CBCT分析下颌阻生第三磨牙牙根与下颌管的解剖关系

Analysis of anatomic relationship between mandibular canal and the roots of impacted mandibular third molar by cone beam computed tomography

目的:应用CBCT(Cone Beam Computed Tomography)分析下颌阻生第三磨牙牙根与下颌管的位置关系。方法:从2010-04—2012-04在我院口腔外科诊断为下颌第三磨牙阻生且需拔除的7 751例(15 174个牙)患者中,选择X线片示牙根与下颌管有重叠影像的患者401例(518个中低位下颌阻生第三磨牙)为对象,通过CBCT分析下颌管与牙根的位置关系;并在拔牙术中对X线片和CBCT显示的不同位置关系时下牙槽神经暴露情况进行检查;采用χ2检验对结果进行统计分析。结果:X线片显示有重叠影像的518个牙,CBCT观察显示有343个(66.22%)的牙根与下颌管接触;其中下颌管位于根间者接触发生率最高,依次为根间﹥舌侧﹥根尖下方﹥颊侧(P﹤0.05)。术中检查显示:X线片示有重叠影像的牙术中下牙槽神经暴露者87例牙(16.80%);CBCT显示牙根与下颌管接触时下牙槽神经暴露率为25.36%(87/343),明显高于前者(P﹤0.05)。结论:关于下颌管与下颌阻生第三磨牙牙根的解剖关系,CBCT较X线片能提供更准确的信息。

AIM： To analyze the anatomic relationship between mandibular canal and the roots of impacted mandibular third molar by cone beam computed tomography（CBCT）. METHODS：IS174 teeth in 7751 patients were diagnosed as the impaetion of mandibular third molar in the author＇ s hospital from April 2010 to April 2012. 518 teeth in 401 patients showed roots overlapping with mandibular canal on panoramic radiography were examined by CBCT. During tooth extraction the relationship between mandibular canal and the roots of the impacted teeth was observed. Sta- tistics analysis was performed by X2 test. RESULTS： On CBCT 343 of the 518 teeth（66.22% ） showed root in touch with mandibular canal, mostly the canal was between 2 roots of the molars followed by on the lingual side, below the root tip and on the buecal side（ P 〈 0.05 ）. During tooth extraction exposure of the inferior nerve was found in 87 teeth （ 16.80% ） which were shown roots ovedaooing with mandibular canal on nanoramic radipgranhy, while in 25.36%（87/343） on CBCT（ P 〈 0. 05 ）. CONCLUSION： CBCT can provide more precise information than panoramic radio- graphy for the analysis of anatomic relationship between mandibular canal and the roots of impacted mandibular third molar.