Current trends in molar distalization

Molar distalization
– current trends
INDIAN DENTAL ACADEMY
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• Current orthodontic philosophies have been
oriented toward conservative treatment
modalities to avoid extractions and, at the same
time, to try to eliminate the need for patient
cooperation; consequently, there are many
devices for gaining space, particularly for the
distalization of the maxillary molars.


• The appliances used for molar distalization can
be divided into
• Removable appliances and
• Fixed appliances.
Removable appliances are:
• Extra oral traction
• Removable appliances with finger springs
• Sliding jigs with intermaxillary elastics.

The fixed appliances are
A. Intramaxillary appliance
1. Wislons 3D appliance
2. Repelling Magnets
3.The pendulum appliance
4. Niti based appliances : archwires – single loop,
double loop; Compressed coil springs
5. Jones jig
6. Distal Jet
7. Fixed piston appliances
8. IBMD
9. K-loop 10. Distalix
11.Franzulum appliance 12. Lokar appliance
13. First class appliance 14. Carriere’s Distalizer

B. Intermaxillary appliance:
1. Herbst appliance
2. Jasper Jumper
3. Eureka Spring
4. Klapper superspring
C. SAS supported distalization:


DISTALIZATION DIAGNOSIS
• The first step is to confirm the diagnosis of a
forward maxillary molar position.
• 1. Check the centric relation position (and
vertical status). Before considering the molar
relationship in terms of dental or skeletal
malocclusion, it is desirable to check the TMJ
status. All records must be correlated, ie,
cephalo-metrics, functional axiographics, and
radiologic exams (MRI, CT scan).

• Korn has cautioned against using
extraoral force in patients with
undiagnosed meniscus disorders
who are borderline clickers with an
"end-on click.
• a. Korn has shown that the
distalization may push back the
maxillary molar ---• b. causing more posterior tooth
contacts and then moving the
condyle backward into a more
posterior position, now with a "true
click”.
• c. The mandible then assumes its
normal position, but the meniscus is
now too far forward.

• 2. Check the sagittal relationship.
(1) The pterygoid vertical plane (PTV)/maxillary molar
relationship and
(2) the convexity prognosis.
• According to Ricketts, the normal maxillary molar (M1)
position is given by the distal face of the molar to the PTV.
The clinical norm is age + 3 mm, and clinical deviation is 3
mm.
• In good skeletal and dental Class I relationships, the facial
axis normally crosses the mesial cusp of M1.
• However, the maxillary molar analysis must not be static
only, but also dynamic. If the distance M1/PTV is shorter
than the normal measurement, the possibility for distalization
is low and possible extractions will depend on growth
potential and the presence of 3rd molar.
• Therefore, posterior dental arch analysis must include
mesiodistal measurement of all molars to determine the
posterior space available at maturity

1.Brachyfacial
2.Mesofacial
3.Dolichofacial
• To determine a positive convexity, differentiation must be
made between a forward maxilla and a backward mandible.
• Patient age must be considered, to determine what the
positive convexity will be with time and growth.
• For example, a +4 mm convexity at 8 years of age could be
completely different at maturity, according to the facial
pattern.
• In some borderline clinical situations, the long-range growth
forecast could be useful. This might permit the clinician to
know if extraoral force and/or distalization are indicated.

DISTALIZATION INDICATION
• In the growing patient, only the growth prognosis
scientifically reveals the indication for
distalization. When a young patient has a Class II
maxillary molar relationship with a forward
maxilla, the molar relationship could worsen,
remain the same, or improve, depending on
mandibular growth.
• The best way to determine the indication for
distalization is to conduct a Ricketts long-range
growth forecast, from the original profile tracing.
The new convexity and molar relationship can
then be observed.

• Define the treatment objectives to
construct a long-term VTO,
according to the following
procedure:
• 1. Draw the mandibular arch with the
estimated position of the mandibular
incisor and the mandibular molar
position according to the dental arch
analysis.
• 2. Place the maxillary molar in a
corrected Class I on the VTO,
because this is the eventual
therapeutic goal.
• 3. Do the S3 Ricketts
superimposition; superimpose the
VTO tracing on the original tracing,
on the palatal plane with registered
anterior nasal spine

• 4. Determine the necessary
therapeutic molar movement needed
to obtain the correction :
• (1) If the maxillary molar moves
downward, but does not go forward,
distalization would not be
recommended
• (2) If the maxillary molar naturally
moves x millimeters forward,
distalization would not be useful
• (3) If the maxillary molar needs a
back-ward movement of x mm to
finish in a Class I relationship at the
end of growth, then distalization
would be stronglywww.indiandentalacademy.com
indicated.

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INDICATIONS & CONTRAINDICATIONS
THE INDICATIONS FOR MOLAR
DISTALIZATION
1. In non-extraction treatment of Class II
malocclusion cases.
2. In low & average mandibular plane angle cases.
3. In class I skeletal pattern cases.
4. In patients with mild arch length discrepancy.
5. In cases where the upper permanent molars have
moved mesially due to early loss of deciduous molars.
6. In patients where the second molars extractions are
planned or where it has not yet erupted.
7. In second molar extraction cases where the third
molars are well formed and erupting properly.

CONTRAINDICATIONS FOR MOLAR
DISTALIZATION
• In high mandibular plane angle cases.
• Skeletal and Dental open bite
• Class II & III skeletal pattern
• Severe arch length discrepancy patients.


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INFLUENCE OF 2ND MOLAR ON DISTALIZATION OF 1ST
MOLAR
A controversy exists concerning the influence of second
molars on the distal movement of the first molars.
Graber noted that extraoral traction on the first molars, when
the second molars have not totally erupted, led to distal tipping
only and not to bodily distal movement. Bondemark et al (AO
94 Magnets vs NiTi coils) stated that the presence of second
molars did influence tipping and distal movement of the first
molars.
Gianelly (AJO 91 NiTi coils) also found that treatment time
was increased with the presence of second molars.
Muse et al (AJO 93 Wilsons BDA) found that the presence of
maxillary second molars did not correlate with the rate of
maxillary first molar movement or with the amount of tipping
that occurred.

Studies on Pendulum Appliance
• The findings of the Byloff’s study (AO 1997) were
similar to those of Muse et al i.e. no statistically
significant differences in linear or angular changes
were found among three groups of eruption stages of
second molars.
• According to studies by Bussick and McNamara
(AJO 2000March); Ghosh and Nanda (AJO 96); and
Joseph and Butchart (Seminars in Orthod 2000) the
position of the 2nd molar when distalizing the first
molar with a pendulum appliance is of little if any
importance

PG1

PG2

PG3

Kinzinger et al (AJO 2004 Jan) used modified pendulum appliance for
bilateral maxillary molar distalization in 36 adolescent patients in various
stages of the molar dentition.
• In PG 1, eruption of the second molars had either not yet taken place or
was not complete.
• In PG 2, the second molars had already developed as far as the occlusal
plane, with the third molars at the budding stage.
• In PG 3, germectomy of the wisdom teeth had been carried out and the
first and second molars on both sides had completely erupted.
• Analysis of cephalograms to identify any changes in the sagittal plane
showed that, in the direction of distalization, a tooth bud acts on the
mesial neighboring tooth like a fulcrum.

• The degree of distal tipping of first molars was less in
patients with erupted second molars (PG 2 and PG 3) than
in those whose second molars were not yet erupted (PG 1).
• Tipping of erupted second molars was much more marked
in PG 2 but much less pronounced in PG 3 than the
corresponding movement of the second budding-stage
molars in PG 1.
• In PG3 almost exclusively bodily distalization of both
molars is possible, even without bands being applied to the
second molars.
• However, if the first and second molars are distalized
simultaneously with a pendulum appliance, the duration of
therapy will be longer, greater forces will have to be
applied, and more anchorage will be lost.

REMOVABLE APPLIANCES ARE :
• EXTRA ORAL FORCES
• REMOVABLE APPLIANCES
• THE CETLIN APPLIANCE
• EXTRA ORAL FORCES
• One of the earliest methods of molar distalization
introduced and proved to be effective was by extra
oral forces employing use of the head gear.
Components of Head Gear:
• Force delivering Unit:
• Force Generating Unit.
• The Anchor Unit:

SELECTION OF HEADGEAR:
• 1. Headgear anchorage location: location of the anchorage unit
determines the type of force that will be applied to the unit. The
relation of the force to the Cres of the unit to which it is applied
determines the effects that will be produced by the orthopedic force.
– High pull headgear: this applies a superior (intrusive) and distal
force to the maxilla and the maxillary dentition.
– Cervical pull: this produces an inferior (extrusive) and distalising
force on the maxilla.

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Combination headgear: no moment is produced and a
distalising force is applied to the maxilla.

• Since the Cres of the molar is located in the mid root region, force
vectors above this point will result in a distal root movement. Forces
below this point will result in a distal crown movement. Similar
considerations apply to the maxilla.

TYPES OF HEADGEARS:
CERVICAL HEADGEAR:
• This was first introduced by
SILAS KLOEHN in 1947. It is
the most commonly used
facebow in clinical practice.
Typically it is used in growing
patients with decreased vertical
dimension. The purpose of the
facebow is to restrict the forward
growth of the maxilla. The
vector of force is below the
occlusal plane producing both
extrusive and distalising effects.

