Temporomandibular Joint Growth Changes in Herbst Treatment

Objective To study the effects of Herbst appliance on temporomandibullar joint (TMJ) of patients with ClassⅡ, Division Ⅰ malocclusion. Methods Eighteen Class Ⅱ, DivisionⅠmalocclusions were treated with the Herbst appliance, the amount and direction of condylar growth, glenoid fossa displacement and TMJ changes were analyzed with cephalometrics. Reasults It revealed that during the treatment period (T2-T1) condylar growth was directed posteriorly about twice the amount as in the control subjects, and the fossa was displaced in an anterior inferior direction. TMJ changes showed a pattern similar to condylar growth but were more pronounced. During the first posttreatment period (T3-T2), all TMJ changes reverted. The glenoid fossa was displaced backward; the amount of condylar grows and TMJ changes was reduced, and the changes were more superiorly directed. During the second posttreatment period (T4-T3), all TMJ changes were considered physiological. Conclusion During Herbst treatment, the amount and direction of TMJ changes (condylar growth, fossa displacement, and TMJ changes) were only temporarily affected favorably by Herbst treatment. [