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Diagnostic Criteria for Maxillary Molar Distalization –
A Review
Anurag Rai*, Shweta Rai**, Mukesh Kumar***
Abstract
In Non-Entraction cases alternatives to extraction are considered for space gain such as proximal stripping,
arch-expansion molar distalization. Uprighting of teeth etcetra. The maxillary molar distalization has made
a great impact in Non-Extraction treatment. Timely distalization of the 1st molars prior to the eruption of
additional molar teeth is an effective method of space gain which is described is this article.
Key Word : Molar distalization, Space gaining methods
INTRODUCTION
P
rofitt 1 discusses several methods of space gain
especially in the teratment of Cl II malocclusion.
These include Differential growth, Extraction and
Orthodontic, Camouflage, Class II intermaxillary elastics
with sliding jigs for distalization etc.
The tooth than can most after cause loss of space is
the 6 year molar. It accomplishes this by drifting mesially
and encroaching the territory needed for the eruption of
second bicuspid. The mesial drift of the 6 year Molar is
only the final act in a series of events that may initiate
space loss.
Headgears are quite successful in maxillary first
molar distalization to gain space in the arch. Except for
its patient compliance.
Hilgers2 introduced the term “Non-Compliance” to
orthodontics, where patient co-operation is minimally
needed. Orthodontists have well encashed this term and
the proof lies in various intraoral maxillary first molar
distalization techniques. Introduced in recent years.
There are many schools of thought related to this
technique though. Many have criticized it as a procedure
of mere transferring the locale of the discrepancy form
front to back.
INDICATIONS
1.
There is mesial tipping or migration of maxillary
first molars. The maxillary first molar often cause
space loss by drifting mesially and encroaching on
the territory needed for the eruption of the second
bicuspid. There are three factors which permit mesial
drift of maxillary first molar.
a. Caries
b. Ectopic eruption of maxillary first molar
*Professor (Orthodontics); **Reader (OMFS); ***Professor, Dr.
B.R. Ambedkar Institue of Dental Science & Hospital, Hari
Om Nagar, New Bailey Road, Patna- 801503
JIDA, Vol. 5, No. 2, February 2011
c.
Iatrogenic mesial drift because of too early
extraction of primary molars by dentist without
placing a space maintainer.
The 21-23 rule3
2.
3.
4.
5.
6.
7.
8.
On the average, 21 mm is required in each lower
quadrant to allow unhindered eruption of permanent
cuspids and bicuspids: Whereas 23 mm is needed
in the upper quadrant. This helps to determine
whether there is adequate space to allow eruption
of the cuspids and bicuspids or there is a need for
molar distalization.
The discrepancy anterior to the first molars does not
exceed 2-3mm on either side and when there is no
evidence of developing posterior crowding.
Incisors are retroclined or when the profile can afford
some proclination.
Patients have normal to near normal mandibular
arch with upright or slight retroclined incisors, no
crowding with flat curve of Spee.
Upper molars placed normally buccopalatally in the
cancellous bone.
An end-on or full class II molar relationship due to
maxillary protrusion.
An end-on or full class II molar relationships due to
maxillary cuspids being either impacted, unrequited
or erupted labially and high in the vestibule.
An end-on full class II molar relationship due to the
ectopic eruption of either the first or second bicuspid.
CONTRA INDICATIONS
1.
2.
3.
Excessive proclination of anterior teeth
Posterior crowding
An end-on or full class II molar relationship due to
retrognathic mandible
4. TMJ problem
5. Unfavourable growth pattern.
James J. Hiligers (1992)4 stated that with maxillary
molar distalization, there is a tendency for anterior bite
279
to open. This open bite generally corrects by itself in
brachyfacial patients but can be a problem in
dolichofacials with tongue thrust habits. He
recommends treating vertical growth patterns
conservatively with extractions, directional headgears
and transpalatal bars.
