1. JITESH HARYANI
CLASS III
MALOCCLUSION

2. CONTENTS
 Definition
 Classification
 Prevalence
 Etiology
 Growth pattern in class III
 Components of class III malocclusion
 Differential diagnosis
 Treatment planning
 Treatment modalities
 Retention

3. DEFINITION
 According to ANGLE
(1899) class III
malocclusion is defined as
class III molar relation
with the mesio – buccal
cusp of the maxillary first
permanent molar occluding
in the inter dental space
between the mandibular
first and second molars. Or
lower permanent molar is
ahead of the upper first
molar by a distance of the
width of a premolar or even
more in extreme cases .

4. CLASSIFICATION
1. Tweed (1966) divided Class III malocclusion into
two categories –
 Pseudo class III : normally shaped mandibles (L
shaped) and under developed maxilla.
 Skeletal class III : large mandibles.

5. 2. Moyers (1997) :
 Osseous
 Muscular
 dental

6. 3. Park and Baik (2001) classified class III based on
position of maxilla relative to the craniofacial
skeleton. :
 Type A : individuals have a normal maxilla and
overgrown mandible. This is true mandibular
prognathism

7.  Type B : maxillary and mandibular excess, but
mandible grows more than maxilla. They have a
acute nasolabial angle
 Type C : hypoplasia of maxilla; their facial profile is
concave with large nasolabial angle, which is
frequently camouflaged by dentoalveolar
compensations.

8. PREVALENCE
The frequency of class III malocclusion varies among
different ethnic groups.
 Caucasians : 1%-4%
 African Americans : 5%-8%
 Hispanic : 4%- 14%
 Indians : 3.4% (Kharbanda et al, 1995)

9.  Only few studies have seperated pseudo and true
class III for prevelance.
 According to a study by Lin (1985), prevelance of
class III malocclusion in chinese children between 9-
15 years.
-pseudo class III : 2.3%
-true class III : 1.7%

10. ETIOLOGY
Class III skeletal growth has a multifactorial basis that
is influenced by :
Genetics
Environment
Gene- Environment interaction

11. GENETIC INFLUENCE
 Genetic influence can be studied under two main
headings : (Chaturvedi et al, VJO 2011)
1. MODE OF INHERITANCE IN CLASS III
MALOCCLUSION :
“Hapsburg Jaw” - Strohmayer (1937)
concluded that mandibular
prognathism in this family was
transmitted by an autosomal
dominant trait

12.  Suzuki (1961) studied offspring of parents with
mandibular prognathism from 243 Japanese families,
and reported a frequency of 31% of this condition if the
father was affected, 18% if the mother was affected and
40% if both parents were affected.
 Polygenic hypothesis : Litton et al (1970)
 Manfredi et al (1997) found strong genetic control in
vertical parameters and in mandibular structure in twins.

13. 2. ROLE OF GENES IN EXPRESSION OF CLASS
III MALOCCLUSION
 Condylar cartilage grows in response to functional
stimuli or mechanical loading. This in turn leads to
mandibular growth.
 McNamara and Carlson hypothesized that class III
malocclusion might be precipitated under these
biomechanical conditions by the inheritance of genes
that predispose to a class III phenotype.

14.  Genes involved in mandibular prognathism :
VEGF
IGF – 1
HOX – 3
Ihh and Pthlh (Rabie et al)
COL2A1

15. Craniofacial anomalies
 Cleft lip and palate
 Crouzan syndrome
 Apert syndrome
 Downs syndrome
 Binder’s syndrome

16. ENVIRONMENTAL FACTORS
 Enlarged tonsils (Angle; 1907)
 Hormonal disturbances (Downs; 1928)
 Posture (Gold; 1949)
 Nasal blockage (Davidov; 1961)
 Congenital anatomic defects (Monteleone; 1963)

17.  Large tongue as in the case of thyroid deficiency can
contribute to a mandibular prognathism by causing the
mandible to be positioned forward all times.
 Rakosi and Schilli suggested mouth breathing in the
etiology of class III malocclusions.
 Acute cranial base angle and anterior positioned
glenoid fossa : Ellis and McNamara (1984) and Singh
et al (1997)

18. GROWTH PATTERN IN CLASS III
MALOCCLUSION
 Sugawara and Mitani (1997) reported that a class III
skeletal pattern is developed at a young age and does
not change fundamentally.
 However long term growth studies in untreated class
III individuals have suggested that the class III
pattern worsens with age. (Deguchi et al)

19.  Battagel showed a sexual dimorphism in growth of
class III subjects.
 Baccetti et al (2007) conducted a longitudinal study
in untreated class III subjects based on CVM staging.
They concluded that there is persistence of typical
Class III growth characteristics well beyond the
adolescent growth spurt into early adulthood.