• Effects of cervical headgear:
– to erupt the entire upper jaw
– tends to move the upper jaw distally
– Steepen the occlusal plane.
– Expansion of the upper arch.
Effect of different positions of the outer bow:
when the outer bow is bent upwards:
The forces that are produced are
A distalising force to the upper teeth, which is good for correction
of class II relation.
When the outer bow is bent upwards, bringing it down to the
occlusal plane tends to produce a negative moment that flattens the
occlusal plane. Hence the steepening effect of the cervical headgear
is nullified.
Eruption of the entire upper arch tends to increase the mandibular
plane angle and tends to worsen the class II skeletal relationship.
this type is good for patients with forward growth rotation

when the outer bow is bent
downwards:
Forces that are produced are

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Positive moment on the occlusal plane
is seen that tends to steepen the
occlusal plane since the pull is below
the Cres.
Extrusive force and a distalising force.

When the outer bow and inner
bow are in the same level, no
moment is produced and there is a
net distalising and extrusive force.
When the outer bow is shorter than the inner bow, the headgear strap
hook is placed too far anteriorly. This results in a greater tendency to
steepen the occlusal plane when the straps are engaged. The pull of the
bow is further forward from the Cres and this tends to steepen the
occlusal plane. When the outer bow is long, there is a tendency to
flatten the occlusal plane.

Advantages
• Direction of pull is advantageous in treatment of short
face class II maxillary protrusive cases with low MPA
and deep bites.
Disadvantages:
• It normally causes extrusion of the upper molars. This
movement is seldom desirable except in patients with
reduced lower anterior facial height. It is
contraindicated in patients with steep mandibular
planes and in open bite cases.


Long term study on cervical headgear:
Melsen et al in AJO 2003 studied the intramaxillary
molar displacement 7 years after treatment with
Kloehn headgear and cervical traction. Two groups of
10 patients were studied. In one group, the outer bow
was tilted upward by 200 and in another group, it was
tilted down by 200. In the group that had the outer bow
tilted downwards, molar correction was faster. In both
the groups, the maxilla was moved backward and
downward. A strong tendency of the molars to return
to the key ridge was demonstrated, and there was no
evidence that the Class I relationship obtained by
extraoral traction was more stable than that obtained
by functional or intramaxillary appliances.

OCCIPITAL HEADGEAR:
• The occipital headgear consists of a
facebow which fits over the occiput of the
head. The force generated by a high pull
(occipital) has both distalising and
intrusive forces since the force is exerted
above the occlusal plane. Such forces are
used in conditions where vertical control
of the molars is important. As growth
guiding appliance, a high pull headgear
can decrease the vertical development of
the maxilla, thereby allowing for
autorotation of the mandible and
maximizing the horizontal expression of
mandibular growth.
Occipital pull with short outer bow (force anterior to Cres)
This results in a force system at the unit’s Cres with a moment that
tends to flatten the occlusal plane and creates distalising and intrusive
components.

b.

occipital pull with force
passing through Cres
• There is no moment that is
created and hence there is no
change in the cant of the
occlusal plane. Intrusive and
distal components of force are
produced.
c. occipital pull with long outer
bow( force posterior to Cres)
• The force system at the unit’s
Cres has a moment that tends to
steepen the occlusal plane.
Intrusive and distalising forces
are produced. This system might
be required in class II open bite
patients.

Advantages:
• These headgears can be used in patients with
steep mandibular planes and in cases wherein
mandibular growth is more vertical than
horizontal. They can also be used in certain
open bite cases caused due to excessive
eruption of buccal teeth.


COMBINATION HEADGEAR.
Combination headgears have both occipital
and cervical traction springs. This is
perhaps the most versatile type because the
pull can be readily controlled by selecting
the force level of the springs and by
controlling the length of the outer bow. For
distal translation of the upper posteriors, a
distal traction is needed that passes through
the Cres, neither above nor below. The
combination type headgear will allow a
distal force straight through Cres by having
equal occipital and cervical components on
the outer bow, which is angled upwards to
allow the force to pass through the Cres.

Based on occlusal plane requirements:
Action desired
Outer bow
angulation
• distal force and flattening - outer bow above
Cres
• distal force and steepening
- outer bow
below
Cres
• distal force and no moment-- outer bow at
Cres


REMOVABLE APPLIANCES

• Alain (JCO 1972) explained the use of a removable appliance for
distalizing the molars. The appliance was originally devised by
G.Vienne and later produced by A.Lorette.
• The appliances were introduced as the appliances with wires
sliding in tubes.
THE PRINCIPLE
• The appliance consists of a stationary part and a movable part.
Both these parts are held together by a long, horseshoe shaped
wire which moves the movable part by virtue of the elasticity of
the wire. Each end of the wire is inserted into a tube, one in the
fixed part of the appliance and the other inthe removable part.

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THE APPLIANCE
The movable part has an adams clasp and two parallel
tubes embedded for the molars to be moved distally.
The stationary part contains the other clasps for the
retention of the plate and one tube which contains the
other end of the horse shoe shaped active wire.
ACTIVATION
Using the 139 plier, the wire coming out of the tube
embedded in the stationary part is bent, which makes
the movable part slide distally.
DISADVANTAGE
A delicate appliance, since the two wires holding the
movable part should do so without binding.

3. THE CETLIN APPLIANCE

JCO 1983 Cetlin and Tenhoe
• The appliance involves a combination of extra oral force in the
form of head gear and an intraoral force in the form of a removable
appliance.
• The Cetlin appliance utilises a removable appliance intraorally to
tip the crowns distally and then an extraoral force to upright the
roots. So the intra oral removable appliance can be called the crown
mover while the extra oral force, the root mover.
ANCHORAGE
• The anchorage for the removable appliance is by proper adaptation
to the palate, an acrylic shield around the four maxillary incisors
and a modified adams clasp on the first premolars.

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THE EXTRA ORAL FORCE
The extra Oral appliance is a headgear which is inserted into
molar tube. The headgear used is generally cervical or a high
pull, depending on the usual consideration of the skeletal
pattern.
THE APPLIANCE
The removable appliance is worn 24 hours a day. The
appliance also contains a bite plane to disengage the molars (to
aid in rapid molar movement).
THE FORCE APPLIED
In the removable appliance, the spring is activated only 1 to
1.5 mm, measured along the occlusal of the molar and it
supplies force on the molars of only 30 gms. The springs are
placed as far gingivally as possible to minimize crown tipping
and to cause molar movement without irritation.
The extra oral head gear on the other hand exerts a 150 gm
force per tooth and is used to control root position. The
headgear is adviced www.indiandentalacademy.com hours/day.
to be worn for 12-14

INTRAMAXILLRY APPLIANCES
WILSONS' RAPID MOLAR DISTALIZATION
Advocated by William L. Wilson & Robert C.Wilson (1984 JCO)
under modular orthodontics.
• the pre-treatment antero-posterior positions. The Wilson
treatment achieves molar distalization without extra oral forces.
• THE CONCEPT
• Newton’s' 3rd law of motion states that 'for every force, there is
an equal and opposite force', (i.e.) for every moment, there is a
counter moment.
• Implicit in Newton’s' law is the concept that control of counter
moments increases the efficiency of the moment of force.
Modular orthodontic units have been designed to control
countermoments, eliminate 'round trips', and reduce headgear
use.

• DESIGN OF APPLIANCE
• Wilson advocates maxillary bimetric
distalizing arches (BDA) and a
mandibular three dimensional lingual
arch. The bimetric arch produces a
coil spring action against the molars
and producing an anterior counter
moment against the incisors, which is
controlled by the wearing of class II
elastics.
• These, in turn, react with a lower
molar mesial force vector which is
controlled by the 3D lingual arch
with a design for anchorage
resistance. This is supplemented by
molar buccal root torque and cortical
resistance to satisfy increased
anchorage needs.

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The vertical component of elastic force is controlled by using
the elastic load reduction principle, in which the elastic force
is reduced to physiologically acceptable levels. Mandibular
anchorage and elastic load reduction control the reactive
countermoments and produce a relatively friction free, rapid
distalizing of molars; without headgear and with preservation
of mandibular arch integrity.
Wilson's Schedule for Maximum Mandibular Anchorage
6 ounce elastics for 5 days.
4 ounce elastics for 5 days and
2 ounce elastics for 11 days.
For minimal mandibular anchorage:
6 ounce for 10 days
3 ounce for 11 days.

REPELLING MAGNETS

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Anthony A. Gianelly (AJO 1989)
Design:
Nance appliance extends anteriorly to the incisor segment by means of an
0.045-inch wire soldered to the lingual aspect of the premolars. The acrylic
component is placed against both the palatal vault and the incisors.
Bilateral distal extensions (0.045-inch wire) with loops at the end are
soldered to the labial aspect of the premolar bands so that the loops
approximate the molar tubes.
Anchoring the modified Nance appliance to the first premolar encourages the
distal drift of the secondwww.indiandentalacademy.com occurs as first molars are
premolars that normally
moved posteriorly.

The modified Nance appliance serves two functions:
• Activation of the magnets
• Contains the reaction force arising from the action of the
magnets.
• Molars were moved distally 2.0 mm while the premolars
moved anteriorly 2.1 mm.
• When 2nd molars were not present, the fastest molar movement
was observed and Class I molar relationships were attained
within 2 to 5 months.
Disadvantages :
• Magnets tend to be expensive and bulky.
• Magnetic force dissipates rapidly with increasing intermagnet
distance.
• Requires frequent recall reactivation appointment.
• Because of these drawbacks, Darendeliler has concluded that
magnets offer no advantage over conventional systems in
molar distalization.

PENDULUM APPLIANCE
JAMES J. HILGERS, JCO 1992
• The Pendulum Appliance is a hybrid
that uses a large Nance acrylic button
in the palate for anchorage, along with
.032" TMA springs that deliver a
light, continuous force to the upper
first molars without affecting the
palatal button. Thus, the appliance
produces a broad, swinging arc— or
pendulum— of force from the midline
of the palate to the upper molars.


