University of Glasgow
2013
Molar Distalization
Dr. Mohammed Almuzian
Contents Definitions
Indications for Molar Distalization
Indications for Arch lengthening
Limitations & Contraindications
Amount of Distalization
Techniques of distalization
A.Mini-Distalisation techniques
B. Macro-Distalisation techniques
1. Compliance Appliance
Lip bumper
Removable Functional Appliances
Headgear (HG)
Upper Removable Appliance
Nudger appliance and HG combination:
En mass removable appliance
Molar Distalising Bow
Class II Mechanics (CLII elastic with sliding jigs):
2. Non-compliance CLII correctors
The Herbst appliance
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History
Design
Advantages
Disadvantages
Effects of the Herbst Appliance
Indications
Contra-indications
Jasper Jumper
Effects of the Jasper Jumper
Indications
Contra-indications
The Adjustable Bite Corrector™ (twin force)
The Eureka Spring™
Saif Springs
Requirements
The Mandibular Anterior Repositioning Appliance (MARA)
The AdvanSync appliance
History
Design
Fixed twin block
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History
Advantages
Disadvantages
Intra-maxillary Appliance
Pendulum Appliance
Evidences
Retention after pendulum
Jones Jig™ and Lokar Distalizing Appliance
Distal Jet
Nance Arch and Coil Springs
Repelling Magnets
Goshgarian appliance
Implant
Conclusion
Retention after molar distalization
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Molar Distalization & arch lengthening
Definitions
Arch lengthening: Increasing the arch length using distal movement of
posterior teeth (molar distalization) or proclination of incisors. Any change
in arch form is likely to relapse so lengthening must be kept to a minimum
Molar Distalization: Orthodontic mechanics that aim to move the buccal
segment posteriorly in order to provide space for orthodontic purposes. It
is considered a method of arch lengthening.
Indications for Molar Distalization
1. Space provision in order to:
Correct up to 1/2 unit Class II molar relationship
Relieve mild increased in the overjet (Felton et al., 1987).
Provide extra space in severe crowding cases in which extractions fail to
provide sufficient space (Chung, 2008).
Treatment of midline deviation problems (Holmes, 1989).
2. Interceptive applications:
To provide space for spontaneous eruption of ectopic canines. This has been
shown to have a success rate of 80% compared to 50% in control group
(Leonardi, 2004).
To regain a lost space due to mesial migration of molars in premolar
crowding cases (Kennedy, 1987).
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Uprighting of upper first molars when they are impacted against upper
deciduous second molars (Kurol & Bjerklin, 1984, Kennedy & Turley,
1987)
Indications for Arch lengthening
It includes the above indications for Indications for Molar Distalization in
addition to the followings:
1. Correction of incisal relationship in CI III case by proclination of
upper incisors
2. Correction of retroclined mand incisors in class II D2 cases with
mandibular incisors trapped behind upper incisors, this will aim in
providing space for crowded teeth as well as reduction of OJ and OB.
3. Correction of retroclined mand incisors in class II D1 cases with
mandibular incisors trapped in palate, this will aim in providing space for
crowded teeth as well as reduction of OJ and OB.
Limitations & Contraindications
1. Protrusive profiles, increased overjet or proclined incisors since most of
the distalisation techniques result in loss of anchorage in a form of incisor
proclination which might worse the already proclined incisors and the
overjet.
2. Thin labial bone and gingivae: For the same reason mentioned above, it is
recommended to avoid distalisation in cases with thin labial bone and
gingivae due to the high risk of gum recession and dehiscence associated
with the resultant incisor proclination (Aziz 2011, Melsen & Allais, 2005)
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3. High Frankfurt mandibular plane angles & anterior open bites since the
majority of distalisation methods are extrusive in nature and would drive
the molars posteriorly resulting in a possibly wedging effect that open the
occlusion.
4. Significant crowding (more than 6 mm) since the maximum amount of
space regaining by molar distalization is 2 - 2.5mm (Atherton et al, 2002)
5. Posterior crossbite since the distalised molars would sit in the narrow
relationship with the opposing dentition due to distal movement of the
molar toward the wide part of the dental arch. The midpalatal jackscrew is
activated twice a week to create this expansion in the molar region.