20.  There is active mandibular growth, absence of
any catch-up growth in the maxilla, and the
significantly more vertical direction of facial
growth during late adolescence

21. COMPONENTS OF CLASS III
MALOCCLUSION
 The components of class III malocclusion can be
grouped into :
1. Mandibular prognathism
2. Maxillary retrognathism
3. Dental retrusion or protrusion
4. Combinations of above
5. Pseudo class III or functional class III

23.  According to Guyer et al, mandibular prognathism
and class III malocclusion are not synonymous.
 Infact mandibular prognathism as a primary cause of
class III was found in only 19 % cases.
 Ellis and McNamara calculated 243 possible
combinations of class III malocclusion.

24. DIAGNOSIS OF CLASS III
MALOCCLUSION
 In evaluating the Class III relationship during the
primary or mixed dentition period, it is important to
consider whether the problem is dentoalveolar or
skeletal in origin.

25. Dental assessment
Functional assessment
Profile assessment
Cephalometric assessment

27. Diagnostic criteria for pseudo class III
malocclusion. (Rabie et al AJODO 2000)
 Majority showed no family history.
 Class I molar and canine relationships at HO and
Class II or end to end relationship at CR.

28.  Decreased midface length.
 Forward position of the mandible with normal
mandibular length.
 Retroclined upper incisors and normal lower
incisors.

29. PROFILE ASSESSMENT
 Assess facial proportions, chin position, mid face position and
vertical proportion (Turley et al)
• Check vertical proportion in CR and CO
• The normal vertical proportion ratio of lower face to total
face height is 55%
• Reduced in patients with functional shift and overclosure

30. CEPHALOMETRIC ASESSMENT
 The following distinctions can be made in
categorizing the class III sagittal relationship:
 Class III malocclusion with dentoalveolar
malrelationship.
 Class III malocclusion with a long mandibular
base.
 Class III malocclusion with an underdeveloped
maxilla.
 Class III malocclusion with combination of
underdeveloped maxilla and prominent
mandible; horizontal or vertical growth pattern.
 Class III malocclusion with tooth guidance or
pseudo-forced bite.

31. CLASS III MALOCCLUSION WITH
DENTOALVEOLAR MALRELATIONSHIP
 No basal sagittal
discrepancy.
 ANB within normal
limits.
 Problem primarily
concentrated in incisal
relationship, with
maxillary incisors tipped
lingually and mandibular
incisors tipped labially.

32. CLASS III MALOCCLUSION WITH A LONG
MANDIBULAR BASE
 SNA normal with larger
SNB , creating a negative
ANB difference.
 More obtuse gonial angle .
 Anteriorly positioned
mandible with larger
mandibular length.
 More obtuse mandibular
plane angle.

33.  Tongue morphology is flattened ; whereas tongue is
postured forward and lies lower in the mouth.
 The upper incisors are labially tipped, and the lower
incisors are inclined lingually.

34. CLASS III MALOCCLUSION WITH AN
UNDERDEVELOPED MAXILLA
 SNA smaller than normal
with normal SNB ,
creating a negative ANB
difference.
 The effective length of
maxilla is shorter.
 Favourable initial
inclination of incisors.

35. CLASS III MALOCCLUSION WITH COMBINATION OF
UNDERDEVELOPED MAXILLA AND PROMINENT
MANDIBLE
 Smaller SNA with shorter
maxillary base length.
 Larger SNB with longer
mandibular base length.
 Depending on ramal length
: two types
Short ramus : vertical
pattern, large gonial angle.
Long ramus : horizontal
pattern, smaller gonial
angle.

36. Cephalometric characteristics of pseudo class III
 Most of the cephalometric measurements is an
intermediate form between Class I and skeletal Class
III. (Kwong and Lin)

37.  Measurement of the gonial angle in the pseudo Class
III sample is found to be rather similar to the Class I
sample, making this measurement a key diagnostic
feature in the differential diagnosis between pseudo
and skeletal Class III malocclusions.

38. DIAGNOSTIC CHARACTERISTICS OF AN
UNFAVOURABLE CLASS III GROWTH
38
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.
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.

