Prediction of outcome of malocclusion class III after combined maxillary protraction and chin cup aplliance treatment

AIM:To investigate the differences in the skeletal morphology between the effective and the ineffective groups treated with same method .METHODS:32 female cases with malocclusion class Ⅲ were chosen and treated by combined protraction and chin cup divided into two groups(the effective and the ineffective group)according to the different treatment results. The cephalograms were taken at the beginning (T1) and after the treatment (T2) .Then the skeletal difference between the two groups was analyzed. RESULTS:At T1,the lower facial height inclination of mandibular plane and gonial angle were larger at the ineffective group.SNA was smaller in the effective group.At T2,the difference between facial height were increased.SNB was difference between two groups.From T1-T2,the effective group express more madibullar anterior displacement. CONCLUSION:Those results indicated that the vertical dimention of the craniofacial skeletal are important for prediction in the treatment of class Ⅲ malocclusion.