Analysis of anatomical variations of the mandibular canal found on panoramic radiographs

INTRODUCTION: Within the dental clinic blocking the inferior alveolar nerve is the most commonly used, however, several studies have shown higher rates of failure usually have reason to fail in observing the position of the shape and anatomy of the nerves. These failures resulting from anatomic variations of the inferior alveolar nerve have been studied in the literature from studies with the analysis of panoramic radiographs as proposed in this study. OBJECTIVE: The aim of this study was to investigate the occurrence and prevalence of anatomical variations as well as the correlated movements of the jaw with the canals side and sex that may occur in the mandibular canal in panoramic radiographs of patients of the Department of Dentistry, UFS. MATERIAL AND METHOD: Fifteen hundred panoramic radiographs of patients enrolled in the Department of Dentistry, Federal University of Sergipe (UFS) were analyzed radiographic images were observed on a light box using a black mask around the radiographs in an environment with proper lighting. RESULT: In this study 5.3% of bifurcations of the mandibular canal were observed, 47.5% of high canals, 16.8% of intermediate canals, 27.1% to 8.6% lower canals and canals with other variations. CONCLUSION: Based on the height of the mandibular canal was more prevalent among higher canals than other women, and there were no gender differences with respect to other types and affected sides. In the classification of bifid canals there was no statistically significant difference between men and women, the highest prevalence was for canals without bifurcation.

引言：在牙科临床操作中，下牙槽神经阻滞术（inferior alveolar nerve block）是最为常用的术式，但多项研究显示，该操作的失败率偏高，通常源于未能清晰观察神经的形态与解剖位置。这类由下牙槽神经解剖变异引发的操作失败，已有文献通过全景X线片（panoramic radiographs）分析开展相关研究，本研究亦采用该分析思路。
研究目的：本研究旨在针对塞尔吉皮联邦大学（UFS）牙科学院患者的全景X线片，探究下颌管（mandibular canal）解剖变异的发生情况与患病率，同时分析不同下颌管侧别、性别与可能伴随下颌管变异出现的下颌运动特征的关联。
材料与方法：本研究共分析1500例来自塞尔吉皮联邦大学（UFS）牙科学院就诊患者的全景X线片。阅片过程在光照条件适宜的环境中开展，将X光片置于观片灯下，通过环绕片子的黑框遮罩辅助观察影像细节。
结果：本研究共观察到5.3%的下颌管分叉变异病例、47.5%的高位下颌管、16.8%的中位下颌管、27.1%的低位下颌管及8.6%的其他类型下颌管变异。
结论：就下颌管高度分型而言，高位下颌管在女性群体中的患病率高于其他类型下颌管；其余类型解剖变异及受累侧别均未发现显著性别差异。在分叉型下颌管的组间比较中，未发现男女间存在统计学显著差异，且无分叉的下颌管整体患病率最高。