Class iii malocclusion

VT’s
CLASS III
MALOCCLUSION
Dr Alvi Fatima
Jr III
Dept. of Pedodontics and Preventive Dentistry

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CONTENTS  Introduction
 Classification
 Frequency
 Etiology
 Variants
 Clinical examination
 Functional examination
 Radiological examination
 Differential diagnosis
 Treatment
 Retention planning
 Conclusions
 References

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INTRODUCTION
• Orthodontic treatment not only involves
establishment of physiologically and
anatomically functional occlusion but also
includes correction of the relationship of the
maxilla and mandible to each other and to
the rest of the craniofacial complex.

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DEFINITION
• According to Angle (1899): Class III malocclusion
occurred when the lower teeth occluded mesial to their
normal relationship by the width of one premolar or
even more in extreme cases. (mesio-occlusion)
• Class III malocclusion can be defined as skeletofacial
deformity characterized by a forward mandibular
position with respect to the cranial base and maxilla.
• The facial dysphasia can be classified into mandibular
prognathism, maxillary retrognathism or combination of
both depending variation of the anteroposterior jaw
relation

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• It is generally agreed by orthodontists that
skeletal Class III malocclusions are difficult to
treat by orthodontic means alone.
• A skeletal class III discrepancy may be the result
of a large mandible, a small maxilla, a distally
positioned maxilla, or any combination of the
three.
• Most often the patients are advised to wait until
the termination of active facial growth so that
maxillofacial surgery can be performed

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CLASSIFICATIONS
 Generally of 2 types:
 Dentoalveolar
 Skeletal
 TWEED (1966)
PSEUDO CLASS III
Normal Mandible
Underdeveloped Maxilla
SKELETAL CLASS III
Large Mandible
Underdeveloped or Normal
Maxilla
CLASS III MALOCCLUSION

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MOYERS
ACCORDING TO THE CAUSE
Osseous
Muscular
Dental

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FREQUENCY OF CLASS III MALOCCLUSION
1) Caucasians 1 to 4 %
7 to 13 Years - 4.2%
14 to 18 Years - 9.4%
2) African – Americans 5 to 8%
3) Asian Maxillary deficiency
Japanese: 4 % younger / 14 % older
Chinese: 3 % younger / 13 % older
Indians: 1.3% (J Ind. Ped & Prev Dent: 1998 – Uteraja et al)
Iranian: 2.1% (East Mediters Health J: 2006: Danaie et al)
Swedish population:

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ETIOLOGY
 McGuigan (1966) – Inheritance of class III
malocclusion in Hapsburg Family, having
the distinct characteristics of prognathic
lower jaw.
 Litton et al (1970) – Dental characteristics
of class III are related to genetic
inheritance.
 Rakosi & Schilli (1981) Functional factors:
Anteriorly positioned tongue believed to be
a local epigenetic factor.
 Also associated with syndromes like Apert
and Cruzons.

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Mental diseases – Compulsive habits of protruding
the mandible.
Enlarged tonsils and naso-respiratory diseases –
Results in anterior tongue posturing.
Premature loss of decidious molars – Results in
anterior mandibular displacement.
Tongue thrusting habit – Prevents eruption of
buccal segments, thus causing auto-rotation of
mandible into excessive intra occlusal space.

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• The posterior ‘squeezing out’ effect of molar
crowding:
– due to crowding in the molar regions, which can contribute
to an anterior open-bite malocclusion in a mandible with
poor vertical growth in the ramus area . Alternatively, good
ramus growth can lead to a Class III malocclusion. This
concept is not well understood, and has not been fully
investigated

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VARIANTS
Ngan P et al: AJODO : 1996
Guyer et al (1986) 13-15 years- 57% - Normal to prognathic
Mand. with Retrusive Max.

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Ellis & Mc Namara 1996: 243 possible types of Class III
Wu, Lin 1986: 75 % of all Chinese Class III have max. retrusion
and increased lower facial heights.
COMPONENTS OF CLASS III MALOCCLUSION
Vertical components :
• Vertical Deficient
• Vertical Normal
• Vertically excess
Anterio-Posterior components :
• Maxillary Deficient
• Mandibular excess
• Combined Maxillary deficient and mandibular
excess

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DENTAL ASSESSMENT FOR DIAGNOSIS OF CLASS
III MALOCCLUSION (molar relation and over jet)
Ngan P et al: Pediat Dent : 1997

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CLASS III SKELETAL GROWTH PATTERN
1) Cranial Base
 Angle – More Acute
 Middle Cranial Fossa  Posterio-Superior Alignment
2) Maxilla
 Decreased horizontal maxillary growth when compared
with the patients with class I malocclusion.
3) Mandible
 Gonial Angle  Obtuse
 Anteriorly placed
4) Dentoalveolar compensation
 Proclination of upper incisors, Retroclination of lower
incisors.

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CLASS III GROWTH PREDICTIONS
• In 1970 Dietrich reported that Class III skeletal discrepancies
change with age.
• These all results indicates that the abnormal skeletal
characteristics can become move pronounced with time.
DENTAL AGE NEGATIVE ANB
ANGLE
MAXILLARY
ANTEROPOSTERIOR
DEFICIENCY
Stage I
Primary
23% 26%
Stage II
Mixed
30% 44%
Stage III
Permanent
34% 37%.

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• Growth prediction can be used to define Class III
tendency and identify specific skeletal morphologic
pattern.
• Certain cephalometric measurements such as cranial
flexure, Porion location and ramus position have been
used predict normal or abnormal growth.
• Mito and Co-workers suggested that accuracy of
prediction is around 70-80% by use of cervical
vertebral to predicted mandibular growth-potential.

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GROWTH TREATMENT RESPONSE VECTOR (GTRV)
ANALYSIS
• GTRV analysis is performed in early permanent
dentition.
• This helps clinicians to decide whether the
malocclusion can be camouflaged by
orthodontic or by surgical intervention once the
growth is completed.
GTRV =Horizontal growth changes of maxilla
Horizontal growth changes of mandible
• GRTV ratio normal individual 0.77 mm at 8-16
year.

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In case of Class III patient have GTRV Ratio 0.33-0.38
mm maxillary deficiency and can be successfully
treated by with camouflage
Class III patient with excessive mandibular growth
with GTRV<0.38 mm then it indicated
Orthognathic surgery.

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GROWTH IN PATIENTS WITH CLASS III
MALOCCLUSIONS
• The craniofacial skeletal pattern of children with Class
III malocclusion is evident in the early deciduous
dentition.
• A sample of 69 Class III subjects were compared with 60
subjects exhibiting normal occlusion.
– They showed both maxillary retrusion and mandibular
protrusion with additional other skeletal characteristics are
short anterior cranial base length, larger mandibular ramus
height and corpus length.

