State Key Laboratory of Oral Diseases, Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China (mainland).
State Key Laboratory of Oral Diseases, Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China (mainland).
Med Sci Monit. 2018 Jan 2;24:26-36. doi: 10.12659/msm.905475.
BACKGROUND The objective of this study was to analyze the factors that can increase the possibility of mandibular canal (MC) defect in Chinese people, to evaluate the risk of nerve impairment, and to choose the proper operative method to reduce the risk of mandibular alveolar nerve injury during the extraction of mandibular third molar (MTM). MATERIAL AND METHODS A total of 954 patients (1,304 MTMs) who underwent orthopantomography (OPG) and cone-beam computed tomography (CBCT) between July 2014 and December 2014 were included in this study. The age and gender of patients, impacted type (high impaction, moderate impaction, and low impaction), Winter classification of MTM, position of MTM relative to MC, vertical classification of MTM and MC, and the feature images of OPG were collected and compared to the imperfection of the MC wall in CBCT images. RESULTS The wall situation of MC was significantly correlated with the age of the patient, the depth of the molar, the position of the roots, and six imaging appearances on OPG. There was no significant difference based on gender. CONCLUSIONS Most incomplete walls of MCs could be inferred by OPG. However, images based on CBCT could clarify the defect of the MC and also could clearly display the spatial relationship between the root and inferior alveolar canal.
本研究旨在分析增加中国人下颌管（MC）缺损可能性的因素，评估神经损伤风险，并选择合适的手术方法，以降低下颌第三磨牙（MTM）拔除过程中下颌牙槽神经损伤的风险。
共纳入 954 名（1304 颗 MTM）于 2014 年 7 月至 2014 年 12 月期间接受全景片（OPG）和锥形束 CT（CBCT）检查的患者。收集并比较患者的年龄和性别、阻生类型（高位、中位、低位阻生）、MTM 的 Winter 分类、MTM 相对于 MC 的位置、MTM 和 MC 的垂直分类，以及 OPG 的特征图像，与 CBCT 图像中 MC 壁的不完整情况。
MC 的壁情况与患者的年龄、磨牙深度、根的位置以及 OPG 上的 6 种影像学表现显著相关，而与性别无关。
大多数 MC 不完整的壁可以通过 OPG 推断出来。但是，基于 CBCT 的图像可以更清楚地显示 MC 的缺陷，并且可以清晰显示根和下牙槽管之间的空间关系。
