Objective To evaluate the effects of orthodontic treatment on the condylar and mandibular positions of patients with class Ⅲ malocclusion in mixed dentition. Methods 32 patients with Angle class Ⅲ malocclusions in mixed dentition were chosen. They were treated with maxillary protraction and straight wire technique. Lateral cephalometric films were taken individually before and after treatment, and linear measurement were observed. Statistical analysis was performed using SPSS 16.0 software package. Results Cephalometric radiography: After treatment, SNA, ANS-Ptm, Co-y, Ar-y, Go-y, NSAr, NSGo, NSPog, ArGo’-SN, Y axia, facial angle, ANB, Wits, NA-PA were increased significantly. Co-x, Pog-y, SNB, NP-FH, AB plane angle were decreased significantly （P<0.05）. And Ar-y, Go-y, Pog-y change in value before and after correction of the order increases, NSAr, NSGo, NSPog changes in the value of the order also increased. Conclusion A significant backward upward shift of condylar point, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed, which contribute to the correction of a skeletal class Ⅲ relationship.