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• Class III skeletal imbalance shows either edge to edge
incisor relationship or an anterior crossbite in deciduous
dentition.
• The skeletal components of the class III malocclusion
tend to worsen along with subsequent growth.
MEAN ANNUAL
GROWTH
INCREMENT
EARLY MIXED
DENTITION
LATE MIXED
DENTITION
MAXILLA 0.8mm / 1.1 mm 1.1 mm / 1.4 mm
MANDIBLE 4.5mm / 2.6 mm 4.4 mm / 2.8 mm
Class III
Normal growers

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INITIAL SYMPTOMS OF CLASS III
MALOCCLUSION
• Early signs of true progressive mandibular
prognathism occasionally can occur in infancy. In
the first months of life a sequential development
of the class III condition may be observed as:
– Eruption of the maxillary central incisors in a lingual
relationship and the mandibular incisors in a forward
position with no overjet.
• Development of an incisal crossbite during the
eruption of the lateral incisors into a normal
relationship.

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• Full incisor cross bites develops
some weeks later.
• Flattening of the tongue as it drops
away from the palatal, contact and
postures forward, pressing against
the lower incisors
• Habitual protraction of the
mandible by the child into the
protruded functional and
morphologic relationship

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CLINICAL EXAMINATION
• The configuration and form of the forehead and nose in relation to
the lower face are significant for esthetic evaluation and prognosis.
• A well formed Naso labial angle is important for esthetic
improvement.
– Acute: the premaxilla segment can be retracted
– Obtuse; the segment must be protracted to improve facial
esthetics.
• The soft tissue of the chin can compensate for or accentuate a
skeletal class III relationship depending on its thickness.
• Gingival recession or dehiscence can often be seen in early class III
malocclusion. This damage is irreversible and is an indication for early
treatment

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The next step is Examination Of The Dentition,
including the morphology and number of teeth.
Congenital absence (e.g., in the maxilla: missing
canine or first premolar teeth) makes treatment
more difficult.
When evaluating the axial inclination of the teeth,
certain disadvantageous irregularities such as labial
tipping of the upper incisors and lingual tipping of
the lower incisors still in anterior cross bite should be
noted. A concavity of the lingual alveolar structure in
the mandible also is a clue to future difficulties in the
correction of Class III malocclusion.

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• Crowding of maxillary teeth also enhances treatment
problems; treatment may require extraction of the
counterpart teeth in the lower arch, leading to great
difficulty in closing spaces and maintaining proper
incisor axial inclination. To make treatment easier if
extractions are required, the clinician should perform
extractions in the mandible before proceeding to those
in the maxilla.
• Depending on the state of development, enucleation or
germectomy may be feasible for the lower first
premolars. The molar occlusal relationship is usually
Class III, but the plane of occlusion also should be
evaluated because its correction may be necessary
before surgery

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FUNCTIONAL ANALYSIS
• The Path Of Closure: from the postural rest position
to occlusion must be carefully studied.
• The mandible may slide anteriorly into a forced
protrusion because of premature contact and tooth
guidance when the jaw closes into full occlusion.
• Such anterior displacements have more favorable
prognosis.
• In contrast, patients with problems caused by an
anterior rest position with respect to habitual
occlusion are difficult to treat and usually require
orthognathic surgery.

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• In addition, a Skeletal Class III with a dental
compensation arising from labial tipping of
the upper incisors on a deficient maxillary
base and lingual tipping of the lower incisors
on an excessively long mandible.
• Orthodontic pre surgical treatment must
decompensate these malpositions before
surgical procedures can be performed.

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TEMPOROMANDIBULAR JOINT AND
TONGUE ASSESMENT
• If the condyle occupies the most posterior position in
the temporal fossa the likelihood of its riding over
the posterior periphery of the articular disk is
increased with concomitant clicking and lateral
crepitus,.
• Abnormal tongue function, size and posture must be
considered. The tongue may be postured low in the
mouth and be flat and elongated, especially in cases
of mouth breathing. In cases of Macroglossia the
tongue is not contained within the dentition and the
scalloping effect of the tooth contact may be visible
on the periphery.

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LIP FUNCTION AND MORPHOLOGICAL
ASSESMENT
• A short hypotonic retrusive upper lip is often seen
in combination with a heavy, redundant, everted
lower lip.
• A closed lip position will produce the appearance
of a long lower lip, as the lip elongates to close over
the class III incisor relationship. The closed lip
length is misleading and should not be used for
treatment planning. Relaxed lip appearance is
deceiving due to hypotonicity of lower lip --- this
causes elevation and apparent lengthening.

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• The lower lip length should be verified with
the lower incisor tip to soft tissue menton
which is not influenced by posture
• Maxillary retrusion is associated with upper
lip retrusion and a straight maxillary sulcus
curve. Upper lip retrusion is treated with
labial crown torque.

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DIAGNOSTIC CHARACTERISTICS OF AN
UNFAVOURABLE CLASS III GROWTH
1. An increased gonial angle
2. Antegonial notching
3. Backward direction of condylar growth
4. Thin mandibular symphysis
5. Compensation in position of upper and lower
incisors in response to disproportionate jaw growth.
6. Mandibular incisors are retroclined as child becomes
older there roots tend to press against the labial
plate producing a WASH BOARD EFFECT. Maxillary
incisors are usually flared anteriorly.

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DIFFERENTIAL DIAGNOSIS OF CLASS III MALOCCLUSION
• Several studies have been done in an attempt to
compare Class III malocclusion with Class I controls
relative to the morphology of the maxilla, the
mandible, and the cranial base. These differences
include the following:
1. The SNA angle is significantly lower in the Class III
samples, indicating a greater degree of maxillary
retrusion.
2. Mandibular protrusion is greater in the Class III
samples.
3. The mean ANB angle in the Class III samples is negative.

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4. The gonial angle is more obtuse in the Class III
samples.
5. The mandibular plane angle is steeper than
normal in the Class III samples.
6. Lower anterior face height is significantly greater
in the Class III samples.
7. The sella angle and articular angle were smaller in
class III samples.
8. Anterior position of the mandible is seen.

