Craniofacial Adaptations Induced by Class III Elastics-chincup Versus Chincup Therapy

Objective: The purpose of this study was to evaluate the different effects of two kinds of orthopedic force produced by Class III elastics-chincup and chincup therapy in skeletal Class III patients. Methods: 36 prepubertal patients with skeletal Class III malocclusion with anterior cross-bite were selected, and were randomly divided into two groups.18 patients were treated with Class III elastics at daytime and chincup therapy at night as experimental groups. The others, control group, were treated with chincup therapy only at night. The orthopedic force was approximately 400g and the force was passed through the center of the condylar process. All subjects had lateral cephalograms taken before treatment (T0) , after treatment (T1) and at retention (T2). Results:The treatment outcomes of the two groups showed a significant improvement of the skeletal Class III malocclusion; Cephalometric measurements showed significant differences in temporomandibular joint morphology between the two groups at T0 to T1 in the direction of the condylar head, width and depth of the glenoid fossa. Conclusions: This study indicated that the effects of using Class III elastics-chincup therapy was more effective than ones just using chincup at night; the continuous orthopedic force may be useful to the remodeling of condylar process for growing patients.