39. TREATMENT PLANNING FOR CLASS III
MALOCCLUSION
 The therapeutic possibilities of class III
malocclusion depends upon :
 The developmental age of the patient
 The nature of malocclusion.

40.  There are three main treatment options for skeletal
class III malocclusion:
Growth modification,
Dentoalveolar compensation (orthodontic
camouflage), and
Orthognathic surgery.

41. SUGAWARA et al 2002

42. TWO MAIN DILEMMAS
 ONE PHASE V/S TWO PHASE THERAPY
 CAMOUFLAGE V/S SURGERY

43. EARLY TREATMENT OF SKELETAL
CLASS III MALOCCLUSION:43
 The “Doctrine of limitations” was in full swing in the 40”s
and 50”s. Early treatment was condemned except for serial
extractions.
 But evidence based researches have led to many favorable
conclusions for early treatment. Class III malocclusion, in
particular gets the nod from many authors in favor of early
treatment .Starting with Tweed, treatment timings can be as
early as 4 years of age.

44. Timing of early class III treatment

45. 45
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.

46. 46
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.

47. Studies showing greater maxillary protraction in
early treatment of class III
 Irie and Nakamura – 1975
 Profitt – 1986
 Nakada et al – 1993
 Kapust et al – 1998
 Baccetti et al – 1998
 Franchi , Baccetti and McNamara - 2004

48. Studies which concluded no difference in early or
late treatment of classIII
 Baik – 1995
 Baik and Sung 1998
 Yuksel et al 2001
 But none of these studies evaluated the long term
effect of early class III treatment

49. Long term effect of early class III treatment
 Despite the known influence of early treatment on
the facial appearance of growing patients with
skeletal Class III malocclusion, few comparative
reports on the long-term effects of different
treatment regimens (1-phase vs 2-phase treatment)
have been published.

50.  In a case report presented by Sugawara and Nanda
(AJODO 2012), they compared the effects of early
orthodontic intervention as the first phase of a 2-
phase treatment vs 1-phase fixed appliance
treatment in identical twins over a period of 11
years.
 They reported that inspite of the different treatment
approaches, both their patients showed identical
dentofacial characteristics in the retention phase.

51.  They concluded that :
 Early treatment had no impact on jaw growth in the
pubertal growth period.
 The criteria for the selection of 1-phase or 2-phase
treatment depend entirely on the patient’s
requirements. Because the biologic outcome is the
same

52. Prediction of class III growth pattern
 One of the reasons clinicians are reluctant to render
early orthopedic treatment in Class III patients is the
inability to predict mandibular growth.
 Discriminant analysis of long-term results of early
treatment identified several variables that had
predictive values.

53.  Franchi et al found the inclination of the condylar
head, the maxillomandibular vertical relationship
together with the width of the mandibular arch could
predict success or failure of early Class III treatment
 Ghiz et al found that the position of the mandible,
the ramal length, the corpus length, and the gonial
angle can predict successful outcomes with 95%
accuracy.

54. GTRV analysis
(Growth Treatment Response Vector)
3/8/2015 3:04 PM
54
 This analysis helps in determination of the
individual growth rate and direction. Lateral
cephalometric radiographs are taken after
facemask treatment and during the 3 to 4-year
follow-up visit.

55. 55
 The horizontal growth
changes of the maxilla and
mandible between the
posttreatment and follow-
up radiographs are
determined by locating A-
point and B-point on the
posttreatment radiograph
• Occlusal plane (O) constructed by using
mesiobuccal cusp of maxillary molars and
incisal tip of maxillary incisors as landmarks.

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 The first tracing was superimposed on the
follow-up radiograph by using the stable
landmarks on the midsagittal cranial
structure. A-point and B-point on the follow-
up radiograph were located, and the lines AO
and BO were then constructed by connecting
points A and B on the follow-up radiograph to
the occlusal plane of the first tracing.

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 The distance between the A-point on the 2 tracings
along the occlusal plane represents the growth
changes of the maxilla, and the distance on the
occlusal plane of B-point represents the growth
changes of the mandible

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 The GTRV ratio was calculated by using the
following formula:
This ratio and vector analysis provides information
on growth rate and direction and helps clinicians
to decide whether the Class III malocclusion can
be camouflaged by orthodontic treatment or
whether a surgical treatment is warranted.

