Huang Yi, Yan Yinqiu, Cao Jing, Xie Bingjie, Xiao Xueling, Luo Mengqi, Bai Ding, Han Xianglong
State Key Laboratory of Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, China.
Department of Orthodontics, West China School of Stomatology, Sichuan University, 14# 3rd Section, Ren-Min-Nan Road, Chengdu, 610041, China.
J Orofac Orthop. 2017 Nov;78(6):504-510. doi: 10.1007/s00056-017-0109-x. Epub 2017 Oct 27.
This study was designed to examine the relationship between third molar agenesis and skeletal morphology in the Chinese population.
A total of 1043 patients' records were analyzed with panoramic radiographs and cephalograms. Congenitally missing third molars were assessed with respect to gender, jaw, and side, and assessed in various types of facial morphology. Linear, angular, and proportional cephalometric measurements were analyzed and compared among the samples. For the evaluation of results, the following statistics were used: the Pearson χ test, one-way ANOVA, and the Student-Newman-Keuls method.
The overall prevalence of third molar agenesis was 28.7%. Missing third molars were more common in the maxilla and on the right side, while the difference was not statistically significant (P > 0.05) between genders. Every hypodontia group had a smaller SN-GoGn angle, Y-axis-FH angle, and a larger S-Go/N-Me ratio. The group with third molar agenesis in both jaws had smaller SNA and Wits values. The frequency of third molar agenesis in subjects with a Class II malocclusion was significantly lower than in other types of malocclusion (P < 0.05), and the incidence of third molar agenesis in hypodivergent growth pattern was higher than in other patterns (P < 0.05).
The results demonstrate a possible association between third molar agenesis and both sagittal and vertical craniofacial morphology.
本研究旨在探讨中国人群中第三磨牙缺失与骨骼形态之间的关系。
共分析了1043例患者的全景X线片和头影测量片。对先天性缺失的第三磨牙按性别、颌骨和侧别进行评估，并在各种面部形态类型中进行评估。对样本进行线性、角度和比例头影测量分析并比较。为评估结果，采用了以下统计学方法：Pearson χ检验、单因素方差分析和Student-Newman-Keuls法。
第三磨牙缺失的总体患病率为28.7%。上颌和右侧第三磨牙缺失更为常见，而性别之间的差异无统计学意义（P>0.05）。每个牙列缺损组的SN-GoGn角、Y轴-FH角较小，S-Go/N-Me比值较大。双侧第三磨牙缺失组的SNA和Wits值较小。安氏II类错牙合患者中第三磨牙缺失的频率显著低于其他类型的错牙合（P<0.05），低角型生长模式患者中第三磨牙缺失的发生率高于其他模式（P<0.05）。
结果表明第三磨牙缺失与矢状和垂直颅面形态之间可能存在关联。
