下颌后牙区骨内解剖结构的CBCT测量分析

目的:探讨口腔专用锥形束CT(CBCT)对下颌后牙区骨内三维结构、走行特点以及毗邻关系进行观察和测量的临床可行性,运用easydent计算机软件进行图像重建和分析测量,得出下颌管、颏孔的正常位置,为临床操作提供理论依据。方法:回顾性分析100例患者CBCT影像资料。测量20岁以上不同性别分组人群第一、二前磨牙及第一、二磨牙根尖处下颌管位置的4个距离:下颌管上缘到牙槽嵴顶(MA)、下颌管下缘到下颌骨下缘最下点(MD)、下颌管外缘到与颊侧在同一水平线的颊侧点(MB)、下颌管内缘到与舌侧在同一水平线的舌侧点(ML)的距离,每个距离测量3次,取其平均值,并观察不同性别分组人群颏孔位置。结果:不同性别分组人群后牙区下颌管至周围MA、MD、MB、ML4个距离差异均无统计学意义(P>0.05),颏孔位于第一前磨牙根尖区2例(1.0%),第一、二前磨牙之间80例(40.0%),第二前磨牙根尖区107例(53.5%),第二前磨牙和第一磨牙之间11例(5.5%)。结论:运用CBCT测量下颌后牙区骨内解剖结构,对临床操作中如进行正颌手术中下颌骨矢状劈开术(SSRO)、下颌骨囊肿刮治术、下颌骨种植术以及自体取骨术等有一定的临床指导意义。

Measurement and analysis of anatomical structure of bone in mandibular posterior area

Objective: To explore the feasibility of detecting 3D anatomical structure of bone and its adjacent tissues in mandibular posterior area with CBCT,and to identify the normal location of mandibular canal and mental foramen in order to provide a theoretical basis for clinical operations.Methods:Cone beam computed tomography(CBCT) image of 100 patients were selected and divided into different groups according to their gender.Length:(1)between the upper edge of mandibular canal and alveolar crest(MA),(2)between the lower edge of mandibular canal to lowest point of lower border of the mandible(MD),(3) between the outer edge of the mandibular canal to buccal point of the buccal at the same horizontal level(MB),(4) between the inner edge of mandibular canal to tongue inlingual points at the same horizontal level(ML) were measured and compared.Data were expressed as mean of three values.Location of mandibular canal in different gender was also observed.Results:No significant difference in MA,MD,MB and ML was observed between different groups.Mandibular canal located at apical area of the first premolar in 2 cases(1.0%),and located at the spaces between the first and second premolar in 80 cases(40.0%),located at apical area of the second premolar in 107 cases(53.5%),and at spaces between the second premolar and first molar in 11 cases(5.5%).Conclusions:Anatomical structure measured with cone-beam CT can provide guidance to surgeries like SSRO,scaling of cysts,implantation of self bone,etc.