David J.Snodgrass (1996) 5 suggested that any
expansional and distalization appliance tends to
extrude the molars and therefore molar distalization
should be done with caution in patient with vertical
growth pattern.
John W. Witzing and Terrance J. Spahl (1987) 6
suggested that distalization of the maxillary first molars
aids in increase in vertical height. As the first molar is
distalized, they move closure to the hinge axis of rotation
of the TMJ and came into occlusal contact sooner with
the opposing teeth during the act o closure, thereby
increasing the vertical dimension of occlusion. This is
the reason for contraindication of maxillary molar
distalization in unfavorable growth pattern where lower
anterior facial height is already increased.
TIMING OF DISTALIZATION
Different views have been expressed by different
authors.
Joseph M. Sims (1977)7 suggested that the patient
should be treated before the age of 9 years as the root of
the molar to be moved has not completed its growth and
the orthodontic distal tipping or distal bodily movement
is easier. If the treatment is delayed too long and the
second molar begins to erupt then it requires vastly
increased anchorage and a very efficient appliance
approach in moving first and second molars distally.
Many clinicians suggest that molar distalization is
very efficient, if carried out when the second molar crown
is at the apical third of the molar.
S.R. Langford and M.R. Sims (1981)8 illustrated that
the distal movement of upper molar roots against
adiacent unerupted teeth could cause resorption.
Ottolenguri (1914) suggested that the first molars
should be moved backward against unerupted second
molars during orthodontic treatment with caution as
such movement could result in root resorption of the
first molar.
David J. Snodgrass (1996)5 stated that in the mixed
dentition molar distalization should not be carried out
until full development of the maxillary first molar roots.
In the permanent dentitions, molar distalization is most
effective before the full eruption of the second molar.
James J. Hilgers (1992)4 suggested that the distal
movement of the first molars is most efficient before the
eruption of upper second molars.
But from our clinical experience, we feel that it is better
to do molar distalization as early as possible before
second molar eruption but with caution. Experience has
280
also shown us that distalization of first and second
molars together with recent efficient intraoral methods
is possible without any problem.
UPPER MOLAR POSITION
Cephalometrically, according to Ricketts Analysis,
Upper molar position is the horizontal distance from
Ptyrygoid Vertical Line or PTV Line ( a vertical line
drawn through the distal radiographic outline of
Pterygomaxillary Fissure and perpendicular to the
Frankfort Horizontal) to the distal surface of the
maxillary first permanent molar.
On the average, this measurement should equal the
age of the patient + 3.00 mm (eg. A patient 11 years of age
has a norm of 11 + 3= 14 mm: one mm is added per year
for age adjustment ).
This measurement assists in determining whether the
malocclusion is due to the postion of upper or lower
molar and also is useful in deciding whether extractions
are necessary. It suggests whether sufficient space is
present or not for the second and third molars. This
measurement indicates or contraindicates maxillary
molar distaliztion.
Jedlickova (1990)9 attributed the failure of therapeutic
method of upper first molar distalization by extraoral
traction due to the lack of space. He elaborated a method
Fig. 1 :
JIDA, Vol. 5, No. 2, February 2011
which helped to assess the future spatial possibilities in
the molar region.
MAXILLARY SECOND MOLAR EXTRACTION
IN MAXILLARY FIRST MOLAR
DISTALIZATION
Hilgers (1992)4 suggested that when a great deal of
distal movement is needed and it is preferable not to
extract the upper first bicuspids, it is always beneficial
to remove the upper second molars and let the third
molars drift into place.
Chipman10 believes that maxillary second molar
extraction is indicated when:a. The second molars are severely carious, ectopically
erupted or severely rotated.
b. Mild –to moderate arch length deficiencies exist with
good facial profile.
c. There is crowding in the tuberosity area with a need
to facilitate first molar distal movement.
The optimal time for extracting second molar is when
the third molars have migrated sufficiently in the
maxillary alveolar bone.