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 The GTRV ratio of an
individual with normal growth
pattern from age 8 to 16 is
calculated to be 0.77
 GTRV ratio - 0.33 and 0.88 can
be successfully camouflaged.
 GTRV ratio - below 0.38
should be warned of the future
need for orthognathic surgery.

60. Camouflage v/s surgery – The borderline case
 Cassidy (AJODO 1993) defined “borderline cases” as
those patients who were similar with respect to the
characteristics on which the orthodontic/surgical
decision appeared to have been based.

61.  Kerr et al(BJO 1992) established some cephalometric
yardsticks in adult patients with class III malocclusion to
find objective criteria for treatment options. These
researchers suggested that surgery should be performed
for patients with
 an ANB angle of less than -4°, a
 maxillary/mandibular (M/M) ratio of 0.84,
 an inclination of the lower incisors to the mandible of
83°
 and a Holdaway angle of 3.5°.

62.  Discriminate analysis has shown that Wits appraisal
is most decisive in distinguishing camouflage
treatment from surgical.
 Average Wits for camouflage = -4.6±1.7mm
 For surgical treatment it was = -12.1±4.3mm
(Eisenhauer AJODO 2002)

63.  Musich (2007) : 3 categories
 Green - Wits < 4mm (camouflage)
 Yellow – Wits 4-8mm (borderline)
 Red – Wits >12mm (definite surgical)

64.  Rabie et al (2008) suggested that Holdaway angle
can be a reliable guide.
 The threshold value was 12°., a Holdaway angle of
>12° can successfully be treated by camouflage.

65. Treatment of class III
malocclusion

66. Treatment strategies for developing skeletal
class III patients
 Treatment modalities include:
Chin cup therapy
Functional appliance therapy
Maxillary protraction by conventional face mask
therapy
Maxillary protraction by SAS

67. Treatment approach non growing class III
patients
 Camouflage with conventional fixed appliances
 Camouflage with SAS
 Orthognathic surgery

68. Chin Cup Therapy
 In the late 1940’s and early 1950’s after observation
of the gross effects of Milwaukee brace treatment on
the growth and form of the mandible, it was
proposed that strong “orthopedic” forces in the range
of 400 to 800 gm.
 A chin cup or mental anchorage serves to redirect
mandibular growth

69. Force Magnitude and Direction
 Chin cups are divided into two types:
 Occipital-pull chin cup that is used for patients with
mandibular protrusion and
 Vertical-pull chin cup that is used in patients presenting
with a steep mandibular plane angle and excessive anterior
facial height.
 Most of the reported studies recommended an orthopedic
force of 300 to 500 g per side.

71.  Patients are instructed to wear the appliance 14
hr/day.
 The orthopedic force is usually directed either
through the condyle or below the condyle.

73. Effects of Chin Cup Therapy
 Redirection of mandibular growth at the chin.
 Backward repositioning of the mandible.
 Retardation of mandibular growth at the condyle.
 Remodeling of mandibular morphology at the gonial
angle and symphysis.

75.  Evidence exists that treatment to reduce mandibular
protrusion is more successful when it is started in the primary
or early mixed dentition.
 The treatment time varies from 1 year to as long as 4 years
depending on the severity of the original malocclusion.
 Stability of Treatment
 The stability of chin cup treatment remains unclear. Several
investigators reported stability in horizontal maxillary and
mandibular changes associated with chin cup treatment.
 However, a few studies reported a tendency to return to the
original growth pattern after the chin cup is discontinued.

76.  Sugawara et al published a report on the long-term
effects of chin cup therapy on three groups of Japanese girls
who started chin cup treatment at 7, 9, and 11 years with
serial lateral head films
 The authors found that the skeletal profile was greatly
improved during the initial stages of chin cup therapy, but
these changes were often not maintained, due to catch-up
mandibular displacement.
 They concluded that chin cup therapy did not necessarily
guarantee a positive correction of the skeletal profile after
completion of growth, which suggests the need for the
extended use of the chin cup over the growth period.

77.  Chincap therapy is applicable when a growing
patient has a true skeletal Class III malocclusion
and a large mandible; lacks maxillary recession, an
acute cranial base angle, a long-face syndrome, and
symptoms of temporomandibular disorders; and
orthognathic surgery is not an option.
 Treatment must continue until growth has ceased
to prevent redevelopment of the prognathic face
after chincap therapy, and some overcorrection
might be warranted
Hideo Mittani AJODO JUNE 2002

78. Functional appliances

79. THE FUNCTIONAL REGULATOR (FR-3)
OF FRANKEL79
INDICATION:
used during the deciduous,
mixed, and early permanent
dentition stages to correct
Class III malocclusion
characterized by maxillary
skeletal retrusion, and not
mandibular prognathism.

