目的探讨安氏(Angle)Ⅱ类1分类错牙合畸形患者矫治前拔牙与否的形态学差异。方法选择临床获得满意疗效的恒牙早期120例AngleⅡ类1分类错牙合畸形的患者,其中未拔牙组42例,拔牙组78例,对其矫治前的X线头颅侧位定位片进行软硬组织和牙(牙合)模型的回顾性比较研究。结果两组矫治前形态学上的差异主要表现在:①硬组织:SNB、ANB、NA-PA、Npg-FH、Go-Pog、Ptm-s、FMIA、U1-L1、U1-Apgmm。②软组织:上唇厚度、下唇长度、颏唇沟厚度。③牙(牙合)模型:上下颌拥挤度、Spee氏曲线曲度、覆盖、上颌中后段宽、下颌中后段宽、上颌中段长。结论下颌的后缩程度、上前牙的突度、上唇厚度及牙列的拥挤度是决定拔牙与否的重要因素。 Objective To investigate the morphological differences of Angle Ⅱ class 1 malocclusion patients before and after tooth extraction. Methods One hundred and twenty patients with Angle Ⅱ class 1 malocclusion in the early stage of permanent dentition with satisfactory curative effect were selected. Among them, there were 42 cases without extraction group and 78 cases with tooth extraction group. The X - A retrospective comparative study of tissue and dental occlusion models. Results The morphological differences between the two groups were mainly as follows: ① Hard tissues: SNB, ANB, NA-PA, Npg-FH, Go-Pog, Ptm-s, FMIA, U1-L1 and U1-Apgmm. ② soft tissue: upper lip thickness, lower lip length, chin lip groove thickness. ③ teeth (occlusal) model: crowding of the mandibular crowding, Spee curve curvature, covering the upper jaw in the wide section, the middle and wide section of the mandible, the middle of the long jaw. Conclusions The degree of mandibular retraction, the protrusion of the anterior teeth, the thickness of the upper lip and the crowding degree of the dentition are the important factors that determine the extraction of teeth.