阻生下颌第二磨牙下颌骨的三维分析

Three-dimensional analysis of the mandible with impacted mandibular second molar

目的研究阻生下颌第二磨牙患者下颌骨的发育和形态特征,并且通过三维测量和分析预测下颌发育的可能趋势。方法筛选出阻生组和对照组各88例,利用Mimics软件建模进行三维测量,共确定了23个标记点和17个测量值,对测量值进行t检验分析。结果阻生组中下颌体长度、第一磨牙后萌出间隙、下颌角间距和第一磨牙间宽的值低于对照组(P<0.05),颌下角的值高于对照组(P<0.05)。结论本研究发现下颌第二磨牙阻生患者的下颌骨呈现出在矢状向和宽度上的发育不足,下颌第二磨牙阻生是其退化的表现之一。

Objective To study the developmental and morphological characteristics of the mandible in patients with impacted mandibular second molar and to predict the possible trend of mandibular development via three-dimensional(3D)measurement and analysis.Methods A total of 88 cases of impacted group and 88 cases of control group were screened out.3D measurements were performed by using Mimics software.A total of 23 landmark points and 17 measurements were determined.The measurements were analyzed by t-test.Results The mandible length,the space between the first molars,the space between mandibular angles,and the width between the first molars in the impacted group were lower than those in the control group(P<0.05).Moreover,the value of the submandibular angle was higher than that in the control group(P<0.05).Conclusion The impacted mandible of patients with mandibular second molar showed lack of sagittal and width development,and the impacted mandibular second molar was a manifestation of its degeneration.