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Dentoalveolar Class III:
No apparent sagittal skeletal discrepancy (normal ANB angle)
Tipping of incisors : upper- lingual and lower -labial
Skeletal Class III:
Max retrusion
Mand prognathism
Combination
Negative to 00 ANB angle and Wits appraisal
Increased mand length and more obtuse gonial angle
Tipping of incisors: upper- labial & lower lingual (compensation)
Pseudo Class III (Kwong & Lin 1987)
Ceph values intermediate to class I & III.
Except for functional positioning of Mand in a more protrusive
position probably due to premature contacts (CO-CR discrepancy )
or Habits.
CEPHALOMETRIC CLASSIFICATION

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TREATMENT OF CLASS III
MALOCCLUSIONS
 EARLY TREATMENT IN GROWING CHILDREN
FUNCTIONAL AND ORTHOPEDIC APPLIANCES
 LATE TREATMENT IN LATE ADOLOSENCE AND
NON GROWING ADULTS
ORTHODONTICS + SURGERY
NAGN et al 2001

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THE TIMING OF CLASS III TREATMENT
• Class III malocclusion is established early in life and is not a
self correcting disharmony. Cephalometric and
morphometric gives treatment of Class III malocclusion. It is
carried out more efficiently during early mixed dentition
than late mixed dentition.
• At post pubertal observation (Cs5 and Cs6) when active
growth of the skeleton is completed. Class III subjects
treated with rapid maxillary expander and facial mask well
before the growth (CS1) present and there will be peak
mandibular growth at Cs3 stage.
Early orthodontic treatment: J Daniel Subtenly

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RATIONALE FOR EARLY TREATMENT OF CLASS III
MALOCCLUSION
 To prevent irreversible soft tissue or on bony changes.
Often associated with anterior crossbite leads to
abnormal wear of lower incisor. Dental decomposition
of mandibular incisors leads to tinning of alveolar place
and gingival recession.
 To improve skeletal discrepancies. Early orthopedic
treatment using facemask or chin cup therapy improve
skeletal relations which minimize excessive dental
decompensation i.e. over closure of mandible and
retroclination of mandibular incisor.
• Early treatment eliminate the functional shift, CR-CO
discrepancies and prevents severe Orthognathic
surgeries .
• Early treatment provides pleasing profile thus provides
psychosocial development of a child.
AJODO 2006 Apr Suppl

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• These should be identified at dental age 8 or 9,
soon after the permanent incisors erupt.
• This incisor relationship has the potential to
restrict maxillary development and encourage
mandibular growth, thereby worsening the Class
III problem. (This is similar to the effect of a
functional appliance in Class II treatment.)
• Normally, such displacements can be corrected
by simple tooth movements, and it is important
for treatment to be provided at an early age.
• Subsequently, unrestricted maxillary
development can resume, and if the condyles are
centered in the fossae, this will eliminate the
potential ‘functional appliance’ effect of the
original mandibular displacement.
EARLY CORRECTION OF MANDIBULAR
DISPLACEMENTS

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MAXILLARY RETROGNATHISM
Growing patients who present with maxillary retrognathism should be
considered for early expansion and development of the maxilla.
Use of rapid maxillary expansion and a reverse headgear.
Subsequently, a palatal bar can be used to stabilize the skeletal
change, and then full fixed appliance treatment can be commenced
at approximately 12 years of age.
BORDERLINE SURGICAL CASES
In some cases with mandibular excess, the diagnosis will suggest that
mandibular surgery may be needed. It is helpful to delay
orthodontic treatment for such cases, if possible. This will allow
assessment of growth patterns, using regular cephalometric
radiographs, so that a more informed surgical/non-surgical decision
can be reached.

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CLASS III SURGICAL CASES
• Some cases are clearly Class III surgical cases
from the outset, and SHOULD NOT BE
TREATED UNTIL ALL GROWTH HAS CEASED.
• Timing will be beyond the age of 20 years in
males and a little earlier in females.

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Rickets (AJO 2000) has summarized the main
objectives of early treatment lying in five
concepts
1. Obtaining a skeletal change (structural)
2. Providing the opportunity of a functional change
in the environment
3. Utilization of the individual growth towards the
correction.
4. Elimination of the detrimental habits (breathing
etc)
5. Taking advantage of the forces of the occlusal
development towards the correction.
AJODO 2000

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Turpin has developed a list of positive and negative factors
to aid in deciding when to interrupt a developing class
III malocclusion
POSITIVE FACTORS
1. Good facial esthetics
2. Mild skeletal disharmony
3. No familial prognathism
4. Antero posterior functional shift
5. Convergent facial type
6. Symmetric condylar growth
7. Growing patients with expected good cooperation.
8. If the above factors are not present in the patient ,
they are listed as negative and treatment can be
delayed until growth is completed.

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Joondeph, after Turpin’s thesis, also pointed out
the goals of early intervention:
1. Reduce the skeletal discrepancy and provide a
more favorable environment for normal growth.
2. Achieve as much relative maxillary advancement
as possible.
3. Improve occlusal relationships.
4. Improve facial esthetics for more psychosocial
development.
5. Reduce or simplify, phase II or surgical treatment.

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PERMANENT DENTITION THERAPY
Extraction therapy may have limited applicability in
Class III treatment.
For example, we would not want to limit
extractions to the lower arch because many
times the incisors are generally inclined lingually
and extraction treatment tends to increase this
inclination, possibly beyond the limits of the
lingual plate of bone. Also, extractions may be
contraindicated when orthodontic treatment
must be combined with surgical treatment.

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• Another consideration is that many of the forces in
conventional orthodontics carry risks because of the
unfavorable growth pattern in patients with Class III
malocclusions.
– For example, many patients with Class III malocclusions have an
increased vertical face height, particularly of the lower anterior
part of the face, with an open-bite.
– In these patients, Class III elastics and second-order bends in the
posterior regions cannot be used conveniently because the
extrusive force components on posterior teeth can open the bite
and increase the vertical dimension further. Particular attention
must be paid to the use of Class III elastics because they can also
extrude the mandibular incisors, and there is frequently
excessive vertical dentoalveolar development in the incisor
region.
• Since many of the conventional treatment procedures
have limitations, we should consider the use of extra oral
traction because appropriate force systems can be placed
with fewer deleterious side effects.

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There are three important diagnostic principles
which merits attention.
• First Principle:
– it is particularly important to determine whether the
mandible, on closure, is in centric relation or in a
"convenient" anterior position.
– The practical implication is that a Class I problem can
appear to be a Class III malocclusion (Pseudo-Class III
malocclusion) when the mandible is forced anteriorly
.
– Even a true Class III malocclusion can appear much
more serious if there is an anterior path of closure of
the mandible

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Type
Anterior
position of
mandible
Centric relation and centric
occlusion Significance
Pseudo-Class III Present Not coincident
Problem is less
difficult than it
appears ( in a Class I)
actually.
True Class III Present Not coincident
Not coincident
Problem is less
difficult than it appears
True Class III Absent Coincident
Problem is as difficult
as it appears

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• Second Principle:
– is that the nature of the skeletal discrepancy must
be defined because treatment, to a large extent, is
based on this differential diagnosis.
• Class III malocclusions can be classified as
An under developed maxilla---TYPE A
An over developed mandible--TYPE B
A combination of TYPE A and TYPE B

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• Third Principle:
– a malocclusion reflects the interplay of many
conditions that may be impossible to evaluate
singularly. One important variable is the potential
growth and development of a patient with a Class III
malocclusion. In this context, at least two factors may
be detrimental and aggravate Class III malocclusions
with time. One is the differential growth of the jaws,
carrying the mandible more anteriorly relative to the
maxilla. Also, local conditions (such as low tongue
posture) may adversely influence the growth pattern.
Since the amount and the timing of growth of the
mandible cannot be assessed accurately, we cannot
consider a Class III malocclusion fully resolved until
facial growth has ended.

