青少年期不同垂直骨面型个别正常下颌骨形态及牙列特征研究

摘要

目的 探究不同垂直骨面型的青少年个别正常下颌骨形态及牙列特征,了解其正常范围及变化规律,为青少年期正畸患者的矫治提供一定参考.方法 选取42例个别正常的青少年(12～18岁)为研究对象,根据下颌平面角(FH/MP)分为低角组(7例),均角组(23例),高角组(12例).通过Invivo 5软件分别测量其平面角、L6牙长轴交角、∠L1/MP、∠L6/MP、Balkwill角、Bonwill三角高与底之比,以了解其颅颌面特征.结果 低角组的平面和L6牙长轴交角小于均角组和高角组;均角组的∠L1/MP大于高角组;高角组的∠L6/MP小于低角组和均角组,差异均具有统计学意义(P＜0.05);其余测量项目,差异无统计学意义(P＞0.05).结论 青少年不同垂直骨面型个别正常下颌骨形态及牙列特征间存在差异.低角组平面相对于均角组和高角组更加平行于眶耳平面;低角组下颌第一磨牙在颊舌方向上相对于另外两组直立,而在近远中向上,其牙长轴相对于下颌体近中倾斜更加明显.此测量结果与成年人群个别正常之间存在差异,提示随着年龄增长与颅颌部发育变化,与之相适应的功能也将发生改变.%Objective We aim to examine teenagers with varying vertical facial skeletal types with near-normal occlusion.We further aim to identify and study mandibular morphology and dentition characteristics to establish normal ranges and variations for future clinical reference.Methods According to the results of the case studies, 42 adolescents with near-normal occlusion were divided into three groups, namely, low- (7 cases), average- (23 cases) and high-angle (12 cases) groups.We used Invivo 5 software for Digital Imaging and Communications in Medicine (DICOM) data to calculate the cant of occlusal plane, axis corner of L6, ∠L1/MP, ∠L6/MP, Balkwill angle and Bonwill triangle of each group.Results Markedly, the finding shows that the cant of occlusal plane and axis corner of L6 in the low-angle group were smaller than those of the other two groups.In the average-angle group, ∠L1/MP was larger than that of the high-angle group.Lastly, in the high-angle group, ∠L6/MP was smaller than those of the two other groups.On the one hand, these differences were considered statistically significant (P＜0.05).On the other hand, other measurements show that these differences were considered statistically non-significant (P＞0.05).Conclusion In the low-angle group, the parallelisation of the occlusal plane tends to be more obvious compared with the two other groups.In the coronal section of the low-angle group, the axis of the mandibular first molar is up-right, whereas it is distally tilted in the sagittal section of the high-angle group.Furthermore, a number of differences are noted in the adult groups.Factors, such as aging and development in the craniofacial region, lead to changes in functional occlusion.