本研究纵向观察了121名受试者乳牙到恒牙磨牙关系的变化,讨论这些变化与正常的牙齿、牙列、颅面部变化之间的关系。 121名受试者中男性为60名,女性61名,是从3.5岁～12岁受试者两年进行一次,17岁以前一年进行一次的模型纪录和X线头影测量中筛选出来的。受试者无先天性缺牙;无第一二乳磨牙早失,未有接受正畸治疗病史。作者分别记录了完全乳牙 In this study, we observed the changes of the molars between permanent dentition and molar teeth in 121 subjects, and discussed the relationship between these changes and the changes of normal teeth, dentition and craniofacial regions. Of the 121 subjects, 60 were males and 61 were females, screened from a model record of two years from 3.5 to 12 years of age, one year prior to age 17, and X-cephalometry. Subjects without congenital edentulous; no first two molars lost early, did not accept the history of orthodontic treatment. The authors recorded complete deciduous teeth respectively