80. Mechanism

81.  FR – 3 can also be used as a retainer after class III
correction by protraction face mask (Petit) or
orthognathic surgery (Eirew)

82. Bionator III appliance
Levrini et al (1993) modified balter’s bionator for
class III .The new application has
1.Deeper and wider lingual wings.
2.Acrylic vestibular lateral shields extending deeply to
upper formix.
3.Upper labial buttons.
4.Upper incisior inclined plane.

83. According to Garrattini et al (AJO 1998)
bionator is an effective appliance in mid facial
deficiency especially with hypo divergent
growth pattern.
The control of mandibular growth is
unpredictable with this appliance. The
dentoalveolar chances exceeded the skeletal
effects of bionator III.

84. REVERSE TWIN BLOCK
84
 Functional correction of Class III malocclusion is achieved
in Twin Block technique by reversing the angulations of the
inclined planes cut at 70° angle, drive the upper teeth
forwards by the forces of occlusion and restrict forward
mandibular development.

85. 85
Effects of RTB: (Kinder etal. JO.2003;30:197 201)
 Mainly dentoalveolar.
 Proclination of the maxillary incisors (mean: 5.1°)
 Retroclination of the mandibular incisors (mean:
4.5°)
 Downward and backward mandibular rotation.
 Increase in lower facial height (mean: 1.75mm)
 Reduction in mandibular prognathism (mean:
−1.3°).

86. 86
 The average reported treatment time for these
patients was 6.6 months—significantly shorter than
the 3.1 years reported by Loh and Kerr with the use
of a Function Regulator III appliance.
 Treatment duration is usually 6-9 months.

87. RTB v/s Protraction facemask therapy
87
A comparison of two different techniques for early
correction of Class III malocclusion
(Seehraa etal. AO. 2012;82:96–101 )
 Both appliances are capable of correction of Class III
dental relationships; however, the relative skeletal
and dental contributions differ. Skeletal effects,
chiefly anterior maxillary translation, predominated
with PFM therapy. The RTB appliance induced Class
III correction, primarily as a result of dentoalveolar
effects.

88. Protraction face mask
 Initially in 1944 Oppenhim suggested moving the
maxilla in an attempt to counterbalance mandibular
protrusion.
 Later Delaire in 1960’s revived the interest in use of
protraction facemask which was further modified by
Petit in 1983

89. Indications
 Mild to moderate skeletal class III with retrusive
maxilla.
 Hypodivergent growth pattern

90. Appliance design
 The orthopedic face mask system has three basic
components the facemask, maxillary splint, and
elastic.
 The Facemask: The protraction facemask is a one-
piece construction consisting of a forehead pad , a
chin pad connected with a heavy steel support rod
and a adjustable anterior wire and hooks to
accommodate a downward and forward pull of the
maxilla with elastics

92. PARTS OF PETIT FACE MASK
92

93. Petit face mask lateral and frontal view
93

94. Maxillary splint:
The maxillary splint stabilizes the maxilla as a single unit.
 In primary dentition it is advisable to use acrylic bonded
palatal expansion appliance with 0.040’’ wire framework
extending around the buccal and lingual surface of the
dentition with hooks extending buccally at the level of
the first deciduous molars for attachment of elastics
 In mixed or early permanent dentition banded palatal
expansion appliance is constructed with 0.045 inch wire
extending bilaterally and hooks extending bucally in the
canine region.

95.  The splint is activated twice per day for 2 weeks or
more depending on discrepancy
 In patients whom no increase in transverse
dimension is desired appliance is still activated for 8-
10 days .

97. 97
SEQUENCE OF ELASTICS:
 Initially 3/8” 8 oz
 After 2 weeks 1/2” 14 oz
 Increased to a max of 5/16” 14 oz
Young patients (4-9) years should wear the mask on a full
time basis except during meals. Duration is 4-6 months.
They can be retained with only night time wear or with a
maintenance plate, chin cup or FR III. In older patients, it is
worn at all times except during school.

