上海地区恒牙早期正常人群分类模板图的初步研究

The preliminary study on creating the differential templates of the skeletal profiles for Shanghainese with normal occlusion in early permanent dentition

目的 探讨上海地区恒牙早期正常人群硬组织侧貌分类模板图的研究方法 ,将分类模板法引入正常研究。方法 将 71例 11岁～ 14岁正常人的头影侧位定位片轮廓图输入计算机 ,将 2 3个标志点矢量化 ,使图形简化为线条图。对图形作Steiner分析并进行男女样本t检验 ,计算图形的长 /深比。结果 两类样本差异无显著性 ,合并计算长 /深比的均值、标准差 ,分别为 1 42 36和0 0 819,据此将图形分为 3类 ,分别重叠得到侧貌形态短深、均匀、瘦长 3类模板图。结论 将 3类模板图重叠后 ,三者有明显差异。

Objective To establish the differential templates of the skeletal profiles for Shanghainese with normal occlusion in early permanent dentition. Methods 71 lateral cephalometric radiographs of subjects with normal occlusion in early permanent dentition, aged from 11～15 years (37 females and 34 males) were traced. 23 skeletal landmarks were identified on the tracings, which afterwards were scanned on the computer. An x y coordinate system was established: the tracing superimposed on sella rotated 7 degrees down from the sella nasion line as the x axis and the vertical line through sella perpendicular to the x axis as the y axis. A special length/depth ratio was designed.The length/depth ratio of each graph were caculated. Steiner analysis was applied to check the difference between genders. Results There was no difference between genders.The tracings were divided into three categories: short face, normal face and long face according to the mean and standard deviation of the ratio. The three types of tracings were superimposed on the x axis with sella registered. Three templates were created. Conclusions The differences were apparent when the three templates were superimposed.