6. Buccally flared molars since the force applied buccal to centre of rotation
causing buccal tipping. Other reason might be that the cortical bone of
these teeth is less resistant than lingual bone which favour the buccal
tipping. This might compromise the overbite and cause posterior rotation
of the mandible. However, the distal jet appliance apply its force from
palatal side and close to the centre of rotation, so it is claimed to be better
in this issue.
7. Rotation and tipping: As the molar is tipped distally, it has a tendency to
rotate distopalatally. This is thought to be due to the nature of the cortical
bone surrounding these teeth; this can be compensated for somewhat by
placing approximately 30 degrees of distal rotation in the terminal legs of
the Pendulum springs. (Hilgers, 1992)
8. Shallow palatal vault especially if the intraoral appliances are used which
rely mainly on the palatal bone anchorage in its action.
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Amount of Distalization
1. Atherton et al (2002) in their systematic review came to the conclusion that
the most distal movement of the molars that could be achieved was in the
range of 2 - 2.5mm.
2. Melsen and Dalstra (2003) in their retrospective study found that the total
distal movement of the molars in patients who wore cervical head-gear for
an 8-month period did not differ from that of an untreated group when re-
evaluated 7 years later.
Timing
Karlsson 2008, concluded that the best time to move maxillary first molars distally is before eruption of the second molars because:
More space can be gained There is less anchorage loss Less time consumed Better patient compliance
Techniques of distalization
A. Mini-Distalisation techniques
1. Brass wire ligature, elastomeric separators & steel spring clip separators all
act by disimpacting the tooth if it is mesially impacted against other and
this would aid in distalising the tooth and upright it for better eruption
(McDonald & Avery, 1994).
2. Halterman appliance (transpalatal arch on second deciduous
molars with attached distal spring to upright the molars)
(Roberts, 1986).
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3. Humphrey appliance (Nance appliance with a welded finger spring to the
deciduous molar bands to distalise the permanent
molars) (Roberts, 1986)
B. Macro-Distalisation techniques
1. Compliance Appliance
I. Lip bumper: It mainly consists of a thick round stainless steel wire that fit
in the headgear tube of the molar band and stays away from the labial
surface of the incisor by the effect of the loop mesial to the entrance to the
molar tube. The acrylic pad is embedded in the anterior part of the wire
and act to actively displace the lip forward. The reciprocal force of the
displaced lip will be transferred to the molars via the heavy wire and result
in molar uprighting and distalisation. As a consequence of the change in
the soft tissue equilibrium by the lip pumper, there is a proclination in the
incisors under the effect of tongue as well as increase in the intercanine
width (Cetlin & Ten Hoeve, 1983).
II. Removable Functional Appliances: One of the effects of the functional
appliance is correction of molar relationship. This is mainly achieved by
skeletal changes (19% maxillary base and 22% mandibular base) as well as
dentoalveolar changes (26% maxillary dentition and 33% mandibular
dentition) (O’Brien, 2003).
III. Headgear (HG): It is attached directly to molar bands on the first molar
(mainly upper) in a high or low pull direction depending on the incisor
overbite. The force level is 250-300gm per side and the appliance used 14
hours/day. It could achieve 2-3mm of molar distalisation (Atherton et al.,
2002)
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IV. Upper Removable Appliance (Nudger appliance): consists of 0.6mm
palatal finger springs or screw as an active component. Southend on the
incisors as well as Adam clasps on molars and premolars (except the tooth
to be moved) would aid in retention. Sometime, if there is extensive
space loss, an anterior biteplate may be needed to free up the occlusion
to permit uprighting of the tilted permanent molar. However the
anchorage loss manifests as an increase in the overjet (Lewis & Fox,1996)
V. Nudger appliance and HG combination: An upper removable appliance
(URA) with palatal finger springs (activation of 2-3mm) that acts to tip the
crown of the molar distally. High-pull headgear at night, directed above
the centre of rotation of the molar, acts to distalise the root and hold
the movement achieved during the day time by the URA, (Cetlin & Ten
Hoeve, 1983). In addition, the headgear provides a method of reinforcing
the anchorage during subsequent retraction of the anterior teeth. Ferro et al
(2000) showed an average of 20-25% anchorage loss with a Nudger
appliance used with cervical headgear.
VI. En mass removable appliance: It involves upper removable appliance to
which a headgear (200-300gm per side for 14 hours) is attached through a
facebow. Extraction of the upper second molars may be required and this
claimed to achieve 6mm molar distalisation (Orton, 1996).
