90例汉族年轻成人正常牙形态测量分析

目的: 对上海某高校90例汉族年轻成人正常牙形态进行三维测量,为开发适合中国人牙颌面特征的直丝弓矫治器提供数据参考。方法: 从上海某高校9000名大一新生中筛选出90名18~24岁正常汉族年轻成人,收集全口硅橡胶牙列印模,进行三维扫描,获得数字化牙列模型,用Smartee Ortho（A）三维测量软件测量,获得牙冠轴倾度、转矩角、唇（颊）侧冠凸距指标。采用SPSS 17.0软件包进行统计分析,得出测量结果均值。结果: 测量获得年轻成人正常牙冠轴倾度、转矩角、唇（颊）侧冠凸距均值。关于牙冠轴倾度,除上颌第二磨牙外,其余牙的牙冠均向近中倾斜,上、下前牙轴倾度普遍小于欧美人。关于牙冠转矩,上、下前牙转矩均大于欧美人,尤其是上、下尖牙更为唇倾;上、下后牙转矩小于欧美人,更舌向倾斜。关于牙冠凸距,上中、侧切牙间冠凸距差值小于欧美人,下颌尖牙与侧切牙、下颌第一与第二前磨牙间牙冠凸距大于欧美人。结论: 中国人正常牙冠轴倾度、转矩角、唇（颊）侧冠凸距指标与欧美人存在差异,有必要开发符合中国人牙颌面特征的直丝弓矫治器。

Measurement and analysis on the teeth morphology in 90 Chinese Han young adults with normal occlusion

PURPOSE: To measure and analyze the teeth surfaces in 90 Chinese Han young adults with normal occlusion from one university in Shanghai, and to provide data for straight wire appliance system for Chinese patients. METHODS: 90 volunteers with normal occlusion were selected from 9000 college freshmen in Shanghai,whose dental impression with normal occlusion were scanned into digital models. Crown angulation, crown inclination, buccal(labial) crown facial prominence were measured and analyzed by Smartee Ortho（A）software. SPSS 17.0 software package was used for statistical analysis. RESULTS: The mean values of the teeth surfaces in normal occlusion were obtained, including crown angulation, crown inclination, buccal (labial) crown facial prominence. Crown angulations were leaning toward the middle line except upper second molars. Compared with west Caucasian, angulations were smaller in incisors and canines, and crown inclinations were larger in incisors and canines, especially the upper and lower canines. The upper and lower molars were inclined more to the lingual side. Crown facial prominence differences between upper first and second incisor were smaller, while the differences were larger between lower second incisor and canine, lower first and second molar. CONCLUSIONS: There are differences between Chinese and west Caucasian with normal occlusion. It is necessary to invent a kind of straight wire appliance system for Chinese patients.