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TREATMENT FOR TYPE A CLASS III
• Characteristic of this type in which the maxilla appears
retrognathic is a concave profile which represents
underdevelopment of the middle part of the face,
rather than prominence of the mandible. Treatment
should be started early, (as early as 4 years of age) for
two fundamental reasons.
1. Extraoral traction which pulls the maxilla anteriorly
functions in the same direction as the direction of
development.
2. Unlike posterior movement of the mandibular arch,
anterior movement of the maxillary arch appears to
have a greater chance of remaining stable.

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• RESULTS ACHIEVED:
– An orthopedic protraction of the maxilla with a
strong force (500 to 1,000 Gm per side). This
change appears to be limited especially if
treatment is started after 6 years of age,
– An increase in the inclination of the maxillary
incisors to obtain a sufficient overjet,
associated more or less with Bodily movement
of all the teeth in an anterior direction,
advancing point A.
– RESULT: Both an improvement in function and
a more esthetic profile.

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FACE MASK
• The use of Protraction Headgear - > 100 years ago
• Early orthopedic intervention - non surgical alternative
in the treatment of Class III malocclusion with maxillary
retrusion.
• Protraction headgear – FORCE -directed forwards in the
same direction of growth of the maxilla
• An EXTRA ORAL FORCE of 300 gm or more per side,
when applied, can cause significant changes in the
circum maxillary sutures and in the maxillary tuberosity.
• Tension produced within the sutures was believed to
cause an increase in vascularity and a concomitant
differentiation of the cellular tissues resulting in
increased osteoblastic activity.

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RESULTS PRODUCED :
In an animal study with tantalum implants and oxytetracycline dyes,
heavy intermittent maxillary protraction was found to produce
forward displacement of the mid face, anterior relocation of the
inferior border of the orbit, and gross osseous alterations
extending superiorly to the area of the fronto maxillary suture.
The study also found that post treatment skeletal rebound was
minimal and was observed only during the first month after
discontinuation of mechanical forces.
Clinically, the maxilla can be advanced 2 to 4 mm over a 12 to 15-
month period of headgear treatment. The use of protraction
headgear has been shown to be most effective in the full
deciduous or early transitional dentition, with less skeletal
changes after 9 years of age.
But, a recent longitudinal study suggested that orthopedic effects of
protraction headgear on dentofacial structure was possible in
young girls as late as during the acceleration phase of pubertal
growth spurt.

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APPLIANCE DESIGN:
• The orthopedic facial mask consists of three basic
components.
– FACIAL MASK
– BONDED/ BANDED MAXILLARY SPLINT
– ELASTICS
• The facial mask : an extra oral device composed of
– a fore head pad
– a chin pad that are connected with
– a heavy steel support rod.
– To this support rod is connected a cross bow to which are
attached rubber bands to produce a forward and
downward elastic traction of the maxilla.
– The position of the pads and the cross bow can be
adjusted simply by loosening and tightening set screws
within each part of the appliance.

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PARTS OF PETIT FACE MASK
The major modification in the appliance is the addition of facial mask
hooks in the upper first deciduous molar. In patients in whom treatment
is started before the eruption of the upper first molars, the appliance is
designed to incorporate the first and second deciduous molars as well as
deciduous canines

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Petit face mask lateral and frontal view

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DELAIRE FACE MASK TUBINGER FACE MASK

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• The splint is activated once per day until the
desired increase in transverse width has been
achieved. In patient in whom no increase in
transverse dimension is desired, the appliance
still activated for 8-10 days to disrupt the
maxillary sutural system and to promote
maxillary protraction (HASS 1965)
• After the patient has been accustomed to
wearing the maxillary splint, the facial mask
treatment is initiated. The current version of the
petit facial mask is one universal size and can be
adjusted to fit the facial contours of most
patients.

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SEQUENCE OF ELASTICS:
• At the time of delivery 3/8” 8 oz 2 weeks
• After 2 weeks 1/2” 14 oz
• Increased to a max. of 5/16” 14 oz
• Timing of wear:
– Young patients (4 - 9 years) should wear the mask on a
full time basis except during meals.
– In older patients, it is worn at all times except during
school
• Duration is 4-6 months.
• Retained: with only night time wear or with a
maintenance plate, chin cup, FR III or a modified
utility arch with Class III elastics.

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SKELETAL EFFECTS OF MAXILLARY PROTRACTION (
sutures involved):
• The maxilla articulates with nine other bones of the
craniofacial complex: frontal, nasal, lacrimal, ethmoid,
palatine, vomer, zygoma, inferior nasal concha, opposite
maxilla, and occasionally sphenoid.
• Palatal expansion had been shown to produce a forward
and downward movement of the maxilla by affecting
the intermaxillary and circummaxillary sutures.
• The disruption of these sutures may help initiating
cellular response in the sutures, allowing a more
positive reaction to protraction forces.

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Sutures involved in face mask

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Kambara found changes at the circummaxillary
sutures and at the maxillary tuberosity
attributable to posteroanterior traction, including
the opening of sutures, stretching of sutural
connective-tissue fibers, new bone deposition
along the stretched fibers, and apparent tissue
homeostasis that maintained the sutural width.
Nanda and Hickory showed how the histologic
modifications in the zygomatico maxillary suture
after maxillary protraction varied according to the
orientation of the force system applied.

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BIOMECHANICS:
The centre of resistance of the maxilla is located at the
distal contacts of the maxillary first molars, one half the
distance from the functional occlusal plane to the
inferior border of the orbit.( Lee AJO 1997)
Protraction of maxilla below the Centre of resistance
produces counter clock wise rotation of the maxilla.
Also Hata et al (AJO 1987) found using human skulls
that protraction forces at the level of the maxillary arch
produces forward but counter clock wise rotation
unless a heavy downward vector of force was applied.

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• A heavy force at 300 -450 gms on either side at about
300 to the functional occlusal plane in both primary
and mixed dentition is recommended by most
authors producing 10 degree of counter clock wise
rotation being acceptable .
• Direction of force: Downwards and forwards
• Point of Application: 5 mm above the palatal plane in
the canine region.
• Hata et al suggested that an effective forward
displacement of the maxilla can be obtained with this
point of application

VT’s
EFFECTS OF THE FACE MASK
1. The maxillary incisors moved in the anterior direction,
whereas the mandibular incisors moved posteriorly.
2. After maxillary protraction, the maxilla was displaced
anteriorly, whereas the mandible rotated posteriorly.
3. The mandibular plane angle and anterior lower and
total face heights increased.
4. There is no change in SN-palatal plane angle during
growth period.
5. These changes were reflected in the profile, whereby
the skeletal profile convexity increased and soft tissue
facial angle and facial convexity increased; and the
Class III concave profile became more balanced, with
the upper lip area becoming more marked.