Fabrication
• The right and left Pendulum
springs, formed from .032" TMA
wire, consist of a recurved molar
insertion wire, a small horizontal
adjustment loop, a closed helix, and
a loop for retention in the acrylic
button.
• The springs are extended as close to
the center of the palatal button as
possible to maximize their range of
motion, to allow for easier insertion
into the lingual sheaths, and to
reduce forces to an acceptable
range.

• The anterior portion of the appliance can be retained in place
with occlusally bonded rests or soldered to bands on either the
deciduous molars or the first and second bicuspids.
• The Nance button should be made as large as possible to
prevent any tissue impingement. It should extend to about 5mm
from the teeth, to avoid the highly vascular cuff of tissue near
the teeth and to allow adequate hygiene.
• If expansion of the upper arch is needed, a midpalatal jackscrew
can be incorporated into the center of the Nance button . The
screw is activated one-quarter turn every three days, after a
week or so for patient adjustment, to produce a slow, stable
expansion. This version of the appliance is called a "Pend-X".

Preactivation and Placement
• The springs should be bent parallel to the midline of the palate.
About one-third of this overactivation is lost in placement, and
the remaining pressure is tolerated easily by the patient.
• Once the appliance is cemented in place, each Pendulum spring
is brought forward with finger pressure, the mesial end of the
recurved loop is grasped with a Weingart plier and the spring is
seated in the lingual sheath. . Distal pressure holds the spring in
the sheath quite effectively, but an elastic "O" ring can be used
to secure it.

• A. As the molar is driven distally, it moves on an arc toward the
midline of the appliance— in other words, toward crossbite.
• B. This tendency can be counteracted by opening the adjustment
loop slightly to increase the expansion and molar rotation.
• Distal root tip can also be produced by adjusting this horizontal
loop on the Pendulum spring. Tipping back the recurved portion
of the spring at the loop causes a more direct distal movement of
the molars.

Reactivation
• The spring is reactivated by
pushing the centre of helix
distally toward the midline
with a bird beak plier.
Stabilization
• Molars must be stabilized in
their new distalized
positions or they will
rapidly drift back mesially.
It is also important to move
the buccal segments into a
Class I relationship to
harness the full advantages
of the appliance. www.indiandentalacademy.com

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The molars can be stabilized in any of four ways:
The Nance portion is removed and a full upper fixed
appliance is bonded. An upper utility arch holds the
molars back with the incisors as anchorage.
After removal of the Pendulum Appliance, a smaller,
easier-to-clean Nance button ("Insta-Nance”) is placed.
The entire upper arch is bonded and a continuous
archwire with omega loops mesial to the upper first molar
tubes is placed.
A headgear is worn.
Drawbacks of PA
The pendulum appliance not only drives the molars
distally, there is also a slight lingual tipping.
Causes the anterior bite to open
Not very easy to fabricate.

MODIFICATIONS IN PA
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SCUZZO JCO 1999 Nov
The Modified Pendulum:
M-Pendulum
In the original design by Hillgers,
adjustable loop was distally oriented
to compensate for the tendency
toward crossbite during distalization.
M-Pendulum was designed by
reversing the loop to the mesial to
provide bodily movement of both the
roots and crowns of the maxillary
molars, rather than tipping or
rotation. After some distalization
has occurred, the loop is reactivated
simply by opening it.

Hillgers design

M Pendulum

• If the horizontal Pendulum loop is inverted, it will
allow bodily movement of both the roots and crowns
of the maxillary molars. Once distal molar movement
has occurred, the loop can be activated simply by
opening it. The activation produces buccal and/or
distal uprighting of the molar roots and thus a true
bodily movement rather than a simple tipping or
rotation.

• Before intraoral placement of the appliance,the Pendulum
springs are activated to about 40-45° with a Weingart plier,
resulting in about 125g of force on each side. This activation is
repeated until the desired distalization of the molars is
obtained.
• The inverted loop should not be adjusted until the spring has
deactivated following each phase of distalization. A passive fit
of the distal ends of the Pendulum springs in the lingual
sheaths, with no distal force applied to the molar crowns, will
allow backward tipping of the molar roots. The terminal ends
of the M-Pendulum springs are straight, rather than looped as
in the original appliance.
• The Pendulum springs should be activated primarily by a
derotational bending of the distal ends, as with a conventional
palatal bar. After distalization is complete, the terminal ends of
the springs should be deactivated to allow a passive fit in the
lingual molar sheaths.

SCUZZO JCO 2000 April
• A further modification of the MPendulum appliance was made by
using removable TMA arms that can be
reactivated outside the mouth.
Fabrication and Activation
The modified appliance is fabricated as
follows:
• Double over two 7-9mm lengths of .
032" TMA wire to form bayonets.
Attach each bayonet to an M-Pendulum
arm, either by using a laser welder or
by wrapping .010" ligature wire around
the arm and soldering the unit together
with silver wire and a miniflame.


• Embed each bayonet in
the soft acrylic that will be
used to form the Nance
button, producing sheaths
in which to insert the
removable arms
• Activate the arms as
desired on the working
cast


• Place the appliance in the mouth,
inserting the terminal ends of the arms
into the lingual molar band sheaths
• The removable arms can be
reactivated during treatment without
debonding and rebonding the occlusal
rests of the Nance button. Distal molar
movement can then be more precisely
controlled than by opening the
horizontal loops in the mouth. The
conventional Pendulum or MPendulum produces about 5mm of
distalization in three to four months.
With the removable arms, distal
movement can be continued at a rate
of about 1.5mm per month for as long
as necessary

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Advantages
Dramatic reduction in chair time.
Sound biomechanical principles, producing more
precise and predictable results.
Less chance of unwanted side effects.
Easy replacement of Pendulum springs without
refabrication of the entire appliance.
Ability to replace the active arms with passive
stainless steel auxiliaries after distal movement, thus
producing a “quick” Nance appliance for
stabilization.

STUDIES EVALUATING PA
• Ghosh and. Nanda. (AJO 1996)
• Friedrich K. Byloff (1997 AO) part 1 & Part 2
• Bussick & McNamara, AJO 2000March


Ghosh and. Nanda. (AJO 1996) evaluated the effect of Hilgers PA
on 41 patients , mean age 12 years and 5 months.

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DENTAL EFFECT
Sagittal Plane
The correction of the Class II relationship was achieved by a mean
maxillary first molar distalization of 3.37 mm. Average distal
tipping of 8.36°occurred in 1st molar.
The second molar teeth were distalized to a mean of 2.27 mm,and
tipped distally 11.99°.
There was a statistically significant correlation between the
amount of distalization and the amount of first molar tipping.
Vertical plane
The vertical change in molar position was insignificant. There was
a mean intrusion of 0.47 mm in second molar position

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Transverse plane
The transverse width at the maxillary second premolars increased
by 1.95 mm as they drifted distally into a wider part of the arch.
The arc described by the spring during its distal movement causes
a mesiobuccal rotation instead of distobuccal rotation. The width
between the mesiobuccal cusps of the right and left first molar
teeth increased by 1.40 mm, whereas that between the distobuccal
cusps showed no increase. The second molar teeth also showed an
expansion of 2.33 mm between the mesiobuccal cusps.
Distalization of the maxillary first molars with this appliance
therefore causes both distal as well as buccal tipping of the second
molars.
The effect of distalization on the maxillary third molars was
extremely variable. The third molars showed a net distal tipping of
2.49°, but an insignificant amount of horizontal or vertical change
in position 0.19 mm distalization and 0.22 mm intrusion

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Anchorage loss & effect on anterior segments
Loss of anchorage was measured at the first premolar teeth. For
every millimeter of distal molar movement, the premolar
moved mesially 0.75 mm.
The overjet increased by 1.30 mm and the overbite decreased
by 1.39 mm as a result of treatment. The maxillary central
incisor was proclined an average of 2.40° relative to the SN
line.
The upper lip protruded 0.31 mm and the lower lip protruded
0.95 mm relative to the E plane.
Effect of eruption of the maxillary second molar
This study indicates that the eruption of maxillary second
molars had minimal effect on first molar distalization.


Skeletal effects with the pendulum appliance :
• The pendulum appliance caused insignificant changes
in the cant of the palatal and occlusal planes. The
mandibular plane, on the other hand, showed a small
backward rotation of 1.09° with treatment, which
caused a decrease in the overbite by 1.39 mm.
• Because there was no vertical change in the maxillary
molar position and only an extrusion of 0.5 mm in
mandibular first molar position, most of the backward
mandibular rotation was caused by distalizing the
maxillary molar "into the wedge." The lower anterior
face height, as a result, increased by 2.79 mm.

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Effect based on MPA
The patients in the sample were arbitrarily divided into
three groups, based on their initial Frankfort horizontal
to mandibular plane angle (FMA) measurements.
There was a trend for greater increase in FMA in group
with FMA greater than 25°.
Patients with high mandibular plane angles showed
posterior mandibular rotation and increase in lower face
height, 4.13 mm as compared to 1.97 mm in average
MPA group.
The increase in the lower face height as a result of molar
distalization, was more than double in high angle group
(4.13 mm) than in average group (1.97 mm).

Friedrich K. Byloff (1997 AO) part 1 studied,
the dental and skeletal effects of the pendulum
appliance, applying 200 to 250 g of force to
the molars in 13 patients (age range 8 years to
13 years 5 months) by means of cephalometric
radiographs.
• This study suggest that the pendulum
appliance is effective in moving the maxillary
first molars distally at a mean monthly rate of
1.02 mm using an initial force of 200 to 250 g
in a mean period of 4 months.