VII. Molar Distalising Bow: It consists of two components. First, a 0.8–1.5 mm
thick thermoplastic splint covering all teeth except the teeth to be moved
and it extends into the buccal sulcus for better support and retention. A
distalising bow fits into the anterior slot that is embedded in the splint and
carries an open coil springs to apply a force to the molars. (Rakosi, 1991)
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VIII. Class II Mechanics (CLII elastic with sliding jigs): This was a mainstay
of the original Tweed technique in which the force from Class II elastics
aid in pushing the upper molars distally via a sliding jig. The force level is
250 gm per side is needed. In addition the class II elastic help in correction
of class II malocclusion by clockwise rotation of the occlusal plane which
can be compensated in growing patient. This is why it should not be used
for more than 6 months in adult patient (Tweed, 1967)
2. Non-compliance CLII correctors
Classification of non-compliance CLII correctors (McSherry 2000)
Inter-maxillary
1. Herbst appliance
2. Jasper Jumper™
3. Adjustable bite corrector™
4. Saif Springs
5. Eureka Spring™
6. Mandibular anterior repositioning appliance (MARA)
7. Fixed twin-block
8. AdvanSync Molar-to-molar appliance developed by Terry Dischinger
Intra-maxillary
1. Pendulum/Pend-X appliance
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2. Modified Nance arch with nickel-titanium coils or wire
3. Distal jet
4. Jones Jigs & Lokar distalizing appliance
5. Magnetic appliances
6. Absolute anchorage (Palatal implants, TADs, Onplants)
The Herbst appliance
A. History: It was first described by Dr Herbst and popularized by Pancherz
1979.
B. Design:
Fixed functional.
Bands on upper and lower 6’s and 4’s
Palatal bar and lingual bar
Telescopic arms form upper 6’s to lower 4’s
C. Advantages
According to O'Brien study 2009, Herbst was superior to Twin Block
when we measured:
Speech interference
Disturbance of sleep
Influencing school work
Feelings of embarrassment
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Better success rate than Twin Block
It can be used with fixed appliance. Recently a Flip-Lock Herbst
assembly with the 'male' attachments welded to rectangular tubing, which
is slid over a rectangular archwire. This mechanism is very simple to
install and to date is encouragingly robust.
D. Disadvantages
1. Expensive
2. Breaks more significant and mechanical failure of piston assemblies.
3. Cement problem
4. Removal difficulty.
5. Enamel decalcification.
6. Recommended in the permanent dentition only
7. If joined with FA treatment, it should use when full arch SS in use.
8. Inability to incorporate arch expansion during the functional phase
9. Do not grow mandibles and in contrast to others, there is evidence of
sufficient satisfaction with other simpler functional - in particular the
twin-block.
10.More lower incisor proclination
E. Effects of the Herbst Appliance
1. Restraining effect on maxillary growth
2. A stimulating effect on mandibular growth.
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3. Sagittal molar correction was 43 per cent due to skeletal changes and 57
per cent due to dentoalveolar changes.
4. The overjet correction was 56 per cent due to skeletal changes and 44 per
cent due to dento-alveolar changes. Pancherz (1979)
5. Dento-alveolar changes include lower incisor proclination and maxillary
molar distalization and intrustion. The changes are similar to those
produced by high pull headgear (Pancherz and Anehus-Pancherz, 1993).
6. Vertically, the overbite is reduced. This occurs by intrusion of lower
incisors and enhanced eruption of lower molars (Pancherz, 1995)
7. The long-term effect on mandibular growth is uncertain and may only have
a short-term effect on skeletal growth pattern (Pancherz and Fackel, 1990).
8. Hansen et al. (1990) found that the appliance did not have any adverse
effects on the temporomandibular joint (TMJ).
F. Indications
a. Dental Class II malocclusion.
b. Skeletal Class II mandibular deficiency.
c. Deep bite with retroclined mandibular incisors.
d. Pancherz (1995) also recommends its use in post-adolescent patients,
mouth-breathers, uncooperative patients, and those that do not respond to
removable functional appliances
G. Contra-indications
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a. Cases predisposed to root resorption.
b. Dental and skeletal open bites.
c. Vertical growth with high maxillomandibular plane angle and excess lower
facial height.