VT’s
6. Position of the posterior nasal spine remained stable
7. Over bite was improved by eruption of maxillary and
mandibular molars.
8. Anchorage loss was observed during maxillary
protraction with mesial movement of the maxillary
molars. An average of 5.68 mm anterior movement of
the upper incisors resulted in a significant amount of
upper lip protraction.
9. The ratio of upper lip protraction to upper incisor
protraction relative to the vertical reference line was
1:1.26
10. A significant decrease in upper lip thickness to
vermilion was caused by the fact that during the
treatment period, total anterior movement of the
upper incisors was approximately 1 mm more than
that of the upper lip.

VT’s
11. A significant decrease in the upper lip sulcus depth can be
evaluated as another favorable effect of the appliance on
the soft tissue profile.
12. The lower lip moved posteriorly to lie behind the Steiner S
line
13. After the correction of the crossbite in Class III cases, the
lower lip most often contacts both lower and upper
incisors and would therefore be influenced not only by the
retraction of the lower incisors but by protraction of the
upper incisors as well.
14. Backward repositioning of the pog’, and slight inhibition of
anterior migration of the lower lip was seen.
15. Upward and Forward Rotation of the maxilla occurs when
protraction force on molars is applied parallel to the
occlusal plane. This type of maxillary rotation can be
minimized when the force is applied in the canine area, 20°
to 30° below the occlusal plane.

VT’s
Movement of A point in different studies

VT’s
Rapid maxillary expansion is the corner stone of
increasing the transverse dimension in growing
individual.
In general there are three types of expansions are
there to increase the transverse dimension
1.ORTHODONTIC EXPANSION
2.PASSIVE EXPANSION
3.ORTHOPEDIC EXPANSION

VT’s
RAPID MAXILLARY EXPANSION
# Indications for RME
• Patients who have LATERAL DISCREPANCIES resulting in
either unilateral or bilateral posterior crossbites
• ANTERO-POSTERIOR DISCREPANCIES
• Cleft lip and palate patients with collapsed maxillae .
• Procedure to gain arch length in patients who have
moderate maxillary crowding.

VT’s
# Contraindications for RME
• Non cooperate patients
• Patients who have a single tooth in crossbite
• Patients who have anterior open bites, steep
mandibular planes, and convex profiles
• Patients who have gross skeletal asymmetry of
the maxilla or mandible
• Adults with severe anteroposterior and vertical
skeletal discrepancies

VT’s
Face mask protraction therapy in early
skeletal Class III
• Does RME enhance the efficiency of maxillary
protraction with face mask in developing Class III
malocclusion?
• Results: Face mask therapy effective in early Class III
MO
• The need for palatal expansion in the absence of a
transverse discrepancy or a skeletal/ dental cross bite
is not supported.
• Correction due to combined skeletal and dental
change.
AJO DO 2005 128; 299-309

VT’s
Critical appraisal
• The skeletal change following protraction is
significant.
• But has no correlation with expansion.
Kalha A S: EBD 2006:7,16-17

VT’s
MODIFIED PROTRACTION HEAD GEAR
A modified protraction headgear design and the
biomechanical considerations of its clinical use are
presented by Nanda (1980 AJO).
The clinical results show that a modified protraction
headgear with a chin cup helps in the correction of
moderately severe Class III malocclusions by the
anterior displacement of the maxilla and maxillary
dentition, and possibly restricting or changing the
direction of the growth of the mandible.
This headgear can also be used to correct axial inclinations
and or mesial displacement of posterior teeth

VT’s
This functions to produce anterior
movement to the maxilla and to
redirect the anterior movement of the
mandible.
 This appliance can be used when
strong forces are not necessary.
 Under these conditions, however,
the orthopedic effect may be limited.

VT’s
Use of removable appliances in Class III
malocclusion
Use of removable appliances which are placed in
the deciduous dentition stage of development or
in the mixed-dentition stage when certain teeth
have exfoliated or are carious.
If retention of the removable appliance is adequate,
we can apply up to 500 Gm. per side.
Some of the mild class III can be treated with bite
planes in the anterior region (Nanda 2006)

VT’s
TREATMENT FOR TYPE B CLASS III
Characteristic of this type of malocclusion is the
overdevelopment of the mandible, especially
in relation to the maxilla.
The treatment of choice would be to inhibit or
redirect the growth of the mandible. For this
purpose, a few appliances are available.

VT’s
CHIN CUP
Orthopedic force with the chincup or mental
anchorage - serves to redirect mandibular
growth
Appliances resembling chin cups have been in
use since the early 1800's.
Thilander treated sixty patients with chin cups
for 1 to 6 years. A significant percentage of
patients did not improve. The patients who
showed improvement were comparatively
young and showed favorable dental changes.
The force generated by the chin cup in his

VT’s
OCCIPITAL PULL CHIN CUP VERTICAL PULL CHIN CUP
Types of chincup

VT’s
According to Graber, the early attempts with the chin cup
were not successful because of incomplete knowledge of
mandibular and facial growth, its use on non growing
patients, and an inadequate understanding of the forces
generated by the chin cup.
Armstrong applied 500 Gm. of force via chin cups on 100
adolescent patients with mandibular prognathism. He
reported that half of his patients showed improvement in
the Class III profile, whereas none of the control / non
treated patients showed any favorable change.

VT’s
Graber, Chung, and Aoba reported results in patients
treated with chin cups for 12 to 14 hours each day with a
force of 1.5 to 2 pounds on each side. They showed that
mandibular growth could be redirected with a chin cup.
They asserted that continuous use of the appliance for a
long period or through active growth was necessary to
achieve stable results.
Graber treated 35 Class III malocclusions in children
between the ages of 5 and 8 years with chin cup therapy
for 3 years. He found that the therapy was particularly
effective in patients with increased vertical growth of
the face.

VT’s
• Chin cup therapy primarily works on the hypothesis
that “A force directed through the condyles will inhibit
as well as redirect the condylar growth.”
• However, this therapy alone may not be indicated for a
fair percentage of patients in skeletal Class III who show
a small midfacial bone or a retropositioned maxilla with
relatively normal mandibular dimensions.
• Jacobson et al studied 149 Class III patients and noted
that in approximately one fourth of the sample the
problem was due to maxillary deficiency.
• Several clinical studies in the past have noted that
treatment of patients in skeletal Class III should include
protraction of the maxilla with or without chin cups.