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Distal molar movement, molar and incisor tipping:
The pendulum appliance produces 3.39 mm ±1.25 mm distal
molar movement with a mean bimolar intrusion of 1.17 mm ±
1.29 mm. This positive finding can be related to prevention of
dentoalveolar vertical growth by the rigid bonded appliance.
Molar distal tipping of 14.5° ± 8.33° occurred. The trajectory
of the TMA springs may account for the excessive tipping
found in this study.
Maxillary expansion is possible for transverse deficiencies in
combination with distal molar movement.
The pendulum appliance does not create dental or skeletal bite
opening.
Anchorage loss: Second premolar anchorage loss found in this
study was 1.63 mm (±1.37 mm) i.e. 29 %. Distal molar
movement represented 71% of the space opened between
molars and premolars. Incisor anchorage loss was minimal

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Friedrich K. Byloff (1997 AO) part II
In this study, the appliance was modified by
incorporating an uprighting bend into the distalizing
spring during the second phase of treatment to avoid
excessive distal tipping of the maxillary molars.
Treatment changes were analyzed and compared with
the previous study.
Due to the initial moderate dental transverse
deficiency, 8 of the patients required maxillary
expansion of 2 to 4 mm.
Appliance design and activation:
The major difference was the incorporation of the
molar uprighting bends. An expansion screw was
added to the PA in 8 of the subjects who required 2 to
4 mm of transverse development; the appliance was
activated every seventh day to achieve a slow rate of
expansion.

• Active treatment in this study, contrary to the previous one,
consisted of two phases.
• 1. Distal molar crown movement: Molar distalization was done
until an overcorrected Class I relationship was obtained.
• 2. Molar root up righting: The appliance was modified by adding a
bend to the spring design to upright the molars by moving the roots
distally. In order to make the uprighting bends, the angle between
the recurved end of the spring, which is engaged into the palatal
molar sheaths, and the long arm of the spring was increased
intraorally in the sagittal plane 10° to 15°, using a Weingart plier.
The moment created was expected to upright the molars. The
springs were left slightly active in the sagittal plane to maintain the
position of the molar crowns. The appliance was left in place until
the molar crown seemed to be sufficiently uprighted.

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Treatment time
Mean total experimental time using the PA was 27.25 ± 7.12
weeks (6 months 3 weeks ± 7 weeks).
1st phase of treatment, ( obtaining a super Class I relationship)
the distal movement phase, took 16.45 ± 6.67 weeks.
2nd phase -- to upright the maxillary molars required another
10.9 weeks.
Thus the total treatment time was increased by 64.1%.
Distal molar movement & molar tipping:
The percentage of molar movement compared with total space
opening decreased from 70.92 % to 64.16.
Rate of movement was between 0.69 mm ± 0.29 mm and 1.20
mm ± 0.74 mm per month, depending on the rate of uprighting.
For 6.07° ± 5.15° of final molar tipping, rate of movement was
0.69 mm ± 0.29 mm per month.
During the uprighting phase, the average monthly distal
movement of the apex was 1.01 mm ± 0.57 mm.

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Second molar eruption stages
In both study the position of the second molars didn’t influence
the amount of distal molar movement or premolar or incisor
anchorage loss.
Intrusion—extrusion
Increases in the premolar and incisor extrusion and decrease in
molar intrusion when compared with the first study might be a
result of the vertical reactive component of the uprighting bend.
Anchorage loss
The price for more space opening and distal molar crown
movement, and especially for more root movement and reduced
final tipping of the molars, was increased total treatment time
and 0.61 mm more anchorage loss at the premolars and 0.62 mm
at the incisor edge level.
The effects of the original pendulum appliance were not
significantly changed by the incorporation of the uprighting
bends, although slightly more anchorage loss was noted on the
maxillary incisal edge.

Bussick & McNamara, AJO 2000March
• Subjects were: Varying facial patterns (high, neutral,
and low mandibular plane angles).
• Cephalometric radiographs obtained from 13
practitioners were used to document the treatment of
101 patients (45 boys and 56 girls).
• The relative effect of erupted maxillary second
molars on distalization of the first molar and the
effects, if any, of permanent versus deciduous
dentition based anchorage on distalization of
maxillary molars were also evaluated.
• Treatment with a pendulum/pendex appliance, similar
to the type described by Hilgers,was initiated in all
patients

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Treatment effects:
1. An increase in overjet was shown.
2. The average maxillary first molar distalization was 5.7 mm, with a distal tipping
of 10.6°.
The maxillary first molars intruded 0.7 mm, and the first premolars extruded 1.0
mm.
The maxillary molar distalization contributed to 76% of the total space opening
anterior to the maxillary first molar, whereas 24% was due to reciprocal anchorage
loss of the maxillary premolars.
3. Anchor teeth
Second premolar moved mesially by the 1.8-mm with a mesial tipping of 1.5°.
The maxillary central incisors proclined slightly during treatment.
4. Second deciduous molars vs second premolar anchorage :
A. The reduction in overbite was significantly greater in the second premolar group
(average –1.5mm) than in the second deciduous molar group (average –0.3mm).
B. Patients with erupted second premolars demonstrated significantly greater
increases in lower anterior facial height (2.4 ± 1.3 mm) than did second deciduous
molars (1.6 ± 1.5 mm).
These changes are related to a downward and backward rotation of the mandible.

5. Presence or Absence of Erupted Permanent
Maxillary Second Molars
• 1. No significant differences were noted in the
anteroposterior movement of the maxillary first
molar and sagittal anchorage loss between the 57
patients who had erupted maxillary second
molars and the 44who had not.
• 2. In patients with erupted maxillary second
molars, there was a slightly greater increase in
lower anterior face height and in the mandibular
plane angle and a slightly greater decrease in
overbite in comparison to patients with
unerupted second molars.

6. Variation in Facial Patterns:
• Lower anterior facial height increased 2.2 mm;
there was no significant difference in lower anterior
facial height increase between patients of high,
neutral, or low mandibular plane angles.
• For maximum maxillary first molar distalization
with minimal increase in lower anterior facial
height, this appliance appears to be best used on
patients with maxillary second deciduous molars for
anchorage and the absence of erupted permanent
maxillary second molars, although significant bite
opening was not of major concern in any patient in
the study.

Distalization appliances based on NiTi wires
and coils
• Superelastic coils
• Superelastic archwire: single looped,
double looped


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1. SUPER ELASTIC NiTi COILS
Anthony A. Gianelly (AJO 1991) used Japanese NiTi
super elastic coils, exerting 100 gm of force,
compressed against the maxillary first molars and
moved the molars distally 1 to 1.5 mm/month.
Coils are used in conjunction with a vertically slotted
(0.020-inch) fixed appliance.
A passive 0.016 ´ 0.22-inch wire with stops that abut
the distal wings of the premolar brackets is inserted
to ensure that the wire cannot move past the first
premolars, thus placing the reaction force on the
Nance appliance. Coils are placed on the wire between
the first premolars and the molars.
The coils are activated 8 to 10 mm by compressing
and maintaining them against the molars by crimpable
hooks or Gurin locks.

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Anchorage
A Nance-type appliance was cemented onto the first premolars.
The appliance extends from the incisors to the molar area and a
bite plate is added to the incisal portion to disclude the posterior
teeth slightly
Anchorage enhancement:
To enhance anchorage further, a 0.018-inch uprighting spring is
placed in the vertical slot of the premolar brackets, directing the
crowns distally.
Class II mechanics are used only when anchorage loss is at least
1 mm.
When Class II elastics are attached, a rectangular wire with 10°
of incisor lingual root torque is inserted in the mandibular arch
to maintain lower incisor position.
100 gm superelastic coils can be used successfully in patients
with Class II malocclusions to move molars posteriorly at the
rate of 1 to 1.5 mm/month with little or no cooperation from the
patient.

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SUPER ELASTIC NiTi WIRES
The use of shape memory, superelastic Nickel Titanium wires
in
distalizing the molars have been discussed by Ranieri & Antony
A.Gianelly in 1992.JCO
FABRICATION
Gianelly used a superelastic NiTi arch wire here.
1. A 100 gm Neosentalloy wire with regular arch form is placed
over the maxillary arch. The superelastic NiTi wire is an 0.018
X 0.025 inch wire that also applies 100 gm of force.
The wire is then marked in three places on each side.
A. At the distal wing of the first premolar bracket.
B. 5-7 mm distal to the anterior opening of the buccal tube
C. Between the lateral incisors and canines

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A stop is then crimped on the arch wire at each of the posterior
marks and a hook is then added for inter-maxillary elastics
between the lateral incisors and canines.
3. The wire is then inserted into the molar tube until the
posterior stop abuts the tube.
• To place the wire through the first premolar bracket, the anterior
stop is grasped and the wire gently forced distally so that the
stop abuts the distal wing of the first premolar bracket, when
ligated.
• Since the wire is 5-7 mm longer than the available space, the
excess will be deflected gingivally into the buccal fold.

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ACTION OF THE WIRE/APPLIANCE
The distalization of the molars occur as the wire returns to its original shape,
exerting a distal force of 100 gms against the molars and a reactionary
mesial force on the first premolars, canines and incisors.
There is also a tendency for the premolars to move buccally.
THE ANCHORAGE
The anchorage can be controlled by
a. Placing a 100-150 gm class II elastics against the first premolars. (or)
b. Placement of hooks between the lateral incisors and canines (or)
c. A Nance appliance cemented to the first premolars.


THE ADVANTAGE OF THE APPLIANCE
• 1. The appliance distalizes the molar at the rate
of 1-2 mm per month with little loss of
anchorage.
• 2. The Neosentalloy wire is easy to insert even
after all teeth have been bracketed or banded.