Jasper Jumper
• The Jasper Jumper™ consists of two vinyl
coated auxiliary springs attached to the
maxillary first molars posteriorly and to the
mandibular archwire anteriorly with the springs
resting in the buccal sulcus.
• The springs hold the mandible in a protruded position.
• They are attached to the maxillary first molar headgear tube with a soft wire
with a ball on one end.
• The amount of mandibular advancement is adjusted by lengthening or
shortening the maxillary connection wire.
• The jumper mechanism fits over the lower archwire. (Blackwood, 1991).
• A heavy archwire with lingual root torque is used in the mandibular dental
arch in order to maintain lower anchorage.
• There also is a danger of lower incisor proclination if the archwire is not tied
back.
• Usually, 6–9 months of Jumper wear is necessary in order to correct a mild
Class II problem in patients who still have some growth remaining.
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• Additional treatment time may be required in patients with more severe
problems.
Effects of the Jasper Jumper
Cope et al. (1994) quantified the action of the Jasper Jumper showing that
the majority of the action was due to dental, rather than skeletal change,
although the maxilla underwent significant posterior displacement and the
mandible clockwise rotation.
Indications
1. Dental Class II malocclusion.
2. Skeletal Class II with maxillary excess as opposed to mandibular
deficiency.
3. Deep bite with retroclined mandibular incisors.
Contra-indications
1. Cases predisposed to root resorption.
2. Dental and skeletal open bites.
3. Vertical growth with high mandibular plane angle and excess lower facial
height.
4. Minimum buccal vestibular space.
The Adjustable Bite Corrector™ (twin force )
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The Adjustable Bite Corrector similar to
the Herbst appliance and the Jasper
Jumper.
The advantages include universal left
and right sides, adjustable length, stretchable springs, and easy adjustment
of the attachment parts. No long-term studies have been carried out on this
appliance in the present literature to date.
The Eureka Spring™
It is a fixed inter-maxillary force delivery system.
The main component of the spring is an open wound coil
spring encases in a telescoping plunger assembly.
The springs rest in the buccal sulcus and attach posteriorly
to headgear tubes on the upper first molars, and anteriorly
to the lower archwire distal to the cuspids
The appliance is designed to be used in conjunction with
heavy rectangular lower arch in place.
Labial root torque to the lower incisors
Buccal root torque should be applied to the upper first molars.
The appliance should only be used in conjunction with a transpalatal bar.
The effects of this appliance only dental
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Saif Springs
These are long nickel-titanium closed coil springs that are used to
apply Class II inter-maxillary traction when fully banded
fixed appliances are in place .
The springs are available in two lengths 7 and 10 mm.
It can be used as CLIII elastic
Requirements
1. stabilization of each arch with a large rectangular archwire;
2. direction of force as horizontal as possible (from U7 not U6);
3. sufficient resistant torque (lower incisor lingual crown
torque);
4. perfect fit of bands;
5. proper placement of hooks for spring attachments
The Mandibular Anterior Repositioning Appliance (MARA)
It consists of Elbow shape wire attached to
tubes on upper first molar bands or stainless
steel crowns.
A lower first molar crown has arm projection
which engages the Elbow of the upper molar. The appliance is adjusted so
that when the patient closes, the Elbow wire guides the lower first molars
and repositions the mandible forwards into a Class I relationship.
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It is recommended a 12-month treatment time to achieve a bite jumping or
orthopaedic effect.
Stabilization of the lower molars is assisted by the fitting of a lingual arch
and on the upper arch a transpalatal bar to stabilize the upper molars is
placed.
This appliance does not require the placement of attachments on teeth other
than the first molars.
The treatment results of the MARA were very similar to those produced by
the Herbst appliance but with less headgear effect on the maxilla and less
mandibular incisor proclination than observed in the Herbst treatment
group. Pangrazio-Kulbersh 2003
The AdvanSync appliance
A. History: Developed by Terry Dischinger in 2008
B. Design:
This molar-to-molar fixed functional assembly
The name of the appliance therefore reflects that the mandible can be
postured forward synchronously with the start of all the other fixed
appliance tooth movements.
The appliance requires no laboratory work
Molar band separation at one visit permits selection and cementation of the
molar attachments at the next visit.
