Abstract: Objective    To conduct a systematic review of anatomical studies based on cone beam computed tomography（CBCT）images to assess the mandibular canal variation and its anatomical incidence. Methods    The PubMed，Cochrane，and CNKI databases were searched for articles on the anatomical variation of the mandibular canal in adults from January 2005 to April 2019，and random effects models were used to analyze them. Through systematic reviews of the mandibles such as accessory mental foramen（AMF），retromolar foramen（RMF），mandibular lingual foramina（MLF），and bifid mandibular canal（BMC），the incidence of canal anatomical variation was analyzed. Results    Sixteen descriptive cross-sectional studies were finally included. The analysis results showed that the incidence of AMF was 9.54%（95%CI：6.39% - 12.69%）and the incidence of RMF was 23.64%（95%CI：14.44% - 32.84%）. MLF was found in every individual in the adult population studied，with the incidence of BMC being about 38.0%. Conclusion    The holes and tubes of the branches of the mandibular canal have great anatomical variation among individuals. The study of the anatomical variation of the mandibular canal based on CBCT images can provide clinical guidance.

Key words: cone beam computed tomography, CBCT；systematic review；Meta analysis；mandibular canal；anatomical variation

摘要： 目的    基于锥形束CT（cone beam computed tomography，CBCT）影像进行解剖学研究的系统评价，以评估下颌管变异及其解剖学发生率。方法    在PubMed、Cochrane、CNKI数据库中搜索2005年1月至2019年12月关于成年人群下颌管解剖变异的相关文章，并采用随机效应模型对其进行分析。通过系统评价对副颏孔（accessory mental foramen，AMF）、磨牙后孔（retromolar foramen，RMF）、下颌骨舌侧孔（mandibular lingual foramina，MLF）、下颌管分支（bifid mandibular canal，BMC）等下颌管解剖变异的发生率进行分析。结果    最终纳入16篇描述性横断面研究。分析结果显示，AMF发生率为9.54%（95%CI：6.39% ~ 12.69%），RMF发生率为23.64%（95%CI：14.44% ~ 32.84%），MLF在研究的成年人群中每一个体几乎均有发现，BMC发生率约为38.0%。结论    下颌管分支的各孔和管在个体间存在着较大的解剖变异，基于CBCT影像对下颌管解剖变异研究可为临床提供指导性意见。

关键词: 锥形束CT, 系统评价, Meta分析, 下颌管, 解剖变异