CONTENTS

INTRODUCTION

DEFINITION

ETIOLOGY

FREQUENCY

CLASSIFICATION

CLINICAL EXAMINATION

GROWTH COSIDERATION

GOALS OF EARLY INTERCEPTIVE TREATMENT

TREATMENT OF PSEUDO CLASS III MALOCCLUSION

TREATMENT OF SKELETAL CLASS III MALOCCLUSION

CONCLUSION

REFERENCE

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.

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)

ETIOLOGY

GENITIC

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) environmental factors: Habits and mouth Breathing

Enlarged tonsils and naso-respiratory diseases.

Premature loss of deciduous molars:Results in anterior mandibular displacement.

TERATOGENS:

Cleft lip and palate result in maxillary deficiency in most occasions a

class III malocclusion is established. Teratogens causing cleft lip and

palate are aspirin, cigarette smoke (hypoxia), Dilantin, 6-

Mercaptopurine, valium etc

Vitamin D excess causes premature closure of sutures and

might lead to class III malocclusion

ACROMEGALY AND HEMI MANDIBULAR

HYPERTROPHY:

FREQUENCY

Caucasians - 1 to 4 %

African – Americans - 5 to 8%

Asians:

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)

CLASSIFICATION

Generally of 2 types:

Dentoalveolar

Skeletal

Mandibular protrusion

Maxillary retrusion

Combination

PSEDUO CLASS III

Malocclusion is produced by a forward movement of

mandible during jaw closure.

Also known as habitual or postural class III malocclusion.

Angles classification

The mesio – buccal cusp of the maxillary first

permanent molar occluding in the inter dental space

between the mandibular first and second molars.

Class III Modification of Dewey

MOYERS CLASSIFICATION

ACCORDING TO THE CAUSE

OSSEOUS

MASCULAR

DENTAL

CLINICAL EXAMINATION

EXRAORAL FEATURES:

A CONCAVE FACE,DEFICIENT MAXILLA OR PROMINENT CHIN.

MALAR DEFICIENCY RESULTING INTO FLAT FACE

INCREASED LOWER ANTERIOR FACIAL HEIGHT

ANATOMICALLY LARGE LOWER LIP LENGTH

INTRAORAL FEATURES

ZERO OR –VE OVERJET

NARROW MAXILLARY ARCH WITH CROWDING

UNILATERAL OR BILATERAL POSTERIOR CROSSBITE

PROCLINED MAXILLARY INCISORS

RETROCLINED MANDIBULAR INCISORS

LOW TONGE POSTURE

FLAT CURVE OF SPEE.

GROWTH COSIDERATIONS

Sugawara and Mitani :Reported similar increments

between patients with Class III and Class I malocclusions

during the prepubertal pubertal and postpubertal growth

periods.

Battagel :found that the largest increment of facial

growth for males occurred between the ages of 14 and 16

years.

whereas in female patients the maximum increment of

facial growth occurred between the ages of 9.5 to12 years,

although active growth continued in the nasal area and

both jaws after the age of 15 years.

Goals of early interceptive treatment

(1) preventing progressive, irreversible soft tissue, or

bony changes.

(2) improving skeletal discrepancies and providing a more

favourable environment for future growth.

(3) improving occlusal function;

(4) simplifying phase II comprehensive treatment

and minimizing the need for orthognathic surgery

(5) providing more pleasing facial esthetics

DIAGNOSTIC CRITERIA FOR PSEUDO CLASS III

TREATMENT OF PSEUDO CLASS III

MALOCCLUSION

Elimination of the CO-CR discrepancy.

REVERSE STAINLESS STEEL CROWNS.

TONGUE BLADE

INCLINED PLANES.

AUXILLARY SPRINGS

TREATMENT OF SKELETAL CLASS III MAL OCCLUSION.

FUNCTIONAL APPLIANCE THERAPY

FRANKEL III REGULATOR

The purpose of lip pad are threefold.

TO ELIMINATE RESTRICTIVE PRESSURE OF UPPER LIP ON

THE MAXILLA.

TO EXCERT PRESSURE ON THE TISSUE AND PERIOSTEAL

ATTACHMENTS FOR STIMULATING BONE GROWTH.

TO TRANSMIT UPPER LIP FORCE TO THE MAXILLA VIA THE

LOWER LABIAL ARCH FOR A RETRUSIVE STIMULAS.

The FRIII appliance can also be used as a retentive device

following maxillary protraction treatment.

FRIII appliance was constructed to maintain the antero-

posterior and transverse corrections until the maxillary

incisors were fully erupted with sufficient overbite to

maintain the Class III correction.

CLASS III OR REVERSED BIONATOR.

Encourage development of maxilla Bite opened

2mm for this purpose

Acrylic portion Extends incisally from canine to

canine behind the upper incisors

Acrylic is trimmed away by 1mm behind the

lower incisors to prevent the tipping

Palatal bar

Runs forward with loop extending as far as

dec 1st m or premolar

Function – tongue to contact anterior portion

of palate , encouraging forward growth of this

area.

