Objective      To analyze the morphological characters of mandible and temporomandibular joint in mandibular asymmetry patients with class Ⅱ subdivision malocclusion before and after orthodontic treatment by cone-beam computed tomography (CBCT).       Methods      For 60 mandibular asymmetry patients with class Ⅱ subdivision malocclusion

who were at the pubertal stage or after the pubertal stage

CT images were reconstructed into 3D models by Mimics 15.0 and 3D coordinate system was set up. Anatomical landmarks of mandible

condyle and glenoid fossa were located and established reference planes. Eleven sets of measurements from anatomical landmarks of mandible

condyle and glenoid fossa were used for statistical analysis.       Results      The morphology of mandible

condyle and glenoid fossa at class Ⅰ side and class Ⅱ side in mandibular asymmetry patients with class Ⅱ subdivision malocclusions at the pubertal stage had no difference before and after orthodontic treatment. The length of mandibular rumus

condylar height and anterior fossa width at class Ⅰ side of patients after the pubertal stage were significantly larger than those at class Ⅱ side before orthodontic treatment (P0.05). But after treatment

only the anterior fossa width at class Ⅰ side was longer than that at class Ⅱ side (P=0.023).       Conclusion      Mandibular asymmetry of patients with class Ⅱ subdivision malocclusions is developed from functional mandibular deviation to skeletal deviation

and treatment at the pubertal stage is beneficial to reduce the deformity at the late stage.