These attachments are similar to a hybrid between a molar band and a
preformed crown.
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The telescoping arms have a long range of action and permit good lateral
excursion and are very easily advanced either by means of the alternative
screw position on the lower molars or via C rings which are crimped over
the pistons.
Fixed twin block
A. History: Developed by Mike Read (2001).
B. Advantages
Robustness and possibly patient comfort
Because the two halves of the appliance are not permanently linked
together, the problems of leverage on the fixation points does not arise
during mandibular excursion in contrast to Herbest appliance.
Integration of FA is easy from the start
No lateral open bite.
C. Disadvantages
• OH problems and decalcification
• Need for lower premolar bands to remain securely cemented.
• Not quick and easy for all clinicians to make, fit and adjust as well as
robustness.
• Need technical development and extra experience are continually bringing
improvements.
Intra-maxillary
Pendulum Appliance
This appliance first described by Hilgers (1992)
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It uses a large Nance button in the palate for anchorage and 0•032-inch
(0.8mm) TMA springs that deliver a distalizing force to the upper molars.
The springs insert into lingual sheaths on the palatal surface of the band.
The anterior portion of the appliance is retained with premolar bands, which
are joined to the appliance using a retaining wire (or can be bonded to the
tooth directly).
Occlusally-bonded rests on the primary molars or second premolars add to
the retention.
If expansion of the upper arch is indicated, then a midline screw can be
added to the appliance. This version of the appliance is known as the Pend-
X appliance.
Evidences
Byloff and Darendeliler (1997) showed that
The appliance moved molars distally without creating bite opening, but the
molars did tend to tip.
3mm of distalization associated with 1mm of anchorage loss.
If molar uprighting bends were incorporated into the appliance it reduced the
tipping, but increased the anchorage loss to 1.5mm for each 3mm of
distalization. (Byloff et al., 1997).
Ghosh and Nanda (1996) showed that
for every millimetre of distal molar movement, the premolar moved
mesially 0•75 mm.
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Hilgers (1992) reports that when
The appliance is placed before the eruption of the second molars, two-thirds
of the tooth movement is molar distalization, one-third is experienced as
forward shift of the anchor bicuspids.
If placed after eruption of the second molars, the experience tends to be
reversed, one-third distal movement of the first molar, and two-thirds
anchorage slip.
Pendulum appliance provides a better patient perception and shorter duration
of treatment in comparison to HG in relation to (Ye et al 2005)
Jambi et al in their Cochrane review in 2013 suggested that intraoral
appliances are more effective than headgear in distalising upper first
molars. However, this effect is counteracted by loss of anterior anchorage,
which was not found to occur with headgear when compared with intraoral
distalising appliance in a small number of studies. The number of trials
assessing the effects of orthodontic treatment for distilisation is low, and
the current evidence is of low or very low quality
Retention after pendulum
However the molars were moved distally, they must be held there while the
other teeth are then retracted to correct the overjet.
Simply leaving the distalization appliance in place for 2 to 3 months leads to
distal movement of the premolars by stretched gingival fibers,
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As soon as the original premolar-based lingual arch and palatal pad are
removed, a new lingual arch and pad from the distalized molars must be
placed.
Even so, especially if the molar tipped distally, it will tip mesially again as
the space closes.
Placing a tipback in the distalizing springs will keep the molar more upright
and minimize relapse, but this increases the extrusive tendency, so as with
headgear, the most successful molar distalization with the pendulum
appliance occurs in patients who have vertical growth during their
treatment.
Even so, data show that on the average, much of the original distalization is
lost during the second phase of treatment with a complete fixed appliance
Jones Jig™ and Lokar Distalizing Appliance
These appliances use open coil nickel-titanium
springs in to the upper first molars, and use a
Nance button attached to the upper first or
second bicuspids or the primary molars (Jones
and White, 1992).
A similar mechanism, called the Lokar distalizing appliance, has been
developed by Ormco Corporation. It has reported advantages of ease of
insertion and ligation.
Paul & O’Brien (2001) found no difference between Nudger URA+HG
and Jones jig for molar distalisation.
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Distal Jet
Developed by Carano et al. (1996)
They claim that it overcomes the disadvantages of other appliances for
distalizing molars by reducing the tendency for the teeth to tip. The force
acts through the centre of resistance of the molar and
thus is said to translate the tooth
Bilateral tubes of 0•036-inch internal diameter are
attached to an acrylic Nance button. A coil and screw clamp are slid over
the tube.
