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Class II Minimum-Touch Approach in an Evolving Orthodontic World Luis Carriere. AAO June 2021. Episode 115

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Farooq Ahmed

Class II Minimum-Touch Approach in an Evolving Orthodontic World Luis Carriere

 

Objectives of class 2 mixed dentition

·      Mandible moved forwards

·      Decrease the projection of the maxilla  – to shorten and curl the upper lip

·      Improve structures of TMJ

 

Carriere appliance

·      Rigid appliance on 3-6

·      Rubber bands

·      Change the occlusal plane to maximise projection of mandible

·      Joint on 6 to rotate the molar

·      Lower arch – VFR with bracket on L6

·      Class 2 elastic from U3-L6

 

Advantage

·      Segmentation of arch

o   Freedom of the arch to move for AP correction

§  Independent RHS and LHS, can overcorrect

·      Patient comfort high compared to Forsus appliance

·      Self limiting for molar rotation correction

o   Deliver rotation necessary, not any greater as self collision points built into the appliance

o   87% of class 2 molars require rotation Henry 1956

o   Molar rotation: if upper molars rotate mesially = more class 2, distal rotation class 2Arnald 1954

 

Mixed dentition challenges

·      Occlusal cusps shallow = poor intercuspation

o   Solution = overcorrection to allow for AP relapse

 

 

Changes with Carriere appliance

·      Upper lip length reduces – as the protrusive upper incisors elongate the upper lip

o   Upper lip curls and shortens

·      Improve Wits appraisal Kim-Berman – 2019

·      Clockwise rotation occlusal plane

o   Sounds contradictory

§  However in class 2 condyle is posteriorly seated Gokalp 2016 and the disc is anterior, Carriere appliance allows distraction of the condyle – releasing the space at the condyle, therefore the disc repositions anteriorly

§   Airway improvement – further studies required

§  Preserve maxillary volume – posterior dental repositioning, no archlength reduction

 

Adult patient

·      Severe class 2 + TMD

·      Orthognathic surgery is an option however there will be no correction of the TMD

o   Condyle is distal in position and impinging on the retro-discal ligaments

·      If condyle moves forwards

o   Elastic recovery of TMJ ligaments aids distraction and permanent repositioning of the mandible anteriorly

o   TMD resolved as posterior disc no longer impinged and reposition of mandible anteriorly, no change in growth

·      Limited evidence on Carriere appliance resulting in condylar changes

 

 

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