or differentiation factors to enhance the regenerative response

Bone Augmentation Techniques,Bradley S. McAllister and Kamran Haghighat, J Periodontol • March 2007, vol 78;3:386

CONCLUSION

• Improvements of the techniques seem to be a reliable way of increasing oral implant success.

• By using proper techniques and newer graft materials according to the demanding situations, implant dentistry is bright we can make it brighter!

REFERENCES

1. Implants in dentistry , Michael s block, John N kent, Luis R Guerra2. Contemporary implant dentistry,3rd editin, Carl e misch3. Clinical practice of mainstream implant dentistry, bone

enhancement section 34. Bone, ARUN Garg5. Clinical Periodontology and Implant Dentistry, 5th edition, Jan Lindhe6. Membrane barriers for guided tissue regeneration, Arun K Garg,7. Periodontal Therapy: Clinical approaches and evidence of success,

Vol. 1, Myron Nevins and James Mellonig.8. Osseointegration and full mouth rehabilitation, Sumaiya Hobo

 

9. Basic Implant Surgery , Richard Pslmer, paul parmer, peter Floyd, BDJ ,oct 1999; 187:8:415

10. Maxillary sinus grafting, Michael s Block, John n Kent, pg 47811.Atlas of oral implantology, A Norman Cranin 2nd edition.12 .Contemporary implant dentistry, Carl E misch, 3rd edition13. Biology, harvesting, grafting for dental implants, rationale and

clinical applications, Arun K Garg14.Immediate implant placement: treatment planning and surgical

steps for successful outcomes, British Dental Journal; vol 201; no 4; aug 26, 2006:199-205.

15.Bone Augmentation Techniques ,J Periodontol • March 2007, vol 78;3:386 McAllister, Haghighat

16. Bone augmentation by means of barrier membranes,Christoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33, 2003, 36–53

17. Implant dentistry, Palmer 1st edition18. A colour atlas:The branemark system of oral reconstruction,

Richard A

THANK YOU