The wire from the acrylic ends in a bayonet bend and inserts into a palatal
sheath on the molar band.
The Nance button is also attached to a premolar band via a connecting wire.
Bondemark (2004) in a randomised controlled trial compared HG and the
distal jet and found that the distal jet was more effective than the HG in
creating distal movement of maxillary first molars but anchorage loss was
greater with the distal jet.
Nance Arch and Coil Springs
Several authors have described the use of a modified Nance arch with coils
to distalize molars.
One of these studies compared the effect of modified Nance arch with coils
MNA and the repelling rear earth magnet RRRM in distalising the molars.
It showed that the amount of molar distalization was more in the MNA
Mohammed Almuzian, University of Glasgow, 2013 23
group than RRRM group with a better patient perception with the former
group. (Bondemark et al, 1994)
Repelling Magnets
it had been showed that it is possible to achieve molar distalisation using
repelling magnets with a faster result when second molars are unerupted
(Bondmark, 1992).
However one of the difficulties of using the magnet is the force decay over
time with subsequent needs for frequent activation (weekly basis) in
addition to difficulty of using it with other metallic appliances like
headgear (Gianelly et al. 1989).
Anchorage loss in a form of increased OJ is a normal findings
Goshgarian appliance
Goshgarian appliance can be used in distalization the molars unilaterally or
bilaterally to correct mild class II by complicated ways of activating the V
shape bend of the TPA as described by Rebellto in 1995.
In unilateral case it is better to reinforce the stable side with headgear, place
torque in the archwire to take advantage of cortical anchorage or use
temporary anchorage devices (Haas, 2000, Burston 1980, Rebellto, 1995,
Cooke and Wreakes, 1978; Ten Hoeve, 1985; Dahlquist et al., 1996;
Ingervall et al., 1996, Rebellto 1995, Ten Hoeve, 1985; Man-durino and
Balducci, 2001)
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Implant
Mini Implants: Ismail & Johal (2002) used mini implants for anchorage to
distalise molars.
They showed that suitable sites for the implant
are palatal vault and retromolar region.
If extractions of the second molars are carried
out then 4-5mm of distalisation is achievable.
Other uses of the miniscrew implant in the distalisation of the molars is by
supporting distal jet appliance (Karaman et al 2002) or bone anchored
pendulum anchorage (Kircelli et al, 2006)
Retention after molar distalization
Hilgers 1998
1. Overcorrection
2. Quick-Nance
3. Short term headgear
4. Stops on archwires
5. Upper utility arch
6. Class II elastics
7. Lip bumper
8. Hawley or clear-type retainers
9. Bionator
10. Herbst appliance
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In details
Overcorrection
Simply put, just moving the upper molar back into a Class I occlusion is
most often not enough. Moving it back into a Class III relationship is more
desirable.
Quick-Nance
It preformed Nance cribs fabricated from .032 stainless steel, The .032
wire size is utilized because it is easily placed recurved to fit into the .036
lin-gual sheath.
The Nance button cannot be placed over already inflamed or compressed
tissue. When the palatal tissue is inflamed, the use of a clear immediate
(Tru-Tain type) retainer for approximately one week will allow for
adequate recovery of the tissue.
Short-term Headgear
It also helps distally upright molar roots.
The outer bow is kept high, above the center of resistance of the tooth, and
moderate-force loads applied (250-350 grams/side).
Stops on Archwires
This will prevent the upper molars from sliding forward
By placing a stop at the molar, any rebound will be expressed as flaring or
forward movement of the upper arch. Therefore, other anchorage
techniques must always be used in conjunction with stops on the archwire.
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Upper Utility Arch
Indications
1. Can be used without full eruption of the buccal segment teeth,
2. There is no loss of anchorage caused by archwire friction when retracting
the buccal segments.
3. In class II D2 with sever deep bit because any rebound would be beneficial
to proclined the severely retroclined upper incisor and thus reducing the
overbite.
4. If Cl II elastics are going to be one of the anchorage sources , the utility
arch acts as the forward purchase point for the elastics.
