management of class ii and iii malocclusion

Management of Class II and Class III Malocclusion

What is Normal / Ideal / Gold Standard?• Dental Objectives:

• Ideal Overjet

• Ideal Overbite

• Co-incident midlines

• Class I Incisor and canine Relationship

• Fully intercuspated molar relationship Class I / II / III

• Tight contacts

• Complete leveling and alignment

• Functional Occlusion

What is Normal / Ideal / Gold Standard?

• Facial / Skeletal Objectives:• Well balanced facial profile i.e. straight faical profile

• Normal / near normal vertical facial dimensions

• Improved competency of lips

• Balanced lip profile i.e. no lip procumbency or recumbency

• Ideal incisal display on smile and at rest

• Ideal esthetic line / smile arc

• Normal TMJ function

Class I

Class II

Class II div 1

Class II div 2

Class II Subdivision

Class III

True Class IIIPseudo Class III

THREE CLASSES

Class III Subdivision

Class II malocclusion

• Dental Class II• Class II Division 1

• Class II Division 2

• Skeletal Class II

Management of Dental Class II Malocclusion

Division 1

Division 2

Class II Malocclsuion

Growing Patient

Skeletal Class II

Maxillary Prognathism

Headgear Treatment

Mandibular Retrognathism

Functional Appliances e.g. Activator,

Bionator, Twin Block, Frankel II

Dental Class II

Orthodontic Treatment

Adult

Patient

Skeletal Class II

Mild

Camoflague with Orthodontic Treatment

Extract upper 4s onlyExtract upper 4s lower

5s

Severe

OrthognathicSurgery

Maxillary setback,BSSO mandibular

advancement

Dental Class II

Orthodontic Treatment

Class II Division 1 Malocclusion


FEATURES

• Proclined upper incisors

• Increased overjet

• Class II canine and molar relationship

• Procumbent upper lip

• Convex facial profile

• Acute nasolabial angle

TREATMENT OBJECTIVE

• Retract upper incisors and correct their inclination

• Achieve ideal overjet and overbite

• Achieve Class I incisor and canine relationship

• Improve upper lip procumbency

• Improve nasolabial angle

Treatment Objective Treatment Approach

Retract upper incisors and

correct their inclination

If spaces present, close them.

If no spaces present consider extraction of upper 1st premolars and use

their space to retract incisors.

Achieve ideal overjet and

overbite

Correct deepbite early in treatment.

Maintain deepbite correction while retracting incisors

Achieve Class I incisor, canine

and molar relationships

Use Class II elastics as required

Improve nasolabial angle Ensure maximum retraction of upper incisors, upper lip will follow teeth.

Upper anchorage is critical in Class II treatment

Improve upper lip procumbency Retract upper incisors.

May require extraction of lower premolars, so upper incisors can be

retracted after the retraction of lower incisiors.


Suggested Extraction Patterns

• Distalize upper whole arch without any extraction

• Extract upper first premolars only

• Extract upper second premolars only

• Extract upper first and lower second premolars

• Can extract upper first premolars and one lower incisor

Camouflage

Effect of functional appliances

CLASS III MALOCCLUSION

INTRODUCTION

Edward Angle classified malocclusion in 1899 based on anteroposterior relationship of the jaws with each other as –

CLASS I CLASS II CLASS III23

CLASS III MALOCCLUSION

Prenormal occlusion or mesioclusion

‘Mesial’ or ‘ventral’ relationship of maxilla to mandible

The mesial groove of mandibular first permanent molar articulates anteriorly to the mesiobuccal cusp of maxillary first permanent molar

Introduction…

1.True or skeletal class III

• mandibular hypertrophy

• Marked shortening of midface

• combination

Handbook of orthodontics by Robert Moyers; 4th edition25

A] Angle classified –

CLASSIFICATION

2. Pseudo or functional or postural class III

• Occlusal prematurities

• Premature loss of deciduous posteriors

• Enlarged adenoids

3. Class III , Subdivision

• Class III on one side and class I on other

Handbook of orthodontics by Robert Moyers; 4th edition26

Classification…

CLINICAL FEATURES

A] Extraoral features :

1. Concave profile

2. Anterior facial divergence

3. Retrusive nasomaxillary area

4. Prominent lower third of face/chin

5. Steep mandibular plane angle

27

B] Intraoral features :

1. Class III molar and canine

relationship

2. Narrow upper arch

3. Decreased or reverse overjet

4. Crowding in upper arch and

spaced lower arch

28

Profile Assessment :

1. Facial proportions

- Straight, convex or concave

- Maxillary deficiency shows

concave profile, flattening of

infraorbital rim

29

2. Chin position

- Chin should not be positioned

anterior to a vertical line extending

down from soft tissue glabella

- Facial convexity decrease with age

30

3. Mid-face position

- an imaginary line extending from

inferior

border of the orbit through the alar

base of

nose and down the corner of mouth

- A straight or concave tissue contour

indicates midface deficiency

31

4. Vertical proportions

- Checked in CO and CR

- Normal ratio for lower facial height to total facial

height is 0.55

- Decreased in patients with functional shift and

overclosure of mandible

32

2. Study models

33

Diagnosis…

3. Radiographs

34

Pantomogram (OPG)

Lateral cephalogram

Diagnosis…

4. Cephalometric analysis

The SNA angle is significantly

lower

Negative ANB angle

Greater mandibular protrusion

Increased gonial angle

(more obtuse)

