安氏Ⅱ类亚类错畸形一直以来都是临床治疗中的重点、难点,而治疗时机的选择往往会影响到矫治的最终效果。本研究利用锥形束CT(cone-beam computerized tomography,CBCT)技术,对不同年龄段安氏Ⅱ类亚类错患者的上下牙弓、下颌骨的对称性进行比较研究,旨在为临床治疗的时机选择提供参考。一、材料与方法 Class Ⅱ subclass malformations deformity has always been the focus of clinical treatment, the difficulty, and the timing of treatment options will often affect the ultimate effect of orthodontic treatment. In this study, the cone-beam computerized tomography (CBCT) technique was used to compare the symmetry of the upper and lower dental arch and mandible in patients with Class Ⅱclass malocclusion in different age groups. The timing of choice for reference. First, materials and methods