Class II Elastics
Early use of Class II elastics means early bonding of the lower arch, which
can be difficult with the locked-in overbite. A utility arch or reverse curve
Ni-Ti is often used at the very outset of Pendulum therapy to clear the
lower arch for bonding.
Upper Lip Bumper
An .040 lip bumper with a soft covering in the labial vestibule is adapted
above the upper incisor brackets.
Clear (slipcover) or Hawley-type retainers
Utilized when tissues are too inflamed for immediate transition to fixed
appliance.
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Bionator
The Bionator or removable functional appliance is used for Pendulum
anchorage in those brachyfacial types with short mandibular corpus length.
It serves to maintain the distalized molar position while developing the
lower arch forward.
Herbst appliance
This version of the classical Herbst appliance is easy to use, allows for
adjunctive bonding and space closure of the upper arch .
Summary of the evidences
1. Indications for Molar Distalization as Interceptive applications
(Leonardi, 2004) To provide space for spontaneous eruption of
ectopic canines. This has been shown to have a success rate of 80%
compared to 50% in control group
Kennedy, 1987).To regain a lost space due to mesial migration of
molars in premolar crowding cases
Kurol & Bjerklin, 1984)Uprighting of upper first molars when they
are impacted against upper deciduous second molars
2. Limitations & Contraindications of distalization,
Atherton et al, 2002) Significant crowding more than 6 mm) since
the maximum amount of space regaining by molar distalization is 2 -
2.5mm
Atherton et al 2002) Amount of Distalization, in their systematic
review came to the conclusion that the most distal movement of the
molars that could be achieved was in the range of 2 - 2.5mm.
Mohammed Almuzian, University of Glasgow, 2013 28
Melsen and Dalstra 2003) in their retrospective study found that the
total distal movement of the molars in patients who wore cervical
head-gear for an 8-month period did not differ from that of an
untreated group when re-evaluated 7 years later.
3. Karlsson 2008, Timing of Distalization, concluded that the best time
to move maxillary first molars distally is before eruption of the second
molars
4. Cetlin & Ten Hoeve, 1983).lip bumper
5. O’Brien, 2003) Removable Functional Appliances: One of the effects
of the functional appliance is correction of molar relationship. This is
mainly achieved by skeletal changes 19% maxillary base and 22%
mandibular base) as well as dentoalveolar changes 26% maxillary
dentition and 33% mandibular dentition
6. Cetlin & Ten Hoeve, 1983).Nudger appliance and HG combination
7. Orton, 1996).En mass removable appliance Extraction of the upper
second molars may be required and this claimed to achieve 6mm
molar distalisation
8. Rakosi, 1991) Molar Distalising Bow
9. Tweed, 1967) Class II Mechanics CLII elastic with sliding jigs):
10.O'Brien study 2009, Pancherz, 1995) The Herbst appliance
11.Cope et al. 1994), Effects of the Jasper Jumper
12.Mike Read 2001). Fixed twin block
13.Hilgers 1992): The appliance is placed before the eruption of the
second molars, two-thirds of the tooth movement is molar
distalization, one-third is experienced as forward shift of the anchor
bicuspids. If placed after eruption of the second molars, the
Mohammed Almuzian, University of Glasgow, 2013 29
experience tends to be reversed, one-third distal movement of the first
molar, and two-thirds anchorage slip.
14. Ye et al 2005) Pendulum appliance provides a better patient
perception and shorter duration of treatment in comparison to HG
15.Paul & O’Brien 2001) found no difference between Nudger URA and
Jones jig for molar distalisation.
16.Bondemark 2004) found that the distal jet was more effective than the
HG in creating distal movement of maxillary first molars but
anchorage loss was greater with the distal jet.
17. Bondemark et al, 1994) showed that the amount of molar distalization
was more in the MNA group than RRRM group with a better patient
perception with the former group.
18.Mini Implants: Ismail & Johal 2002) used mini implants for
anchorage to distalise molar
19.One of the important systematic review worth mentioned is that done
by Karlsson 2008. He did a systematic review of two RCT studies and
found that the intraoral appliances for molar distalization are more
effective than the extraoral one. However, he recorded a moderate and
acceptable anchorage loss was produced with the former implying
increased overjet whereas the latter created decreased overjet. Bother
appliance did not have any considerable corrective skeletal effect.
Finally he concluded that the best time to move maxillary first molars
distally is before eruption of the second molars.
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