Giancotti, & Cozza (JCO 1998 April) used double loop for
simultaneous distalization of both molars
• Superelastic nickel titanium wires have been found as effective
as other means in producing distal movement of the maxillary
first molars. When the distalization is carried out before the
second molars have erupted, it can reliably produce 1-2mm of
space. Once the second molars have erupted, however, the distal
movement can be more difficult and time-consuming, and loss of
anchorage is likely.
Author used Nickel Titanium Double-Loop System for
Simultaneous distalization of First and Second Molars.
Appliance Design
• The mandibular first and second molars and second bicuspids
are banded, and the remaining mandibular teeth are bonded. A
lip bumper is placed to prevent any extrusion from the use of
Class II elastics.
• The maxillary molars and bicuspids are banded, and the anterior
teeth are bonded

• An 80g NeoSentalloy archwire is
placed on the maxillary arch and
marked distal to the first bicuspid
bracket and about 5mm distal to
the first molar tube . Stops are
then crimped in the archwire at
each mark (distal to 4 and 6)
• Two sectional nickel titanium
archwires (one for each side) are
prepared by crimping stops distal
and mesial to the second
bicuspids and about 5mm distal to
each second molar tube.
• Uprighting springs are inserted
into the vertical slots of the first
bicuspid and Class IIwww.indiandentalacademy.com
elastics are
placed

JONES JIG APPLINCE
• Introduced by Jones & White in 1992.
• Jones Jig uses an open-coil nickel titanium spring to deliver 70-75g
of force, over a compression range of 1-5mm, to the molars.
Appliance Fabrication
• A modified Nance appliance provides anchorage for the use of the
Jones Jig.
Modification in Nance:
• It can be attached to the first bicuspids, second bicuspids, or
deciduous second molars.
The appointment sequence is as follows:
• Appointment 1 : Separators are placed between the first molars and
the anchor teeth.
• Appointment 2 :Impression is made with bands. Pour the impression
with the bands in stone.
A .036" stainless steel wire is adapted to the palate on the cast,
extending it as far as the canines, and soldered to the anchor bands.

The Jones Jig assembly consists of a mainframe of two prescriptions
(0.018 & 0.22 inches respectively), which can be contoured in the
anterior one third. It also consists of a mainframe hook which is
tied to the hook of the molar tube. The force is delivered by a
Nickel Titanium coil spring, which acts along the mainframe wire,
when activated using a ligature. A 0.014 inch ligature wire is
generally used to fasten the eyelet tube to the premolar bracket,
which compresses the NiTi coil springs. The distal end of the
mainframe consists of a keeper wire (0.018 inch) which goes into
the archwire slot and a mainframe wire which enters the head gear
slot of the molar tube. The extreme mesial end of the completed
assembly should rest no further than the distal 1/3rd of the
bicuspid.

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ACTIVATION
A 0.014 inch ligature wire is wound around the buccal tube and
the mainframe hook very lightly. Then a 0.012 inch-ligature
wire is wound twice around the premolar bracket and the
mesial end passed through the eyelet tube. The ligature wire is
then tightened until 'light' through the middle of the open coil is
barely seen.
Bunching or over activation of the coil spring should the
avoided as it can lead to unwanted tipping and palatal
irritation along the palatal button.
Although the force of the Jones Jig is applied in a Class I
direction, the appliance may be contraindicated in cases of
extreme vertical growth patterns, because extrusion of the
molars is not restricted.
REACTIVATION
Reactivation takes very little chair time and is due over a
period or four to five week intervals.

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TREATMENT TIME
In Pseudo class II where it is the rotated class I which
needs to be corrected, the treatment time is 90-120
days.
In true class II molar relationships, the corrected class
I relationship can be achieved in 120-180 days.
However the treatment time is slightly increased in
brachyfacial patterns.
Drawback:
The use of the Nance appliance causes palatal tissue
impingement.
Laboratory expense
Extra appointment needed to fit the Nance appliance.
Coils demand extra diligence in cleaning

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Comparison of Jones jig molar distalization appliance with
extraoral traction
Seda Haydar (AJO 2000 Jan)
20 patients in late mixed dentition period with skeletal Class I or
slight Class II malocclusions, with dental Class II relationship
were treated with Jones jig and headgear.
Ten cases were treated with the Jones jig appliance for upper
molar distalization, and 10 patients used cervical headgear for
correction of dental Class II relationship.
The mean age was 10.6 and 10.7 years, respectively, for headgear
and Jones jig group.
Long cervical face bows were used, and the outer bows were
parallel to the occlusal plane exerting 600 g of force with an
average use of 16 hours per day until a Class I molar relationship
was reached. Average treatment time for distalization with
headgear was 10.7 months followed by a fixed appliance phase of
11 months.

• In the Jones jig group, the spring was activated at 4 week
intervals and 75 g of force was applied because 5 mm of
activation was made at each visit. A modified Nance appliance
was used as an anchorage unit. The average treatment time to
move molars distally was 2.5 months. After distalization of
molars, fixed appliance therapy was applied to each patient
and total treatment time was 15.1 months.
Skeletal change:
• In the headgear group the decrease in SNA angle was found
statistically significant, downward tipping of palatal plane was
also found statistically significant.
• On the other hand, none of these effects occurred in the Jones
jig treatment group.
• In this study, no increase was observed in GoGnSN angle in
both groups.

Effect on molars and premolars
• In the headgear group, the distalization of maxillary
first molars and maxillary second premolars was a
consistent finding
• In the Jones jig group, the distalization and distal
tipping of maxillary first molars and mesial
movement of premolar occurred.
• Extrusion of maxillary first molars was observed in
both groups, but it was found statistically significant
only in Jones jig group.


• Jones jig group, showed mesial tipping of the
anchorage unit, this is contrary to the finding in the
headgear group in which spontaneous distalization
of premolars was observed as a result of the
distalization of molar teeth.
Effect on Incisors
• Headgear group, showed the extrusion and retrusion
of incisors that might occur as a result of the
retraction effect of headgear on anterior teeth.
• Jones jig group showed protrusion of the incisors
because the incisors were part of the anchorage unit

Average treatment time
• The average treatment time for molar correction
with headgear and Jones jig was 10.7 and 2.5
months, respectively. Because intraoral distalization
moves molars distally in a very short time, total
treatment time is reduced by at least 6 to 8 months
despite the fact that the anterior teeth move or tip
mesially during molar correction. Although a distal
drift of premolars take place during distalization,
this does not reduce the total treatment time because
treatment may cease at times when headgear
cooperation is poor.
• Intraoral distalization seems more appropriate for
regaining space for cases in which no orthopedic
effect is desired on the maxilla as with skeletal Class
I or borderline Class II patients.

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Brickman, & Nanda ( AJO 2000 NOV) evaluated the effects of
the Jones jig appliance on distal movement of maxillary molars
and reciprocal effects on premolars and maxillary incisors.
Measurements were made on a matched sample of 35 patients
treated with cervical headgear and compared with result of 72
patients treated with Jones jig.
Both series of patients were treated to correct an Angle Class II
molar relationship.
The results from the Jones jig sample showed
Mean maxillary first molar distal movement was 2.51 mm &
distal tipping of 7.53°.
The mean reciprocal mesial movement of the maxillary
premolar was 2.0 mm and mesial tipping of 4.76°.
The maxillary first molar extruded 0.14 mm & the maxillary
premolar extruded 1.88 mm
The maxillary second molars were also moved distally 2.02
mm and tipped distally 7.89°.

• The Jones jig sample demonstrated effective distal
molar movement and maintenance of the Class I
molar relationship. Cervical headgear sample showed
treatment results comparable with Jones Jig.
• The longitudinal assessment showed significant
differences between the Jones jig sample and the
cervical headgear sample for lower lip to E-line and
SNA.
• 1. The Jones jig sample showed a mean decrease in
lower lip to E-line of 0.25 mm versus 1.20 mm for the
headgear sample.
• 2. SNA decreased 0.40° for the Jones jig sample
versus 1.20° for the headgear sample.

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DISTAL JET
Distal jet was designed by Aldo
Carano & Mauro in 1996.
Appliance Design
Bilateral tubes of .036" internal
diameter which is attached to an
acrylic Nance button.
A NiTi coil spring and a screwclamp are slid over each tube.
The wire extending from the
acrylic through each tube ends in
a bayonet bend that is inserted
into the lingual sheath of the first
molar band. An anchor wire from
the Nance button is soldered to
bands on the second premolars

1.

TP connector
6. Activation lock

2. Bayonet director

7. C Res
3. Molar bayonet
Components:
• 1. The Transpalatal connector – rigidly immobilizes the premolars and provides
a support to the Nance button.
• 2. The bayonet director unit - Lumen of the tube portion supports the molar
bayonet, while its outside diameter supports the spring and the activation lock.
• 3. The molar bayonet - It is drawn out of the bayonet director unit during
distalization and inserts into the lingual sheath.
• 4. The Distal stop - Prevents the spring from riding up on the vertical arm of
the molar bayonet while activation of the appliance.
• 5. Nickel titanium springs - Two force ranges - 180 gms and 240 gms.
• 6. Activation locks - To compress and activate the springs.
• 7. Lock wrench - To engage and tighten the screw of the activation lock

Activation:
• The Distal Jet is reactivated by
sliding the clamp closer to the
first molar once a month.

• Once distalization is complete,
the appliance can be converted
to a Nance retainer simply by
replacing the clamp-spring
assemblies with cold-cure
acrylic and
cutting off the arms to the
premolars.