Labial bow

In front of lower incisors

Wire slightly touches the labial surface lightly / it is at a

paper thickness away

Construction bite

Construction bite- taken in more retruded position so as to

allow labial movement of maxillary incisors &also to

exert restrictive force on lower arch.

CHIN CUP

Skeletal Class III malocclusion with a relatively normal

maxilla and a moderately protrusive mandible can be

treated with the use of a chin cup.

The objective of early treatment with the use of a chin cup

is to provide growth inhibition or redirection and

posterior positioning of the mandible.

Effects on Mandibular Growth

Redirection of mandibular growth vertically.

Backward repositioning (rotation) of the

mandible.

Remodelling of the mandible with closure of the

gonial angle

EFFECT ON MAXILLA

Uner,Yuksel,and Ucuncu (Eur J Orthod 17:135-141, 1995)

Showed that early correction of an anterior crossbite with

a chin cup appliance prevents retardation of antero-

posterior maxillary growth.

Sugawara et a1 (Am JOrthod Dentofacial Orthop 98:127-133, 1990.)

Compared the growth changes of patients after chin cup

treatment with control subjects and reported that, at age

17, the midface is more deficient in patients of the control

groups than in those of the treatment groups.

Force Magnitude.

CHIN CUP 2 TYPES

OCCIPITAL PULL CHIN CUP.

VERTICAL PULL CHIN CUP.

300-500g PER SIDE

14hr/day

PROTRACTION FACE MASK THERAPY

Extraoral appliance that utilizes rests on the

chin and forehead(and occasionally the cheek

bones) as anchorage for elastic traction, with

the purpose of orthopaedically protracting the

maxilla.

Glossary of Orthodontic Terms

The use of a protraction face mask was first

described more than 100yrs ago in 1875 by

Johnson et al.

1944, Oppenheim: reported that it is impossible

to move the mandible backward, but that it is

possible to bring the maxilla forward to

compensate for mandibular overgrowth when

treating Class III malocclusions.

Although the facial mask was developed over 100

years ago, this approach was used infrequently

until reintroduced by Delaire in early 1970’s

Petit 1983: modified the basic concept of Delaire

by increasing the amount of force generated by

the appliance and decreasing the total treatment

time

1987 McNamara: introduced the use of a

bonded expansion appliance with acrylic

occlusal coverage for maxillary protraction.

ANATOMICAL CONSIDERATIONS

Circum-maxillary Sutures

A. Frontomaxillary

B. Nasomaxillary

C. Zygomaticomaxillary

D. Zygomaticotemporal

E. Pterygopalatine

F. Intermaxillary

G. Ethmomaxillary

H. Lacrimomaxillary

Melsen 1975 AJOProffit 5th Edition

BIOMECHANICAL CONSIDERATION

The orthodontist must first decide, whether to protract with a clockwise moment on the maxilla, a counter clockwise moment, or no moment

.

If the patient has normal overbite and normal vertical proportions, protraction without any moment is indicated.

If the patient has an anterior open bite in addition to the maxillary deficiency, a clockwise moment should be used.

If the patient has a deep bite, a counter clockwise momentshould be chosen.

Staggers JCO 1992

FACE MASK COMPONENTS

Forehead Piece

Main Frame

Protraction Bar

Chin Cup

Centre of Resistance of Maxilla

The center of resistance of the maxilla was found to be 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.

Magnitude of Force

The sutural anatomy and age of the patient play a major role in

determining the amount of force needed to bring the maxilla forward

with the protraction forces.

Preadolescent patient (5-8yr) – 200-250gm

Early adolescent patient (8-11yr) – 300-350gm

Late adolesent patient (12yr and above) – 450-600gm

Bishara

Duration of Force

Most of the studies done recommend a minimum of

10-12 hours/day preadolescents

12-16 hours/day adolescents

McNamara Brudon

Treatment Timing

Takada et al EJO 1993 : Reported that face mask treatment is most

effective in prepubertal patients (mean age, 7.8 years) and pubertal

patients (mean age, 10.3 years) and becomes less effective after late

puberty.

Baccetti 1998: Showed that treatment of class III malocclusion with

bonded maxillary expander and face mask in the early mixed dentition

results in a more favourable craniofacial changes than treatment in

late mixed dentition

Turley 1998 AJODO: Cephalometric effects of face

mask/expansion therapy in Class III children: a

comparison of three age groups (4-7 years, 7-10 years, 10-

14 years)Most effective in younger age groups but

significant change in older groups too.

Franchi AJODO2004: it was shown that significant

maxillary advancement could be achieved orthopedically

only by treating Class III patients during the deciduous or

early mixed dentition phases.

DESIGNS

Delaire mask was popularized to protract

the maxilla in 1978

In this appliance design,

Extraoral anchorage regions were the chin

and forehead.