98. When is the best time to start protraction facemask
treatment?
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98
 The optimal time to intervene a Class III
malocclusion is at the time of the initial eruption of
the maxillary incisors. (MacNamara)
 A positive overjet and overbite at the end of the
facemask treatment appears to maintain the
anterior occlusion.
 Biologically, the circummaxillary sutures are
smooth and broad before age 8 and become more
heavily interdigitated around puberty

99. Treatment effect of protraction facemask
 Maxillary forward displacement : increase in SNA
angle.
 Mandibular downward and backward rotation:
decrease in SNB angle, increase in SN-MP angle .
 Increase in anterior facial height .
 Labial inclination of upper incisors .
 Lingual inclination of lower incisors.

102.  The following four components of force system are
important for the protraction headgear:
The magnitude of force:
 The force value used for maxillary protraction
ranges from 200-800 gm.per side.
The sutural anatomy and the age of the patient play a
major role in determining the amount of force
needed to bring the maxilla forward with protraction
force.

103.  Preadolescent patient ( 4-8 years): 200-250 gm per
side.
 Early adolescent patient ( 8-11 years): 300-450 gm
per side.
 Late adolescent patient (>11 years ): 450-600 gm per
side.

104.  Direction and point of force application:
 Nanda and Hickory speculated that the center of
resistance of the mid face is 5-10 mm below the orbitale
on the zygomatic bone
 Miki supported it with adding the vertical direction that
it was between orbitale and distal root apex of maxillary
first molar.
 Hata et al and Lee et al reported that line of force 5mm
above the palatal plane and 15 mm above occlusal plane
did not result in counter clockwise rotation of maxilla

105.  The vertical dimension of
the face can be controlled
by changing the point of
force attachment .

106. Clinical response to maxillary protraction :
 Total 3-16 month.
 Anterior crossbite is corrected in 3-4 months while
molar relation and overbite correction in additional
4-8 months

107. 107

108. PROTRACTION WITH AND
WITHOUT RME:
 In patients whom no increase in transverse
dimension is desired , the appliance should be still
activated for 8 - 10 days to disrupt the maxillary
sutural system and to promote maxillary protraction
( Hass ,1965)
 Numerous authors have reported on the anterior
constriction of the maxilla when it is protracted and
emphasize the necessity of physically expanding the
maxilla before protraction.

109.  Palatal expansion alone has also been shown to
facilitate correction of a Class III malocclusion by
causing a downward and forward displacement of
the maxilla.
 Palatal expansion has been noted not only to affect
the intermaxillary suture, but also all of the circum-
maxillary articulations. It has also been suggested
that palatal expansion ‘disarticulates’ the maxilla,
initiating a cellular response which then allows a
more positive reaction to protraction forces .

110.  Baik et al (1997) found that forward movement of
point A was more in exapansion group (2mm) than
in labiolingual group (0.9mm)
 Kim et al (1999) evaluated facemask therapy in a
meta-analysis study and reported that the results of
protraction with or without expansion were similar,
but the average duration of treatment was longer in
the nonexpansion group.

111.  Vaughn et al (AJODO 2005) in a RCT study
concluded that palatal expansion makes NO
difference in the amount of anteroposterior skeletal
change.
 Turtop et al (SIO 2007) showed that skeletal change
in both groups were same, but there was increased
molar eruption in non expansion group.

112.  Valiathan et al (AJODO 2009) in a finite element
study showed that high stresses generated in various
craniofacial sutures after maxillary protraction with
expansion are responsible for disrupting the
circummaxillary sutural system and presumably
facilitating the orthopedic effect of the facemask.

113. The Modified Tandem Appliance
 Klempner [JCO2003]
 Designed for Class III patients with skeletal
midfacial deficiencies. The MTA has three
components, one fixed and two removable.
 The upper fixed appliance can be a traditional
maxillary expander, with or without palatal acrylic.
Soldered buccal arms are used for elastic traction.

114.  Upper brackets can be added, depending on the
patient’s age and clinical situation.
 The lower appliance comprises a remov-able acrylic
retainer with posterior occlusal coverage and buccal
headgear tubes embedded in the area of the lower
first molars
 . An .045" headgear facebow with the outer bows
bent out for elastic attachment is inserted into the
lower tubes.

116. Advantages :
 Promotes patient compliance, because it is more esthetic
and comfortable than extraoral appliances.
 Promotes good oral hygiene, because it is removable.
 Allows early treatment of any Class III malocclusion,due to
optimal retention in the decidu-ous,mixed, or early
permanent dentition.
 Distributes the force of protraction to all maxillary teeth.
 Permits free mandibular movement, with its polished
occlusal surface, so that a functional shift is easily
corrected.