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Advantage of distal jet :
The appliance is relatively easy to fabricate,
easy to insert, is well tolerated and is esthetic.
Easy activation
Ease of conversion to a Nance holding arch to
maintain the distalized molar positions.
The Distal Jet also permits the simultaneous
use of full bonded appliances, possibly
avoiding the need for two phases of treatment

MODIFICATIONS OF DISTAL JET
• Bowman (1998 Sept JCO) described several
modifications to the original appliance.
• Conversion to Nance Holding Arch:
Upon completion of molar distalization, the Distal Jet is
converted to a Nance holding arch to prevent further
distal movement and consequent anchorage loss. It can
be done by these two methods:
• 1. One way to stop movement of the bayonet wire
through the tube is to flow a light-cured acrylic around
the coil spring, over the distal bayonet bend, and over
the activation collar to produce a solid extension from
the molar bands to the acrylic button.

• 2. Wrap an .014" stainless steel ligature wire around
the end of the doubled back wire (extending distally
from the lingual sheath on the first molar band) and tie
it around the tube just mesial to the activation collar.
The coil spring should be compressed completely and
the set screw tightened to prevent mesial movement of
the molars.

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Double -Set -Screw Distal Jet
A modification of the Distal Jet
incorporating two set screws into the
activation collar permits an easier,
cleaner, and more reliable conversion to
a molar Nance holding arch.
The mesial set screw is used during
active distalization .The distal screw is
set on the bayonet wire, locking the two
pieces together to prevent molar
movement.
The premolar supporting wires are
sectioned where they enter the acrylic
button, using a high-speed handpiece
and diamond bur.
The bayonet wire or tube can be bent
with a three-prong plier to adjust the
pressure of theacrylic button against the
palate

Conversion of double-set-screw Distal Jet to Nance holding arch:
A. Upon completion ofmolar distalization, double-set-screw
activation collar is slid mesially to gain access to coil spring.
B.Free end of coil spring is grasped with plier. Coil spring is
removed by peeling it away from bayonet wire.
C. Distal end of tube, where bayonet wire enters, can now be seen.
D. Double set-screw collar is slid back to this junction, mesial set
screw is locked on tube, and distal screw is set on bayonet.

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Quick & Angela Harris (JCO 2000 July)
The Distal Jet is a fixed palatal appliance that is most
commonly used to distalize the maxillary molars,
either unilaterally or bilaterally.
Disadvantage of Distal jet: Lies in activation
The appliance is activated by sliding a collar along the
supporting tube to compress a coil spring, then fixing
the collar in place by tightening a small set-screw.
This procedure is sometimes difficult because of the
small size of the screw, the moisture and confined
space of the intraoral environment, and food
impaction in the screw head.
In addition, activation requires the use of a small Allen
wrench, which has the risk of being swallowed or
aspirated.

Appliance Design
• The basis of the modification is the rear
entry of the sliding section into the
lingual molar sheath, so that the
appliance pulls rather than pushes the
molars distally. The doubled-backwire
(or “foot”) is inserted into the lingual
sheath from the distal. The foot should
be a little longer than the sheath so it
can be tied back to the sliding section
with an elastomeric or metal ligature.
• Either .030" or .032" wire is suitable for
the sliding sections. Support tubes of
corresponding internal diameter are
embedded in the acrylic Nance button.
The desired amount of activation is
achieved by compressing the coil spring
between the distal end of the support
tube and a stop soldered to the sliding
wire.


• To reactivate the appliance, the safety ligature
is cut, the sliding wire is pulled out distally,
and a new, longer section of coil is placed over
the wire.
• In addition, no set-screws or Allen wrenches
are used, simplifying the activation procedure.
• After molar distalization is completed, the
molar positions are held by replacing the open
coils with either closed coils or solid tubing to
prevent anterior relapse or a new Nance button
can be made.

THE FIXED PISTON APPLIANCE
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The appliance was described by Raphael
U.Greenfield in 1997.
The appliance proposed to achieve distal
bodily movement of the molars without
tipping the crown with no loss of posterior
anchorage.
THE APPLIANCE
The components of the appliance are:
a. Maxillary first molar and first bicuspid
bands.
b. 0.036" stainless steel tubing (soldered to
the bicuspids).
c.0.030" stainless steel wires (soldered to
the first molar).
d. Enlarged Nance button reinforced with
an 0.040" stainless steel wire for control of
anterior anchorage.
e. 0.055" hyperplastic nickel titanium opencoil springs - to provide a light but
continuous force.

•
•

•
•

•

Fabrication
1. The first molars are banded with a
double or triple tube.
2. The first / second bicuspids are
then banded. Normally the buccal
and lingual piston assemblies should
extend to the embrasure of the cuspid
and first bicuspid to be long enough
for adequate distalization.
In maximum molar distalization
however, the piston assembly may be
extended beyond the first bicuspids.
3. A full arch silicone/vinyl
impression is then taken such that the
bands seat securely in the
impression.
4. The bands are then waxed and a
working cast in stone is made.

• 5. A 0.040" stainless steel wire is then adapted to the palate and
is brought posteriorly to the gingival third of the bicuspid for
soldering.
• 6. A 0.036" stainless steel tubing is then soldered to the buccal
and lingual occlusal thirds of the bicuspid bands.
• 7. The 0.030" stainless steel wire is soldered to the buccal and
lingual surfaces of the first molar bands. 0.040" stainless steel
Nance wire is then soldered to the bicuspid bands.

• The piston assemblies must be
parallel in both the occlusal and
sagittal views.
• A slight palatal cant from distal to
mesial can however be given to
prevent occlusal displacements of
the palatal acrylic.
•

A 2mm split ring stop is than
added to the mesial of the buccal
and lingual tube on each piston
assembly every 6 to 8 weeks. This
provides around 25 gms of force to
each piston assembly which works
out to 50 gms per tooth.

•
•
•
•
•
•

•

THE ADVANTAGES
The fixed piston appliance has been proved to be effective in
molar distalisation and is said to have the following
advantages:
Bodily movement of maxillary first molars (with no loss of
posterior anchorage).
Minimum patient compliance.
Allows the use of head gear if needed.
In non-extraction cases, it is proved to reduce treatment time as
it distalizes at the rate of 1mm per month.
Maintains the arch width after expansion with Haas or Hyrax
appliances.
Uses a light, controlled force of only 1-2 ounce per tooth.
Because of this there is no loss of anterior anchorage and no
inflammation of the palatal mucosa beneath and adjacent to the
modified Nance button.
Does not interfere with the occlusal plane, thus maintaining
effective control over the vertical dimensions.

•
•

•
•
•

IBMD
Ahmet Keles¸AJO (Jan 2000)
15 patients were treated with IBMD , their average
age was 13.53 years old ranging from 11 to 16 Years
old. Second molars were present in all the cases.
Appliance Construction
The intraoral bodily molar distalizer (IBMD was
composed of 2 parts: the anchorage unit and the
distalizing unit.
The anchorage unit was a wide Nance button, and the
active unit consisted of distalizing springs
The springs had 2 components: the distalizer section
of the spring applied a crown tipping force, while the
uprighting section of the spring applied a root
uprighting force on the first molars.

• Maxillary first molars and premolars were banded. On the
palatal side of the first molar bands, 0.032 × 0.032 inch slot
size hinge cap palatal attachments were welded, and a
maxillary impression was taken. On the model, a wide
acrylic Nance button was constructed and attached to the first
premolar bands with 0.045 inch in diameter stainless steel
retaining wires.
• The acrylic button was constructed that functioned as an
anterior bite plane to disclude the posterior teeth and enhance
molar distalization.
• For molar distalization 0.32 x 0.32 inch size TMA springs
were bent and oriented from the acrylic. The springs had 2
components. The distalizer section of the spring applied a
crown tipping force, whereas the uprighting section of the
spring applied a root uprighting force to the first molars

B. The intraoral bodily molar distalizer (IBMD) was cemented to
the first premolars without the springs engaged.
B. After the cementation, the hinge caps on the molar bands were
opened.
C. Activation of distalizing component
D. Activation of the springs was accomplished by pulling from
distal to mesial with the help of a Weingart plier and then
seating into the slot of the palatal hinge cap attachments. It
applied a total of 230 g of distal force.

• This study showed that maxillary 1st molars were distalized bodily
5.23mm on average. Maxillary molar extrusion was not observed
after distalization. Maxillary molars did not rotate and intermolar
distance did not change after distalization.
• Class I molar relationship was achieved in an average period of 7.5
months.
• Maxillary first premolars moved forward 4.33 mm, were extruded
3.33 mm, and tipped 2.7° distally.
• A 4.77 mm protrusion and 6.73° proclination of the incisors were
observed.
• The overjet was increased by 4.1 mm; whereas the overbite was
reduced by 2.63 mm. Mandibular first molars were extruded by
1.53 mm.
• After the removal of IBMD, incisor protrusion and mesial
migration of premolars spontaneously relapsed distally


Skeletal change:
• Mandibular plane angle increased by
1.26°.
• Anterior lower face height to total face
height ratio was increased by 0.95 mm.
• SNA increased by 1.56°, whereas ANB
angle increased by 1.66°.


K-Loop
Put forward by Valrun Kalra (JCO 1995)
The K-Loop molar distalizer consists of
• 1. A K-Loop to provide the forces and
moments.
• 2. A Nance button - to resist anchorage.
• The k-Loop is made of 0.017’ x 0.025' TMA
wire which can be activated twice as much as
stainless steel, before it undergoes permanent
plastic deformation.

A

B

C

A. The loop of the 'K' should be 8 mm long and 1.5 mm
wide.
B. The legs of the 'K' are to be bent down 20 ° and
inserted into the molar tube and the premolar bracket.
C. The wires are marked at the mesial of the molar tube
and the distal of the premolar bracket.

