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Management of Class III malocclusion

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Dr Gazanafer Roshan

Department of Orthodontics, MES Dental College

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Contents

  • Introduction

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  • Etiology

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  • Classification

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  • Diagnostic consideration

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  • Management of Class 3 malocclusion

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According to Angle a Class III molar

relationship refers to a condition where

the mesio buccal cusp of permanent

maxillary first molar occluding in the

interdental space between the mandibular

first and second molars.

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Etiology

  • Heredity

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  • Functional factor and soft tissue

- Tongue posture

- Enlarged tonsils and naso respiratory

difficulties

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  • Pre mature loss of deciduous molars

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  • Cleft lip and palate

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  • Compulsive habits of protruding the mandible

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  • Trauma to the mid face during growth phase

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Classification

1. True Class III- Skeletal

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2. Pseudo or Postural or Habitual class III

-forward movement of the mandible during jaw closure

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3. Class III subdivision – Class III molar

relation on one side and Class I relation

on other side

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Clinical Features

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  • -Straight to concave

profile

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  • Anterior facial

divergence

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  • Class 3 molar relationship

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  • Incisors- edge to edge or an anterior crossbite

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  • Upper arch is frequently narrow and short and lower arch is broad

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  • Posterior crossbite

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  • Upper arch - crowded & lower arch - spacing

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  • Vertical growers – anterior open bite

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  • Presence of occlusal pre maturities resulting in habitual forward positioning of the mandible- Pseudo class 3

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  • Psedo class 3- rest position class 1 & centric relation class 3

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  • Skelatal features

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  • Maxillary retrognathism

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  • Mandibular prognathism

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  • Combination of both

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Diagnostic consideration

  • Clinical examination

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  • Radiographic examination

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  • Cephalometric analysis

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  • Study model analysis

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  • Soft tissue examination

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Growing Pt

Skeletal class III

Dental class III

Dental class III

Skeletal class III

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Max retrognathism & Mand prognathism

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Mild to mod class III

Severe class III

Mand prognathism

Max retrognathism

Max Retrogn

Max Advancnmt

Camouflage

Face mask followed by chin cap / myofunct. appl

Chin cap to retrict mand growth

Facemask to protract maxilla

Mand Prog

Non growing Pt

Mand set back

Ortho Rx

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Treatment

  • Should be recognized & treated early

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  • Recognizing at early age helps to intercept the abnormal skeletal pattern reduces the severity of developing malocclusion

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  • Class 3 with anterior crossbite retarded maxillary growth due to locking of maxilla within the mandible

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  • Occlusal force on mand.incisor by max incisors forward growth of mandible

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  • Interception during growth
  • Myofuntional appliance – Frankel III

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  • Chin cup therapy – used in protrusive mandible and normal maxilla

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  • Two types- occipital pull & vertical pull

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  • Backward repositioning of mandible, redirect the mandibular growth

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  • Facemask therapy

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  • Used in retrognathic maxilla

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  • Produces forward and downward movement of maxilla

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  • 300-500 gm / side

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  • 12-14 hours per day

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  • Treatment of anterior crossbite

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  • lower anterior inclined planes
  • Appliances incoporating screws for anterior expansion

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  • Treatment of posterior crossbite

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  • Rapid maxillary expansion

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  • Role of extraction

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  • Lower 4’s
  • Severe discrepancy in upper - all 4’s

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  • Treatment of severe class 3 after growth

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  • Maxillary retrognathism- lefort 1 advancement
  • Mandibular prognathism- BSSO set back

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  • Treatment of psedo class 3- removal of cause

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Pseudo class 3

  • Presence of occlusal prematurities

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habitual forward positioning of mandible

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  • Forward path of closure

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  • Profile straight most cases,

tends to become concave as mandible shifts to forward occlusal position

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  • anterioposterior relation is often class 1 or mild class III

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  • Pseudo class 3- maxillary incisors retroclined and mand. incisor upright

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  • True class 3- maxillary incisor proclined and mand incisor retroclined ( dento alveolar decompensation

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True class 3

  • Class 3 skeletal pattern

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  • Concave profile

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  • Etiology- hereditary

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  • Absence of premature contact

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Pseudo class 3

  • Usually class 1 or mild Class 3 skeletal pattern

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  • Straight/mild concave

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  • Etiology- functional,habitual, certain dental or skelatal

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  • Absence of premature contact

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