117. Protraction by skeletal anchored system
 Two methods :
 1. bone anchored intra oral class III elastics. (De
Clerk et al 2009)
 2. bone anchored face mask therapy (Cevidanes et al
2010)

121. ORTHODONTIC CAMOUFLAGE
 Essentially two main approaches are used once the
case is selected for camouflage.
1. Nonextraction approach
a) The MEAW technique
b) Lower arch Distalisation using TADs
2. Extraction approach

122.  It is commonly believed that successful camouflage
treatment for class III malocclusion can be achieved
by :
 proclination of maxillary incisors,
 retrusion of mandibular incisors,
 downward and backward rotation of mandible.
 Distalisation of mandibular dentition

123.  The multiloop edgewise archwire (MEAW, 0.016 ×
0.022 Inch), multiple L-loops and tip-back bends,
incorporated in the MEAW together with
intermaxillary elastics can allow individual tooth
movements and make it possible to upright
posterior teeth, to change the inclination of the
occlusal planes, to correct the occlusal sagittal
relationship, and to obtain the correct intercuspation

124.  The use of MEAW requires completion of all
alignment and levelling and constant use of vertical
anterior elastics.
 Studies suggest that improvement in molar
relationship and overjet was achieved with upright
and distal movement of the lower posterior teeth.

125. Distalisation of mandibular dentition
 Chung et al , 2004

126. EXTRACTION APPROACH :

127.  LIMITATIONS FOR INCISOR MOVEMENT BY
CAMOUFLAGE : (Burns et al, 2010)
 Upper incisor to SN – 120°
 Lower incisor to MP - 80°

128. Orthognathic surgery
 Ricketts described eight major characteristics of
surgical class III case :
1. Open basion – nasion to FH plane angle (average
27°)
2. Closed Xi axis (average 15°)
3. Obtuse corpus condyle axis
4. Long condyle neck

129. 5. Long corpus
6. Short porion distance from pterygoid vertical
7. Short anterior cranial length on basion – nasion
8. Concave profile

130. Retention of class III
130
 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 a mandible as from
chin cap is not effective in controlling growth in a
class III patient

131.  In mild class III problems a functional appliance or a
positioner may be enough to maintain the occlusal
relationship during post treatment growth.
 Bonded retainers in case of lower incisor extraction
are generally required.

132. REFERENCES
 Bishara SE. Textbook of orthodontics. Philadelphia: W.B.
Saunders; 2001.
 Peter Ngan ; Early “Timely” Orthodontic Treatment, SIO
SEPTEMBER 2005 :VOL 11, NO 3
 Guyer EC, Ellis EE, McNamara JA, et al. Components of Class III
malocclusions in juveniles and adolescents. Angle Orthodontist
1986; 56: 7-30.
 Tortop T, Keykubat A, Yuksel S. Facemask therapy with and
without expansion. American Journal Orthodontics and Dentofacial
Orthopedics 2007,132: 467–474
 Sugawara, J.; Asano, T.; Endo, N.; and Mitani, H.: Long-term
effects of chincap therapy on skeletal profile in mandibular
prognathism, Am. J. Orthod. 98:127-133, 1990.
 Joondeph DR: Early orthodontic treatment. Am J Orthod
Dentofacial Orthop 104:199-200, 1993

133.  Rabie ABM, Wong RWK, Min GU. Treatment in borderline Class
III malocclusion: orthodontic camouflage (extraction) versus
orthognathic surgery. Open Dent J 2008;2:38-48.
 Burns R et al. Class III camouflage treatment: What are the limits?
Am J Orthod Dentofacial Orthop 2010;137:9.e1-9.e13
 Ghiz M, Ngan P, Gunel E. Cephalometric variables to predict future
success of early orthopedic Class III treatment. Am J Orthod
Dentofacial Orthop 2005;127:301-6.
 McNamara JA Jr, Brudon WL. Orthodontic and orthopedic
treatment in the mixed dentition. Ann Arbor, Mich: Needham Press;
1993.
 Litton SF, Ackermann LV, Isaacson RJ, et al: A genetic study of
Class III malocclusion. Am J Orthod 58:565-577, 1970
 Ngan P: Biomechanics of maxillary expansion and protraction in
Class III patients. Am J Orthod Dentofacial Orthop 121:582-583,
2002

134. THANK YOU