D

E

D. Stops are bent into the wire 1 mm distal to the distal
mark and 1 mm mesial to the mesial mark. Each stop
are well defined and are about 1.5mm long.
E. These bends help keep the appliances away from the
mucobuccal fold, allowing a 2mm activation of the
loop

• The bends in the appliance legs produce moments that
counteract the tipping moments created by the force of
the appliance, and these moments are reinforced by
the moment of activation as the loop is squeezed into
place. Thus, the molar undergoes a translatory
movement instead of tipping. Root movements are
said to continue even after the forces dissipate.


• For additional molar movement, the reactivation is
2mm after 6 to 8 weeks.
• The premolars move forward by 1 mm during 4 mm of
molar distalization (the anchorage loss). To prevent
anchorage loss a head gear (straight pull or high pull)
with forces of 150 g to the premolars can be used.
Advantages
• Simple & efficient
• Controls moment to force ratio to produce bodily
movement
• Easy fabrication and placement
• Hygienic and comfortable to the patient
• Low cost.

First class appliance Jco 99 June
• Bands are placed on the
maxillary first molars and
on either the maxillary
second premolars or the
second deciduous molars.
• Impressions are taken
with these bands in place,
and a working cast is
poured.

Vestibular components: Formative
screws are soldered on the buccal
sides of the first molar bands,
occlusal to the .022" × .028"
single tubes, so they will not
interfere with subsequent insertion
of the archwire .
• Split rings, welded to the second
premolar or second deciduous
molar bands, control the vestibular
screws.
• Stop screws are used to maintain
the distal positions of the molars
after active movement has been
completed.

2. Palatal components. In the palatal aspect, the appliance is much
like a modified Nance button, but is wider and has a butterfly
shape for added stability and support during retention . The
butterfly section is soldered to the second bicuspid or deciduous
molar bands.
The embedded .045" wires should be in single sections, without
welded joints, to prevent breakage. Sections of .045" tube are
soldered to the palatal sides of the first molar bands for insertion
of the butterfly component of the appliance. These tubes allow
the molars to be distalized without undesirable tipping.

Nickel titanium .010" × .045" coil springs,
approximately 10mm each in length, are fully
compressed between the bicuspid solder joints and
the tubes on the deciduous molar or second bicuspid
bands. These springs are designed to balance the
action of the vestibular screws, preventing molar
rotations and development of posterior crossbites.

• Bodily distalization of first molars on both sides;
detail of formative screw at end of activation


• Fortini et al (AJO 2004 June) evaluated the treatment effects of
FCA on 17 patients.
• The FCA produced rapid molar distalization: bilateral Class II
molar relationship was corrected in 2.4 months on average. The
maxillary molar distalization contributed to 70% of the space
created anterior to the first molars: 30% was due to reciprocal
anchorage loss of the maxillary second premolars.
• The maxillary first molars were moved distally an average of
4.0 mm per side with a mean distal tipping of 4.6°. Rate of
distalization was 1.7mm / month.
• Anchorage loss measured at the second premolars was1.7 mm
with 2.2° of mesial tipping.
The maxillary central incisors proclined slightly during
treatment (2.6°) with minimal increase in Overjet (1.2 mm).
No significant changes in sagittal or vertical skeletal
relationships were observed.

Carriere Distalizer
• LUIS CARRIERE (JCO 2004 April) developed a new Class II
distalizer with advanced computer technology.
• Brachyfacial patterns respond best to treatment; dolichofacial
types are less responsive. Growing patients are ideal, but adults
can be treated as well. Mixed dentition Class II cases with fully
erupted first molars are candidates for first-phase treatment.
Biomechanics:
• The Carriere Distalizer is designed to create a Class I molar and
canine relationship. The biomechanical objectives of the
appliance are as follows:
• 1. Produce a distal rotational movement of the maxillary first
molars.
• 2. Produce a uniform force for distal molar movement.
• 3. Independently move each posterior segment, from canine to
molar, as a unit.

Appliance Design
• The Distalizer is made of mold-injected, nickel-free stainless
steel. It is bonded to the canine and first molar as follows:
• The canine pad, which allows distal movement of the canine
along the alveolar ridge without tipping, provides a hook for
the attachment of Class II elastics. This pad is the mesial end
of an arm that runs posteriorly over the two upper premolars
in a slight curve.
• The posterior end of the arm is a permanently attached ball
that articulates in a socket on the molar pad.

• The ball and socket joint provides torque (3D) control of both the
canine and molar
• The posterior portion of the Distalizer accomplishes three types of
molar movement:
• 1. Uprighting of the crown, if it is mesially in-clined .Once the
molar has been upright-ed; the articulation of the ball with the
socket prevents distal tipping.
• 2. Distal rotation around the palatal root. When the molar has been
derotated, the shoulder of the posterior base contacts the mesial arm
to prevent over rotation.
• 3. Distal displacement without concurrent distal tipping of the
crown

• Appliance Placement
• The Distalizer comes in three
sizes: 23mm, 25mm, and 27mm.
The appropriate size is determined by measuring from the
midpoint of the maxillary first
molar's buccal surface to the midpoint of the maxillary canine
crown, using a caliper or the
supplied Dentometer.
• In case of blocked out canines it
is bonded to 2nd molar and 1st
premolar.
• Appliance is bonded to 1st molar
and canine with a light cured
adhesive

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•
•
•
•

Possible 5 sources of anchorage:
Passive .036’ lingual arch
0.45’ SS Hamula lingual arch
Full mandibular fixed appliances
Lower Essix appliance with hooks for
elastics in lower molar region.
Miniscrews
Patient is instructed to wear heavy 6 ½ oz ,
¼ “ Class II elastics 24 hours a day, except
during meals.

BYLOFF et al (JCO 2000 sept) made a new device, based on the
Pendulum that can distalize mandibular molars without the
drawbacks of other appliances.
Appliance Design
• The Franzulum Appliance’s anterior anchorage unit is an acrylic
button, positioned lingually and inferiorly to the mandibular
anterior teeth, and extending from the mandibular left canine to
the mandibular right canine.
• Rests on the canines and first premolars are made from .032"
stainless steel wire. Tubes between the second premolars and first
molars receive the active components. The posterior distalizing
unit uses nickel titanium coil springs, about 18mm in length,
which apply an initial force of 100-120g per side

• A J-shaped wire passing through each coil is inserted into the
corresponding tube of the anchorage unit the recurved posterior
portion of the wire is engaged in the lingual sheath of the
mandibular first molar band.
• The anchorage unit is bonded with composite resin to the
canines and first premolars.
• The J-shaped distalizing unit is then ligated to the
lingualsheaths of the molar bands, compressing the coil springs.
Thus, the active part of the appliance runs lingually at a level
close to the center of resistance of the molar, to produce an
almost pure bodily movement

During the distalization phase, the
mandibular molars moved 4.5-5mm distally
while the incisors moved 1mm anteriorly.
The mandibular right molar crown tipped 4°
distally, and the mandibular incisor crowns
tipped 1° labially. Thus, the movement of the
incisor crown resulted in an anchorage loss
of 1mm and 1°.


B. Intermaxillary appliance:
1. Herbst appliance
2. Jasper Jumper
3. Eureka Spring
4. Klapper superspring


Herbst Appliance
• The Herbst appliance is completely tooth-borne and uses both
the maxillary and mandibular dentition to transfer the force
exerted from the telescopic arms of the Herbst bite jumping
mech-anism to the bases of the maxilla and the mandible. The
telescopic system produces a posterosuperiorly directed force on
the maxil-lary posterior teeth and an anteriorly directed force on
the mandibular dentition. As a result, Class II molar correction
generally is a combina-tion of skeletal and dentoalveolar
changes irre-spective of facial morphology.


The Herbst telescoping bitejumping mechanism places a
distal and intrusive force on the maxillary molars and the
force vector passes occ1usally to the center of resistance.
This force system produces backward and upward
movements of maxillary molars in conjunction with distal
crown tip-ping. Because of the intrusive effect, distal
movements of maxillary molars do not tend to open the
mandible. These effects are similar to those produced by
high-pull head-gear.
• In general, maxillary molar distal-ization has been shown to
comprise approxi-mately 25% to 40% of molar correction
with the banded Herbst appliance, whereas in the acrylic
design it accounts for 20% to 25% of the correction.
•

• The distalizing effects are reported to range from an average
of 1.8 mm in the study by Franchi et al (AJO 1999) to 2.8
mm in the study by Pancherez (AJO 1982). The intrusive
effects are 1mm approximately. The amount of distal and
vertical movement of maxillary molars is found to be
independent of the presence of erupted 2nd molar.