Steep mandibular plane angle

Increased lower facial height

35

Diagnosis…

DIFFERENTIATING A DENTAL CROSSBITE FROM A SKELETAL CROSSBITE

36

DENTAL ASSESMENT

(Molar relationship and overjet)

Class III molar relationship

Positive overjet or end-to-end incisal relationship with

retroclined mandibular incisors

Class III molar relationship

Negative Overjet

FUNCTIONAL ASSESMENT

Compensated Class III malocclusion

Pseudo Class III malocclusion

True Class III malocclusion

CR-CO ShiftNo CR-CO Shift

Textbook of orthodontics by Dr. Samir Bishara

Diagnosis…

TREATMENT OF PSEUDO CLASS III

Removal of CO-CR discrepancy – avoid normal wear and

traumatic occlusal forces to affect the teeth

Removes potential adverse effects on growth of jaws

Establishes good functional occlusal

Improves facial aesthetics

37

Correction of anterior crossbite :

38

Tongue blade Anterior inclined plane

Z-spring

Treatment…

Correction of posterior crossbite:

39

Removable expansion plate

Fixed expansion appliance

Treatment…

Correction of occlusal prematurities :

40

Occlusal splint

Treatment…

TREATMENT OF TRUE CLASS III

Why should the treatment be started early ?

Facilitates the eruption of canines and premolars in a normal relation

Eliminates the traumatic occlusion of incisors

Provides an adequate maxillary growth

Improves the self esteem of the child

41

42

According to Turpin et al (1981) –

- Good facial aesthetics

- Mild skeletal disharmony

- No familial prognathism

- Anteroposterior functional shift

- Convergent facial type

- Symmetric condylar growth

- Growing patients

- Expected good cooperation

- Poor facial aesthetics

- Severe skeletal disharmony

- Familial pattern established

- No Anteroposterior shift

- Divergent facial type

- Asymmetric growth

- Non-growing patients

- Expected poor cooperation

EARLY TREATMENT

TREATMENT DELAYED


Treatment…

43

TREATMENT PROTOCOL

GROWING PATIENTS

SKELETAL DENTAL

NONGROWING PATIENTS

DENTAL SKELETAL

Orthopedic / myofunctional

appliances

Orthognathic surgery

Orthodontic treatment as

needed

Treatment…

1. REVERSE ACTIVATOR

44

Treatment…

*Removable orthodontic appliances by Graber and Neuman: 2nd Edition

2. BIONATOR

45*Removable orthodontic appliances by Graber and Neuman: 2nd Edition

Treatment…

3. REVERSE TWIN BLOCK

46

Treatment…

4. FRANKEL III REGULATOR (FR III)

More successful in patients with functional shift on closure

Increased overbite of 4-5 mm

Early mixed dentition

Also, as a retentive device after maxillary protraction

47Textbook of orthodontics by Dr. Samir Bishara

Treatment…

1. FACE MASK

Used in patients with mild to

moderate Class III with maxillary

retrusion

2 pads connecting soft tissue in

forehead and chin region

48

ORTHOPAEDIC APPLIANCES

Treatment…


Design and construction :

- 2 pads connecting soft tissues in forehead and chin region with a metallic framework

- Elastics attached near the maxillary canine region with a downward and forward pull of 300 to the occlusal plane

- Metallic banded or acrylic bonded palatal expansion plate can be attached

49

Treatment…


Force magnitude and direction:

- Orthopedic force of 300-600 g/side

- 10-12 hours/day

- Force directed 5mm above the palatal plane

- 30 to 450 protraction force applied at maxillary canine region

Treatment timing:

- Primary or early mixed dentition period

- Mostly at the time of initial eruption of maxillary centrals

- Duration may vary from 3-16 months50

Treatment…


2. CHIN CUP

Used in skeletal Class III malocclusion with a relative normal maxilla and a moderately protrusive mandible

Two types:- Occipital pull- Vertical pull


Treatment…

Effects on growth:

A) Mandible- Redirection of mandibular growth vertically

- Backward repositioning or rotation

- Remodeling with closure of gonial angle

- Posterior movement of Point B and Pogonion


Treatment…

Force magnitude and direction:

- Orthopedic force of 300-500 g per side

- 14 hours/day

- Directed usually through condyle or below the condyle

Treatment timing:

- Primary or early mixed dentition

- Treatment time varies from 1 year to 4 year depending on severity


Treatment…

ORTHODONTIC CAMOFLAGE

Indications :

Skeletal discrepancies not resolved during mixed dentition

Malocclusions recurring during adolescence after treatment in childhood

Mild mandibular prognathism and moderate crowding

Types :

With extractions

Without extractions

54

Treatment…


Depending on the malocclusion extraction can be done as follows:

Two lower premolars or a mandibular incisor

All four premolars

Maxillary 2nd and mandibular 1st premolars

Mandibular second molars


Treatment…

Class III elastics :

From upper molar to lower anteriors

Corrects molar relation by moving the molar mesially

Retraction of lower anteriors


ORTHOGNATHIC SURGERY

Indications :Continued disproportionate sagittal and vertical growth

Severe skeletal maxillary retrusion and mandibular prognathism or both

Non-growing patients

Cleft lip and palate

Facial asymmetries

57

Treatment…

Mandibular prognathism :

1. Mandibular ramus osteotomy

(BSSO)

2. Mandibular inferior body

osteotomy


Treatment…

Maxillary retrusion :

Le Fort I osteotomy with maxillary advancement


Treatment…

THANK YOU

60

management of class ii and iii malocclusion

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