Strang and Thompson also recommended the
extraction of maxillary second molars to move first molars
distally with either extraoral appliances or class II
mechanics.
According to Graber11 the indications for second
molar extraction are:
a. There should be excessive inclination of maxillary
incisors with no spacing.
b. Overbite must be minimial or negative
c. Third molars should be present and in a good
position to erupt.
And, the contraindications are:
a. Vertically inclined maxillary incisors
b. No spacing
c. Marked overbite
According to Samir E. Bishara,12 Various advantages
and disadvantages of second molar extraction are as
follows:
Advantages
1. Facilitation of first molar distal movement.
2. Distal movement of the dentition only as needed to
correct the overjet.
3. Reduction in the amount and duration of appliance
therapy.
4. Facilitation of treatment using removable
appliances.
5. Disimpaction of third molars.
6. Faster eruption of third molars.
7. Prevention of “dished in” appearance of the face at
the end of facial growth
JIDA, Vol. 5, No. 2, February 2011
8. Less likelihood of relapse.
9. Good functional occlusion.
Disadvantages
1. Too much tooth substance is removed in class I
malocclusions with mild crowding.
2. Extraction site location far from area of concern in
moderate-to -server anterior crowding
3. Extraction sites of no help in the correction of anterior
posterior discrepancies without patient cooperation
in wearing appliances copable of moving the
dentition to the distal “en mass”
4. Possible impaction of third molars even with second
molar extraction.
SUMMARY
Maxillary molar distalization is supposed to be one
of the pillarstone of the Non-Extraction Theapy. Its
popularity shows its importance. Every other day, a new
maxillary molar distalizer is introduced to the
orthodontic field and most of the Maxillary Molar
Distalizing systems used to-date have been discussed.
With the use recent intraoral methods achieving
approximately 5-6 mm of molar distalization within 4-5
months is a long cherished dream coming true.
Few questions remain and their answer lies in yet to
be developed a unique Maxillary Molar Distalizing
System offering a pure distal translatory movement
without anchorage loss.
The perfect indication of the Maxillary First Molar
Distalization is a Class II molar relationship on a Class
I skeletal base where the second molar are yet to erupt.
BIBLIOGRAPHY
1.
Profit WR. Contemporary orthodontics. Second edition,
Mosby year book 1993: 225-64.
2. Hilgers JJ. The Pendulum Appliance for class II noncompliance therapy. J Clin Orthod 1992; 26(11) : 706-14.
3. Steger ER, Blechman AM. Case reports molar distalization
with static repelling mgnets part II. Am J Orthod Dentofac
Orthop 1995; 108 : 547-55.
4. Hilgers JJ. The Pendulum Appliance for class II noncompliance therapy. J Clin Orthod 1992; 26(11) : 706-14.
5. Scodgrass DJ. A Fixed appliance for maxillary expansion,
molar rotation and molar distalization. J Clin Orthod 1996;
30 : 156-59.
6. Witzing JW, Spahl TJ.The clinical management of basic
maxillofacial orthopedic appliances. Vol-I: PSG Publishing
company. The great second molar debae. 155-216; The
sagittal appliance, 217-278.
7. Sim JM. Minor tooth movement in children. Second edition.
The C.V.Mosby company: 1977: 302-21.
8. Langford SR., Sims MR. Upper molar root resorption because
of distal movement report of a case. Am J Orthod 1981; 79:
669-79.
9. Jeckal N, Rakoshi T. Molar distalization by intra –oral force
application. Eur J Orthod 1991; 13(1) : 43-46.
10. Chipman MB. Second and third molar – Their role in
Orthodontic therapy. Am J Orthod 1961; 47 : 498-520.
11. Grabber TM. Maxillary second molar extraction in Class II
malocclusion. Am J Orthod 1969; 56 : 331-53.
12. Bishara SE., Burkey PS. Second molar extraction – A review.
Am J Orthod 1986; 89: 415-24.
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