The intraoral part of the appliance was

constructed with 1 mm stainless steel

arches (buccal and lingual) soldered to

the upper molar bands, which were

cemented to the anchor teeth (1st

permanent or 2nd deciduous molars).

McNamara Brudon

The protraction elastics were attached

between theanterior hooks (facing the

distal side of the lateral incisors) soldered

on the intraoral arch, with the hooks on the

Pre labial arch of the mask placed at the

level of the labial commissural line.

To avoid an opening of the bite, the force,

which delivers about 400 g of force on

each side was directed downward about

20° to25° to the occlusal plane.

Delaire 1971

Petit Face Mask 1983

The Petit facial mask was originally

constructed on a patient-by-patient

basis, using .25" round lengths of

stainless steel, to which pads for the

forehead and chin were attached

video

CLASS III CAMOUFLAGE TREATMENT

Treatment approach were the underlying skeletal

deformity is left untreated but teeth are moved to such

positions to create an acceptable occlusion with out

violating the norms of aesthetics and stability is

categorised as camouflage treatment.

Treatment approaches

2 Approaches.

NON EXTRACTION

EXTRACTION

NON EXTRACTION APPROACH

1.THE MEAW TECHNIQUE

INTRODUCED BY KIM IN 1987

IT S AN IDEAL EDGEWISE ARCH WIRE WITH ADDITION OF BOOT LOOPS.

THE VERTICAL LOOPS COMPONENT SERVES AS A BREAKBETWEEN THE TEETH,GIVES FLEXIBILITY TO THE ARCH WIRE,AND ALLOW HORIZONTAL CONTROL OF THE TOOTH POSITION

IT WAS ORIGINALLY PRESCRIBED FOR BRACKETS WITH 0.18 INCH SLOTS AND 0.16 X 0.022 INCH ARCH WIRE ALLOWING MORE FLEXIBILITY FOR INTRUSIVE FORCE.

USE OF DISTALIZATION OF LOWER ARCH USING

ANCHORAGE DERIVED FROM MINI IMPLANT

THE TADS HAVE PROVED USEFUL IN PROVIDING ANCHORAGE

REQUIRED TO DISTALIZE THE WHOLE MANDIBULAR ARCH

INCLUDING SECOND MOLAR.

THE PRESENCE OF THIRD MOLARWILL HAVE TO BE EVALUATED

AND IF NEEDED BE,IT MAY REQUIRE SURGICAL CORRECTION.

EXTRACTION APPROACH.

DEPENDING ON THE REQUIREMENT OF THE CASE

EXTRACTION CHOICES COULD BE.

MANDIBULAR INCISOR

UPPER SECOND AND LOWER FIRST BICUSPIDS

LOWER FIRST BICUSPIDS

MANDIBULAR SECOND MOLARS

MANDIBULAR INCISOR EXRACTION

SITUATIONS WHERE CROWDING IS NOT LARGE OR

SITUATIONS OF BOLTONS DICCREPANCY.

UPPER/LOWER MIDLINE MISMATCH

LONGTERM RIGID LINGUAL RETAINER AS MANDIBULAR

ARCH WITH THREE INCISORS HAS A TENDENCY FOR

LINGUAL COLLAPSE.

UPPER SECOND AND LOWER FIRST BICUSPIDS.

TO RESOLVE LARGE MANDIBULAR CROWDING,AND

INDUSE SIGNIFICANT TIPPING OF MANDIBULAR ARCH.

MAXILLARY ARCH WHICH HAS LESSER CROWDING,

CONSIDERD FOR SECOND PRE MOLAR EXTRACTION.

LOWER FIRST BICUSPIDS

WHEN UPPERARCH IS WELL ALIGNED OR CAN BE WELL ALIGNED WITH DENTAL EXPANSION OF THE ARHES.

LOWER ARCH NEEDS SPACE TO RESOLVE CROWDING AND

LINGUAL TIPPING OF MANDIBULAR INCISORS

MANDIBULAR SECOND MOLARS

FOR SIGNIFICANT DISTALIZATION OF ENTIRE LOWER

DENTAL ARCH

THE LOWER DENTAL ARCH CAN BE DISTALIZED EITHER

WITH CERVICAL HEADGEAR OR ANCHORAGE DERIVED

FROM INTRORAL IMPLANTS.

CONCLUSION

Early orthopedic treatment using face mask or chin cup

therapy improve skeletal relations which in turn minimizes

excessive dental de compensation.

Early treatment provides more pleasing facial profile,

thus improves psyco-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.

References

Contemporary orthodontics; william R. profit

Text of orthodontics, samier bishara

In clinical orthodontics, Ravindra nanda

Orthodontics current priciplesand techniques, T.M Graberand

vanarsdal

DENTOFACIAL ORTHOPEDICS WITH FUNCTIONAL APPLIANCES