Abstract:

Objective To determine the longitudinal growth changes of mandible from mixed dentition to permanent dentition on Angle Class Ⅱ division 2 malocclusion. Methods The sample consisted of 95 students with Angle Class Ⅱ division 2 malocclusion and 75 students with normal occlusion. Cephalometric radiographs and hand-wrist radiographs were obtained for all the samples. And analysis of all the cephalograms was carried out. Results The study of growth changes of mandible from mixed dentition to permanent dentition showed that: 1）angle: The control group showed an increase in SNB and S-Ba-Go and a decrease in Ar-Go-Me, SN-MP and NSGn. In the experimental group, the changes in SNB, Ar-Go-Me, Cd-Go-Me, SN-MP, S-Ar-Go, S-Ba-Go were not of statistical significance, however, Y angle and NSGn were increased. In the control group, there was no statistically significant change in the Y angle. 2）chin: In the experimental group, chin concavity increased. The changes were not statistically significant for the other index. In the control group, chin curvature decreased. The chin height, chin depth, chin concavity, chin depth/chin height, SL and Pog to NB increased. 3）spacing: The growth of Cd-Go, Gn-Cd, Go-Me, Ar-Pog, Ar-Go in the control group was more than that of the experimental group. Conclusion The present finding will help the clinicians to come to a diagnosis and reasonable treatment plan in Angle Class Ⅱ division 2 patients.

Key words: Angle Class Ⅱ division 2, mandible, malocclusion