VT’s
As the neck of the condyle reverts back toward its former position
post treatment, as it usually does (De Vincenzo 1991), one of four
post treatment reactions must occur;
1. The molar relation must revert back toward Class III occlusion,
2. The lower molars must move forward on the mandible,
3. There must be a change in the temporal mandibular joint, or
4. There must be a dual bite.
The authors of the Class III study speak of “shrinkage” of the
condylion- pogonion distance, but this is a misnomer. The distance
does not become smaller, it only fails to increase in proportion to
the growth of the condyle, because of the reduction of the gonion
angle. The backward bending of the neck of the condyle followed
by a reversion to its former position must be related in some
unknown way to maintaining the constancy of the axis of the
ramus.

VT’s
TREATMENT OF TYPE A AND TYPE B
This generally requires a combination type of therapy to produce
anterior movement of the maxilla and posterior movement of
the mandible. This is chosen when the malocclusion reflects
underdevelopment of the maxilla associated with hyper
development of the mandible. It can also be done when, during
treatment, to accept a compromise result between relationships
of the mandible and maxilla.
Maxillary protraction and mandibular retraction can be achieved by
using, in successive treatment periods, two types of extraoral
traction. For example, initially, a facial mask may be used to gain
space for the maxillary teeth and to protract the maxillary arch.
In a subsequent treatment period, an extraoral appliance can be
used to move the mandibular arch distally or, at least, to control
the incisor region and possibly influence mandibular growth and
development

VT’s
CLASS III ACTIVATOR
The activator was introduced by Andresen and has been long
served for correction of skeletal Class II malocclusions.
Rakosi suggested modification of the activator for use in Class III
treatment. The appliance consists of wire and acrylic parts.
The wire components are
• 4 stop-loops located mesial to all first molars to prevent mesial
tipping of the molars and to stabilize the appliance,
• lower labial bow to stabilize the appliance,
• upper labial pads to remove the force of the upper lip and
create periosteal pull to induce bone formation, and
• Tongue Crib to correct anterior tongue thrusting habit.
Somchai Satravaha: AJODO 1999

VT’s
 The construction bite is taken by retruding the lower jaw.

VT’s
Post treatment Changes
• ANB angle as well as the Wits value remained quite stable.
• The SNA, SNB, SN-Pog, and NA-Pog became larger.
• The articular angle was increased
• The gonial angle exhibited a compensatory decline resulting in
decreasing of the sum angle
Long-term Results
• The Class III activator produced a more posterior position of the
mandible and changed direction of the mandibular growth.
• Both alterations remained through the post activator period.
• The maxilla and the mandible grew with an increase in maxillo
mandibular differential; the maxilla remained in a more forward
position
• There was significant difference in the degree of change of angle
OP/Go-Gn during the treatment but disappeared in the post
activator period due to compensatory reduction of the gonial
angle.

VT’s
ACTIVATOR MODIFICATIONS
KARWATZKY’S MODIFICATION
WUNDERER’S MODIFICATION

VT’s
TWO PIECE CORRECTOR
The Two-Piece Corrector was designed by Gerald R.
Eganhouse to apply biological forces that will
counteract any Class III developmental vectors, whether
skeletal or dentoalveolar, and correct or minimize their
effects on the patient .
It is a removable acrylic appliance that simultaneously
applies an anterior force to the maxilla and an equal
posterior force to the mandible.
The flat, sliding surfaces of the two pieces create almost no
friction as the dentition is disoccluded during
movement, but provide both lateral and anteroposterior
stability JCO 1997

VT’s
Appliance construction:
• A construction bite of 4-6 mm thick is taken using an “Exacto Bite”
registration jig. This gives an accurate centric relation, since the
mandibular incisors can be positioned precisely.
• In the laboratory, a slide is created on the articulator, with the male
(guide) portion in the maxillary acrylic plate and the female
(groove) potion in the mandibular plate. The male portion is
extended about 15 mm distal to allow for anteroposterior sliding
and to ensure lateral stability as correction progresses. The anterior
portion of the two pieces will flush when the appliance is inserted,
but the maxillary piece will gradually slide forward on the
mandibular piece
• Elastics provide the force between two parts of the appliance – one
hook on each side of the maxillary plate on the disto buccal aspect
of the maxillary first molar, two located in the maxillary first
bicuspid – canine area, and the fourth placed between the
mandibular canine and lateral incisor

VT’s
Two piece corrector
MALE GUIDE
FEMALE GROVE

VT’s
The shorter elastics (1/8 ” 6oz ) are attached from the
mandibular hook to the most anterior hook on the
maxilla.
As treatment progresses, it is moved to the posterior
hook. The longer elastic on each side stretched from the
mandibular hook to the molar hook can be (¼”, or 3/16”
– 6oz) depending on the comfort.
DURATION:
12 hours a day in conjugation with face mask. 11 months
of treatment time and 18 -24 months of retention
INDICATION:
Mild skeletal class III where future surgery would not be
indicated. And used during preadolescent and
adolescent growth periods

VT’s
CLASS III BIONATOR
BALTERS BIONATOR III can be
used in patients with skeletal
Class III malocclusion. The use
of this appliance causes some
skeletal changes through
neuromuscular modifications.
Garatinni et al AJODO 1998

VT’s
FRANKEL III APPLIANCE
• Upper lip pads
• Lower labial bow
• Protrusion bow in the upper arch

VT’s
REVERSE TWIN BLOCK
MODE OFACTION
MODIFICATIONS
• WITH UPPER LIP PADS
• WITH REPELLING MAGNETS

VT’s
MAGNETIC APPLIANCE
AO 2005

VT’s
Functional Orthopedic Magnetic Appliance (FOMA III)
AJODO 1990

VT’s
MAXILLARY EXPANDER WITH MINI MAXILLARY
PROTRACTOR
JCO 2005 & AO 2006

VT’s
TOOTH BORNE ORTHOPEDIC MAXILLARY
PROTRACTOR
Liou et al JCO 2005

VT’s
MODIFIED TANDEM APPLIANCE
JCO 2003

VT’s
FIXED SAGITAL APPLIANCE
Fun Ortho 2004

VT’s
CERVICAL MANDIBULAR HEADGEAR
WJO 2006

VT’s
TREATMENT OF CLASS III
MALOCCLUSIONS IN ADULT OR
NONGROWING INDIVIDUALS

VT’s
The selection of treatment strategies
• When a patient is diagnosed as a Class III
malocclusion in the permanent dentition and if
there is a strong skeletal component to the
Class III malocclusion then treatment options
are less.
• Such treatment usually includes
comprehensive orthodontic therapy, either
combined with extraction or orthognathic
surgery.

VT’s
• The Orthognathic surgical procedure is designed to address
the imbalance of the skeletal component (Eg: mandibular
set back in patient with mandibular prognathism and Le-
Fort I advancement in maxillary skeletal retrusion.)
• In patients who are expected to have excessive skeletal
growth in the future, the surgical procedure is usually
deferred until the end of active growth period.
• In the diagnosis and treatment planning of patients who
present with a Class III malocclusion in the late deciduous or
in the mixed dentition, several treatment options are
available.

