Treatment of Class 3 malocclusion /certified fixed orthodontic courses by Indian dental academy

TREATMENT OF
CLASS III MALOCCLUSION

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


“Class III malocclusion occurred when
the lower teeth occluded mesial to their
normal relationship the width of one
premolar or even more in extreme
cases”.
-

Angle (1899)


CLASSIFICATION
• TWEED (1966)
CLASS III MALOCCLUSION

PSEUDO CLASS III

SKELETAL CLASS III

Normal Mandible

Large Mandible

Underdeveloped
Maxillae

Underdeveloped or
Normal Maxillae


•MOYERS
ACCORDING TO THE CAUSE :
Osseous
Muscular
Dental

Anterior Positioning : Tooth contact relationship which
force the mandible into a forward position.(Pseudo Class III)


• FREQUENCY OF CLASS III MALOCCLUSION
7 to 13 Years
1) Caucasians

1 to 4 %

2) African – Americans
3) Asian

14 to 18 Years
5 to 8%

Maxillary deficiency

4) Japanese

4 % Younger / 14 % Older

5) Chinese

3 % Younger / 13 % Older

4.2%
9.4%

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.
 Functional factors – Anteriorly positioned tongue
believed to be a local epigenetic factor.
 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.


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

DENTAL ASSESSMENT FOR DIAGNOSING CLASS III MALOCCLUSION


Class III Skeletal Growth Pattern
1) Cranial Base
 Angle – More Acute
 Middle Cranial Fossa  Posterior and Superior
Alignment
2) Maxilla
 Decreased horizontal maxillary growth when
compared with the patients with class I
malocclusion.
3) Mandible
 Gonial Angle  Obtuse
 Anteriorly placed
 Dentoalveolar compensation  Proclination of
upper incisors, Retroclination of lower incisors.

Indication and Contraindication for
Early Class III treatment
TURPIN et al (1981)
Positive Factors :

Good Facial esthetics
Mild skeletal disharmony
No familial prognathism
Ant-Post functional shift
Convergent facial types

Negative Factors : Poor facial esthetics
Severe skeletal disharmony
Growth complete

Treatment of Pseudo class III
Malocclusion
Clinical Features :
 Anterior cross bite with premature tooth
contact with CO-CR discrepancy
Treatment :
1) Reverse SS crown
2) Tongue Blade
3) Fixed Appliance

Treatment of Skeletal class III malocclusion
1) Pre-Adolescence (Growth Remaining)
a) Functional Appliance Therapy
 Frankel III regulator
Two separate studies concluded ;
1) Dento alveolar effect
2) Downward and Backward rotation of
Mandible

CHIN CUP THERAPY
 Indication  Normal maxilla and prognathic
mandible
 Effect of Mandibular growth
• Redirection of Mandibular growth vertically
• Backward repositioning of mandible
• Remodeling of mandible with closure of
gonial angle.
 Effect of Maxillary Growth


Force magnitude and Direction
TYPES
• Occipital Pull
• Vertical Pull
Orthopaedics force of 300-400 grams / 14 hours a day.

Treatment Timing
Primary to early mixed dentition

Stability
Sugarwara et al :- Though skeletal changes were
greatly improved initially they were however not
maintained.

FACE MASK THERAPY

Delaire et al , (1960) : Revived interest in using
face mask for Maxillary protraction
Petite : Later modified Delaire’s concept by
increasing the force and thus decreasing the
treatment time.

COMPONENTS

Forehead Pad
Midline frame work

Hooks
Chin Pad

Maxillary protraction below centre of
resistance produces anticlockwise
rotation of the maxilla

Protraction elastics attached near the
maxillary canine with a downward and
forward pull of 30 degrees to the
occlusal plane minimize bite opening.

Force : 300 to 600 grams per side depending on age.
Time : 10 to 12 Hrs / Day
Duration : 3 to 6 months


CONSTRUCTION OF ANCHORAGE SYSTEM
1) Metallic banded palatal expansion appliance
2) Acrylic bonded palatal expansion appliance

Skeletal Effect of Maxillary Protraction
Lacrimo Maxillary
Fronto maxillary

Naso Maxillary

Ethmomaxillary
Zygomatico maxillary

Zygomatico Temporal
Pterygo palatine

Intermaxillary

Cokish and Shapio ( 1979) :- Anticlockwise maxilla
- Clockwise rotation of mandible
Kambala et al (1977) : Maxilla displaced anteriorly with
changes in the circum maxillary sutures with forward and
downward movement of maxilla
Does it make a different if protraction was initiated during
expansion or after expansion ?
Beik (1984) : Found that greater forward movement of maxilla
was initiated during maxillary expansion
STABILITY :
- Effects on maxilla remain stable for 1 – 2 years after treatment
- In some studies maxilla and mandible reverted back to original
position.

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Treatment of Class 3 malocclusion /certified fixed orthodontic courses by Indian dental academy

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Treatment of Class 3 malocclusion /certified fixed orthodontic courses by Indian dental academy