曲面断层片显示下颌第三磨牙牙根与下牙槽神经管关系困难情况下的CBCT研究

Position of the mandibular canal in relation to the mandibular third molar studied by CBCT and panoramic radiograph

目的CBCT在曲面断层片在下颌第三磨牙牙根与下牙槽神经管关系显示困难情况下的应用和对比。方法对曲面断层片中提示下颌第三磨牙牙根与下牙槽神经管接触或重叠的患者,使用CBCT分析下颌第三磨牙牙根与下牙槽神经管的位置关系。结果曲面断层片中高、中、低位阻生的下颌第三磨牙在CBCT中神经管缺损发生率分别为26.19%、44.83%、68.75%,结果有统计学差异。下牙槽神经管位于下颌第三磨牙牙根的颊侧最多见,其次为神经管位于牙根下方、舌侧、牙根间,当神经管位于舌侧和牙根之间时,神经管发生缺损的概率最高,其次是神经管位于牙根下方,当神经管位于颊侧时发生缺损的概率较低,结果有统计学差异。结论对于曲面断层片不能明确下颌第三磨牙与下颌管关系时,加拍CBCT,确认下牙槽神经管的位置,避免神经损伤。

Objective To determine the positional relationship between mandibular third molar and mandibular canal by CBCT.Methods A total of 103 mandibular third molars with root apexes contacted to mandibular canal on panoramic radiograph were further examined by CBCT,and the exact positional relationship between mandibular third molars and mandibular canals was observed and analyzed.Results The 103 mandibular third molars were impacted at high,middle and low positions on panoramic radiograph.The rate of the canal defect observed by CBCT images was 26.19%,44.83%and 68.75%respectively.Mandibular canals were found on the buccal side,lingual side,under the mandibular third molars and between the root apexes.Conclusion CBCT examination is necessary for the determination of the positional relationship between mandibular canal and mandibular third molar with the root apex contacted or overlapped on panoramic radiograph.