VT’s
CLASS III MECHANICS
• Inter-maxillary Class III elastics are
most helpful in orthodontic (non-
surgical) correction of Class III
cases.
• They tend to produce lower incisor
retroclination, upper incisor
proclination, and A/P correction of
the molar relationship.
• All components of the Class III
elastic force can therefore be
helpful in reaching treatment
goals in average or low angle

VT’s
• Lower first premolar extractions are most
favorable in assisting lower incisor distal
movement, or Extraction of lower 2nd molars
and Distalization of the 1st molar to achieve a
class I molar relation (AO 2006) .
• If the lower arch is managed on a non-
extraction basis, Class III mechanics can be
used to produce some retraction and
retroclination of the lower incisors. This can
produce distal tipping of the lower premolars
and molars, which in turn reduces the
available space for the lower third molars .

VT’s
• Early removal of lower 3rd molars can be
considered in some cases.
• A non-extraction approach to Class III treatment
may not achieve sufficient lower incisor
movement for the needs of the case.
• Correction of the malocclusion may be possible,
but not over-correction. Thus, there is no
provision in the result for any late growth
changes, which occur relatively frequently in Class
III cases, especially among male patients.

VT’s
SURGICAL / NON-SURGICAL DECISION IN CLASS III
TREATMENT – based on STCA of Arnett et al 1993 &
1999
As with Class III treatment, it is important to
recognize those Class III cases which have a
major skeletal disproportion, either at the time
of assessment, or where there is a probability of
unfavorable growth. For such individuals, it will
be necessary to consider a surgical / orthodontic
solution.

VT’s
• Treatment on the basis of orthodontics alone
should be delayed, or discarded as :
– This will involve proclination of upper incisors
and retroclination of lower incisors.
– Good patient cooperation with Class III elastics
and/or a face mask will normally be needed in
this type of treatment.
– This should lead to an acceptable dental and
facial outcome without the need for orthognathic
surgery.

VT’s
SURGICAL ORTHODONTICS
The incisors will need to be decompensated by
orthodontics before surgery, if there is to be an
optimal facial benefit from the surgery: REVERSE
ORTHODONTICS
The treatment of Class III malocclusions is
relatively easy when the problem is confined to
the alveolar bone, but when the deformity is in
the basal bone such as in a deficient maxilla or
overgrowth of the mandible, and then the
malocclusion does not respond readily to
treatment and tends to recur after treatment.

VT’s
SITUATION A – A SURGICAL/ ORTHODONTIC CORRECTION TO AN
IDEAL RESULT
Determined that mandibular surgery will be required, then the
surgeon will normally wait until all growth has finished, which may
be as late as 22 years of age in males. The surgeon will then
require the orthodontist to decompensate the incisors. Correction
will be achieved by A/P realignment of the mandible and/or
maxilla, with transverse correction of the maxilla if necessary. This
should lead to an optimal facial and dental result.
A 6-mm mandibular set-back will
result in measurements to true
vertical line (TVL) which are
within 1 SD of the ideal.

VT’s
SITUATION B – ORTHODONTIC MASKING OF A MILD CLASS III
SKELETAL CASE.
As an alternative to ‘A’ above, if the underlying skeletal discrepancy
is mild, it may be decided to follow a treatment plan based on
orthodontics alone. This will allow correction to be commenced
much earlier, and the patient will be informed of the possibility
of late mandibular growth. The orthodontist will then solve the
problem by ‘masking’ the underlying Class III discrepancy by
dental compensation- CAMOFLAGUE
In this theoretical representation, the
upper incisors were proclined 2° and
the lowers were retroclined 8°.

VT’s
SITUATION C – LATE MANDIBULAR GROWTH:
After orthodontic masking of a mild Class III malocclusion, late
mandibular growth can occur, especially in males. This is a
difficult situation to manage! Sometimes the patient will find the
late change in dental and facial outcome acceptable, and seek no
further treatment. However, if mandibular surgery is deemed
necessary, there is limited scope for facial improvement from the
surgery, because of the dentally compensated teeth.
In some cases, late mandibular growth
occurs after the type of treatment
shown in ‘B’ above. This is difficult to
manage.

VT’s
Combined Orthodontics and Orthognathic Surgery
• Early surgery is possible in maxillary deficient but
surgical intervention in young child may further
adversely affect the growth of maxilla.
• Patients with true mandibular prognathism may
continue to grow for several years beyond the
puberty so that two lateral cephalograms are
taken at least 1 year apart demonstrate no
significant growth occurring over that period.

VT’s
• The current surgical methods for correcting
skeletal Class III problems include:
–Setting back prognathic mandible.
–Mandibular inferior border osteotomy to
reduce chin height or prominence.
–LeFort I osteotomy to advance a deficient
maxilla.

VT’s
Treatment to camouflage the Class III skeletal
discrepancy.
• Skeletal discrepancies can not be resolved during
mixed dentition by growth modification may require
comprehensive appliance therapy or surgical
correction.
• Some patients treated in early childhood may recur
malocclusion during adolescence. Treatment in
adolescence is indicated to alleviate the potential
psychosocial problems and reduce the need for
surgery.
• Malocclusion with mild mandibular prognathism and

VT’s
• Class III elastics with or without extraction of teeth
are used to camouflaged the skeletal discrepancy,
resulting in acceptable facial profile.
• As early as 1907 Edward Angle suggested that the
only way to correct severe Class III malocclusion in
adult was to combine surgery and orthodontic
treatment.
• Before 1970s must thought that Class III malocclusion
were primarily caused by excessive anteroposterior
growth of the mandible and most were corrected by
mandibular setbacks procedures.

VT’s
• However later studies indicated 20-25% of
mandibular protrusion, but also around 75% of
maxilla deficient cases also leads to Class III
malocclusion so that clinician should analyse where
the fault, whether in maxilla or mandible or
combination.
• Maxillary growth may be completed at age 14 - 15
years were as mandibular growth may continue until
early 20 years. After this surgical procedure can be
carried out.

VT’s
C ORTHODONTIC MICROIMPLANT FOR DISTALIZATION
OF MANDIBULAR DENTATION IN CLASS III
MALOCCLUSION
Chung, Kim, et al : AO 2006

VT’s
PRE SURGICAL ORTHODONTICS IN MANDIBULAR
PROGNATHISM
• Eliminate anterior and posterior dental
compensation with guideline from orthodontic
visual treatment objectives (VTO).
• Establish appropriate anteroposterior and vertical
incisor position.
• Achieve compatible arch forms and inter canine
widths, which are essential to make dental midlines
compatible at surgery.
• Correct tooth size discrepancy

VT’s
• Class III mechanics, molar tie backs are not used
when leveling & teeth are allowed to level
forward. The orthodontic VTO should be referred
to confirm the extent of incisor decompensation
required.
• On the completion of leveling, Class II elastics
may be used to advance the mandibular buccal
segment and further to procline the mandibular
incisors.
• When decompensating the mandibular incisors,
clinician should keep in mind, patient with
mandibular antero posterior excess often have a
very thin bony symphysis and a small area of
attached gingiva in the incisor region

VT’s
SURGICAL TREATMENT
• Bilateral sagittal split osteotomy (BSSO) is the
procedure of choice,
• Although (TOVRO) trans-oral vertical ramus
osteotomy may be indicated in large setback
procedures.
NOTE: Correct positioning of condyle is important. The
surgeon should carefully free the medial pterygoid
an a stylomandibular ligament from the medial side
of the ramus. Otherwise proximal segment will be
pushed back by distal segment & with return of
muscle function, the patient will tend to position
mandible forward again.