Stability
• In a long-term study on the results of Herbst treatment,
Pancherz (AJO 1991) compared two groups of Herbsttreated patients with and without relapse in the occlusion.
Skeletal and dentoalveolar changes in the mandibular arch
were found to be similar in both groups 5 years after
treatment. The reason for relapse was thought to be the
anterior movements of maxillary dentition owing to
muscular influence from the lips or tongue, or to an unstable
occlusal conditionwww.indiandentalacademy.com
after treatment.
•

• The Klapper Superspring II:
• In 1997 Lewis Klapper introduced the
Klapper Superspring for the correction
of Class II malocclusions. It resembles
a Jasper Jumper with the substitution of
a cable for the coil spring. In 1998 the
cable was wrapped with a coil.
• The Klapper Superspring II inserts
from the mesial and is rigidly secured
to the molar by an oval attachment
tube. The Klapper Superspring creates
a mo-ment on the molar, which is
expressed clinically as distal root tip,
but extended wear of the appliance
results in excessive distal root tipping.
•

• Because the Klapper Superspring inserts gingivally on the
molar and cannot roll to the buccal as readily as a Jasper
Jumper, there may be a greater vertical component to the
force vector. If this were of clinical significance, a patient
with a pro-nounced curve of Spee would level more
quickly with the Klapper Superspring. However, extended
wear should pro-duce excessive intrusions and may require
removal before sagittal corrections have been completed.
• Disadvantages of the Klapper Superspring:
• 1. Requirement of a special molar tube,
• 2. Limitation to maximal opening,
• 3. Risk of injury to the patient if breakage oc-curs
• 4. Extended wear may cause excessive distal root tipping to
the maxillary molar and more intrusion to the molars and
incisors than desired

• The Eureka Spring
• 1997 JCO
• The interarch Eureka Spring became
available in 1996, has a pure
compression action, and therefore
delivers linear force throughout its
range. It permits unlimited mandibular
move-ments and has good patient
acceptance. It can be used in Class II
and Class III malocclusions, does not
require molar tubes, and can be used in
conjunction with extraoral force. These
springs come in two sizes and are
converted at the time of insertion into
left or right action; therefore inventory
is minimal.

• No auxiliary attachments are required. Because it is truly a
compression spring, it is less prone to breakage than curvi-linear
than Jasper Jumper. A constant force of 16 grams per millimeter
is generated, which permits the clinician to visually determine the
force at any time and adjust the force as needed
• A cephalometric evaluation of the first 50 consecutively treated
bilateral Class II patients indicated the following:
• Average anteroposterior correction was at the rate of 0.7mm per
month.
• For every 3 mm of anteroposterior correction, the maxil-lary
molars intruded 1 mm and the mandibular incisors intruded 2
mm.


• The maxillary dentition moved distally 1.5 mm and
the mandibular dentition moved mesially 1.5 mm.
• No increase occurred in anterior face height between
the dolichocephalic and brachycephalic subgroups.
• As with the Jasper Jumper, intrusion of teeth occurs
dur-ing treatment. However, unlike the Jasper Jumper
the amount of intrusive force can be altered by
changing the force vector and magnitude

IMPLANT SUPPORTED DISTALIZATION

•
•
•

Karaman - implant-supported modified distal
jet appliance
Graz implant supported pendulum
Sugawara & Umemori SAS supported
mandibular distalization


Karaman (AO 2002 April ) A case
report
• In this study, author used an implantsupported modified distal jet appliance
that has the advantages of implants and
intraoral distalization appliances, and
assessed its effect on dentofacial
structures.
• Molar bands with palatal tubes were
fitted to the upper first molars. An
anchorage screw three mm in diameter
and 14 mm in length was placed at the
anterior palatal suture, two–three mm
posterior to the canalis incissivus
under local anesthesia .

• Anchor wires 0.8 mm in
diameter were soldered to the
tubes for occlusal rests on the
first premolars. The 0.9-mm wire
extended through each tube,
ending in a bayonet bend that
was inserted into the palatal tube
of the first molar band.
• For force application, Niti opencoil springs were adjusted.
• The implant-supported modified
distal jet appliance was attached
to the anchor premolars and
implant with light-cured
composite adhesive.

• The screw was removed without anesthesia and with no
discomfort for the patient during the removal.
• Maxillary molar moved distally 5mm after 4 months of
treatment and intruded by 2mm without movement of
premolars.
• Upper incisor position, MPA, and LAFH remained the same.
• The main advantages of the appliance are its stability against
rotational movements. Adequate distal movement of the molar
tooth was achieved without the loss of anchorage.
• Irritation of the palatal mucosa and gingival hyperplasia didn’t
occur because the patient could maintain optimum oral
hygiene.

•
•

•

•

GRAZ IMPLANT SUPPORTED PENDULUM
Byloff et al (Int J Adult Orthod. Orthognathic Surg
2000)
To avoid mesial movement of anchor teeth, extraoral
anchorage such as headgears and intraoral Nance
holding arches are commonly used.
Advances with implants have made it possible to use
them as a means of anchorage in adult orthodontic
patients.
But with orthodontic patients, when only the question
of anchorage must be addressed, the retro molar area or
the palate as implant locations are preferred because
they do not interfere with orthodontic tooth movement.

Site for Orthodontic Implants:
• The histomorphology of the palatal bone shows that
the median palatal region is the best location for an
endosseous implant.
Implant loading:
• Implants are loaded after a period of approximately 12
to 24 weeks to allow healing and osseointegration,
which seems to be a general rule in the use of
implants.
• Byloff described a newly designed palatal anchoring
system, the Graz implant-supported pendulum
(GISP) .This system can be loaded within 2 weeks to
distalize and anchor maxillary first and second molars.

The anchorage part of the GISP consists of a simple
surgical plate (15 X 10 mm) with 4 screw holes. Two
cylinders (10 mm long and 3.5 mm in diameter) are
soldered at right angles to the center of the plate.
The plate is fixed to the palatal bone via four 5-mm-long
titanium mini-screws The 2 cylinders perforate the
palatal mucosa to enter the oral cavity .The entire
anchorage device is made of 100% Titanium.

•
•

Implant is placed under GA.
Maxillary impression is taken after 2 weeks of
healing.
•
Removable PA is fabricated.
• TMA springs are activated extraorally to generate
250 g of force www.indiandentalacademy.com

Because molars tend to tip back when distalized
with a PA,an uprighting bend ( Byloff AO 1997)
was introduced into the recurved end of the spring
when necessary.
• After the 8 months of molar distalization, the first
and second premolars have drifted distally,
presumably under the influence of the elastic fibers
in that area. The molars were almost in a full Class
II relationship at the beginning of treatment


Advantages:
1. Class II elastics to support anchorage are unnecessary, and
side ef-fects on the mandible are avoided.
2. This system can be loaded almost immediately, which is
an advantage over implants requiring a healing and
osseointegration time of at least 3 – 4 month.
3. Unilateral distalization can be done without any effect of
generated moment.
4. Treat-ment time is decreased because of the anchorage
provided by the GISP. En masse retraction of anteriors can
be done shortening the treatment time considerably.
5. Stability against rotational movements
Disadvantage: Invasive surgical procedure for insertion and
removal of anchorage plates.

Sugawara & Umemori, (Ajo 2004Jan)
• The skeletal anchorage system (SAS) consists of titanium
anchor plates and monocortical screws that are temporarily
placed in either the maxilla or the mandible, or in both, as
absolute orthodontic anchorage units, Distalization of the
molars has been one of the most difficult biomechanical
problems in traditional orthodontics, particularly in adults and
in the mandible, However, it has now become possible to
move molar's distally with the SAS to correct anterior
crossbites, maxillary dental protrusion, crowding, dental
asymmetries without having to extract premolars.


Skeletal anchorage system (SAS) uses pure titanium
anchor plates and screws as absolute orthodontic
anchorage units. The anchor plates are
monocortically placed at the piriform opening rim,
the zygomatic buttresses, and any regions of the
mandibular cortical bone, Because the anchor
plates work as the onplant and the screws function
as the implant, SAS enables the rigid anchorage
that results from the osseointegration effects in both
the anchor plates and screws.

• SAS does not interfere with tooth movement.
Therefore, it is possible to distalize the mandibular
molars with anchor plates placed at the anterior border
of the mandibular ramus or mandibular body


• Sugawara & Umemori evaluated the treatment and
posttreatment changes during and after distalization of the
mandibular molars, In 15 adult patients, a total of 29
mandibular molars were successfully distalized with SAS.
• The amount of posterior displacement at the crown and root
levels was measured on the occlusograms and the
cephalometric tracings, respectively. The type of tooth
movement was evaluated by the crown and root movement
ratio. When the percentage ratio of the root movement to the
crown movement (the tipping ratio) was less than 25%, the
type of tooth movement was determined to be tipping.


• The average amount of distal move-ment with SAS was 3.5
mm at the crown level and 1.8mm at root apex level. The
maximum amount of distalization at the crown level was 7.1
mm, and the minimum was 1.0 mm at the first molar. The
average tipping ratio was 46.3%. Although most of the first
molars showed bodily movement, 9 of 29 molars showed
tipping movement, in which the tipping ratios were less than
25%.
•

Maximum relapse was 0.8 mm. and the maxi-mum relapse rate
was 40%. The average amount of relapse was 0.3 mm at both
the crown and root apex levels. No significant correlation was
found between the amount of relapse and the tipping ratio and
the amount of tooth movement.

The SAS has outstanding advantages not provided by the
other mechanisms for distalizing the mandibular molars.
• 1. It is possible to intrude the mandibular molars with the
SAS. Therefore the extrusion of the mandibular molars
after the tipping of the molar distalization can be corrected
easily.
• 2. En masse distalization of the mandibular buccal
segments or the entire dentition is also possible if the
mandibular dentition is aligned.
• 3. With the SAS, it is not always neccssary to extract the
mandibular first or second premolars even in patients with
moderate to severe crowding.
• 4. Molar relationship in patients with symmetric or
asymmetric Class III molar relationship can be corrected
without having to extract mandibular premolars.

Conclusion
Traditionally, the arch length deficiency has been
calculated anterior to the first molars because molar
distalization was assumed to be nearly impossible.
However by using the space posterior to the second
molars 14 permanent teeth can be well aligned in the
alveolar bone as demonstrated by these studies.
Therefore it will now become necessary to find an
indicator to determine the posterior limits of the
alveolar region from the standpoints of orthodontics,
anatomy, and periodontology. E.g. Location of
mandibular 3rd molar

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