Abstract: Objective To analyze the correlation between patients′bone age and morphology change of their mandibular bone when treated with Dynamax or TBA. Methods 15 patients selected for each group were treated with new Dynamax or TBA for 9 months.After removing the appliances,we observed for 3 months and then conducted cephalometric analysis of each patient. Results There were significant differences in the Co-Gn,Co-Go,Go-Gn between the two treatment groups and the control group (P<0.05).There was strong correlation between patients′bone age and morphology change of the mandibular bone when treated with Dynamax or TBA(P<0.05),but not in control group. Conclusions The Dynamax could make mandibular circumrotate backward,and promote the condyle growth both vertically and sagittallyin treatment of the Class Ⅱ division 1 patients.And there is correlation between bone age changes and the vertical and sagittal growth of the mandible.The TBA makes the mandible grow vertically.And there is correlation between bone age changes and the vertical growth.

Key words: class Ⅱ division 1 malocclusion, functional appliances, bone age, correlation analysis, cephalometrics