VT’s
• The incidence of neuro-sensory morbidity with
trans-oral Vertical ramus osteotomy is less
associated with bilateral sagittal split ramus
osteotomy.
• A genioplasty is often indicated to place the
chin in most esthetic antero posterior, vertical and
midsagittal position.

VT’s
POST SURGICAL ORTHODONTIC
• The clinician should design the retention plan
according to original malocclusion and its possible
relapse tendency.
• If tendency to relapse is noticed, light (2.5 - 3.5 oz)
Class III elastics should be placed immediately.
• A rectangular arch wire should be placed in maxilla
to prevent the molar extrusion.

VT’s
Costa et al 2001 reviewed post operative stability in
mandibular set back and concluded that:
• BSSO for Class III – 30% likelihood to relapse
• For isolated mand set back (1.49mm = 22.6%) the
most important factor responsible for relapse is its
magnitude.
• In bimax surgeries (set back = 5.44 mm & relapse =
3.33 mm – 61.2 %) : counterclockwise rotation of
the proximal segment
• Rigid internal fixation did not guarantee more
stability.(9.8 – 66%)
Int’l J of adult ortho & orthga surgery: 2001

VT’s
MAXILLARY ANTEROPOSTERIOR DEFICIENCY
• Maxillary anteroposterior deficiency often
misdiagnosed as mandibular
anteroposterior excess. So the clinician must
carefully distinguish between the two
deformities.

VT’s
• Cases of maxillary deficiency often involve crowding
in the maxilla and retraction of incisor is indicated.
This will require extractions.
1.If maximum retraction is necessary or significant
crowding is present - extn of 1st premolar is
indicated
2.If little retraction is necessary or crowding is slight –
2nd premolar is indicated.
3. Advancement of mandibular incisors from an upright
or lingually tipped position may be limited by lack of
attached gingiva or thin alveolar bone and
symphysis. Extn of mandibular 2nd premolar is
necessary to provide required space to manage
crowding.

VT’s
Orthodontic Mechanics:
Pre surgically:- the maxillary incisors should be
placed in good angulation in the central
trough of bone. To achieve best esthetic
results.
Surgical treatment:-The maxilla is advanced by
means of Le-fort I Osteotomy. So surgeon
can correct discrepancies in the Vertical,
Transverse and Sagittal planes.

VT’s
• Undesirable soft tissue changes may occur,
including widening of &/or tipping up of the nose
and increased nasolabial angle. So that patient
should be informed about expected soft tissue
changes.
Post surgical orthodontics:-
• Surgical splint is given only in multipiece LeFort-I
maxillary osteotomy or in bi-jaw surgery.
• Once the splint is removed immediately the
orthodontist should place orthodontic palatal bar
and continuous arch wire to maintain achieved
results.

VT’s
• In as study done by Chen et al in 2007 compared
the short and long term effects of bimaxillary
surgery and mandibular setback on the narrowing
of airway and concluded that bimaxillary surgery
prevent narrowing of the airway space, which
may lead to obstructive sleep apnea.
AJODO 2007

VT’s
CURRENT TRENDS AND FUTURE PROSPECTS
• DISTRACTION OSTEOGENESIS:

VT’s
PHASES AND TIME TABLE OF DISTRACTION

VT’s
DENTAL ONPLANTS FOR ABSOLUTE ANCHORAGE IN MAXILLARY
PROTRACTION
• Tooth borne anchorage devices
like TPA and Expansion Screws
may lead to Dentoalveolar
compensatory changes like lose of
arch length, forward movement of
molars, proclination of max.
incisors, etc.
• Solution: Hydroxylapatite coated
Osseointegrated palatal onplant

VT’s
RETENTION OF CLASS III
• Class III malocclusion worsens with the continuing
mandibular growth.
• Relapse from continuing mandibular growth is likely to
occur and such growth is extremely difficult to control.
• Applying a restraining force to the mandible using a chin
cap is not effective in controlling growth in a class III
patient. In mild class III problems a functional appliance
or a positioner may be enough to maintain the occlusal
relationship during post treatment growth.

VT’s
• Wilford et al in their literature review attributed few
identifiable & unavoidable factors to relapse in class III
individuals:
– Unstable presurgurgical orthodontics
– Condyle being forces posteriorly into the fossa
– Occlusal splints that open the bite and create an
upward and forward rotation of the mandible on
splint removal
– Failure to remove the bony interferences from
proximal segment that do not allow the segments to
fit passively
– Macroglosia
– Untreated active condylar hyperplasia.

VT’s
CONCLUSIONS
• To improve skeletal discrepancy and provide a more favorable
environment for future growth. But this may prove
detrimental for long term stability of the case.
• Early orthopedic treatment using face mask or chin cup
therapy improve skeletal relations which in turn minimizes
excessive dental decompensation.
• Early treatment provides more pleasing facial profile, thus
improves psycho-social development of child.
• It eliminates Orthognathic surgery maximizing growth
potential of maxilla may minimize the extent of surgical
procedures in cases of severe Class III malocclusion.
• “Correct diagnosis and proper treatment planning holds the
key to successful outcome of the case.”

VT’s
References
• Contemporary orthodontics: William R. Proffit
• Early orthodontic treatment: J Daniel Subtenly
• Orthodontics current principles and techniques: T.M Graber, Vanarsdal, Vig
• Biomechanics and esthetic strategies in Clinical Orthodontics: Ravindra Nanda
• Text of orthodontics: Samier Bishara
• Graber Petrovic Rakosi
• Seminar in orthodontics 2005 – EARLY TREATMENT
• AJODO 2006 Apr Suppl.
• Int’l J of adult ortho & orthga surgery: 2001
• Ngan P et al: AJODO : 1996
• Ngan P et al: Pediat Dent : 1997
• AJO DO 2005 128; 299-309
• Kalha A S: EBD 2006:7,16-17
• JCO 1997 – 2 PIECE CORRECTOR FOR CLASS III
• Garatinni et al AJODO 1998
• J Ind. Ped & Prev Dent: 1998 – Uteraja et al
• East Mediters Health J: 2006: Danaie et al

Class iii malocclusion

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