口腔曲面断层片评估下颌第三磨牙拔除术中神经管损伤的影响因素分析

Analysis of the influencing factors of neural tube injury in mandibular third molar extraction by panoramic tomography

目的:在曲面断层片上测量下颌阻生第三磨牙(impacted mandibular third molar,IMTM)周围相关指标,分析IMTM拔除术中下牙槽神经管损伤的影响因素。方法:对拟拔除IMTM病人108例行术前曲面断层片检查,测量IMTM周围的相关指标,包括下牙槽神经管清晰度、阻生牙距下牙槽神经管上壁的距离、阻生牙的Pell&Gregory分类等。按照标准拔除阻生牙手术操作步骤拔除IMTM,拔牙术后利用钝头探针检查拔牙创底有无神经管损伤,分析IMTM拔除术中下牙槽神经管损伤的影响因素。结果:108例病人共拔除193颗IMTM,术中探及下牙槽神经管壁损伤38例,术后出现下唇麻木4例,麻木率2.07%;下牙槽神经管壁无损伤155例,均未出现下唇麻木。损伤与未损伤病人在IMTM是否弯根、神经管上下壁是否清晰、Pell&Gregory分类、IMTM距管上壁距离、IMTM与MSM长轴夹角方面差异均有统计学意义(P<0.01)。Logistic回归分析结果显示,IMTM是否弯根、神经管上下壁是否清晰、IMTM距管上壁距离、IMTM与MSM长轴间夹角均为IMTM拔除术中损伤下牙槽神经管壁的独立危险因素(P<0.05~P<0.01)。结论:通过口腔曲面断层片可以较好的评估IMTM拔除术中下牙槽神经管损伤的危险因素,本研究所观察的指标对临床指导拔除下颌阻生牙有一定的指导意义。

Objective:To measure the relevant data of impacted mandibular third molar(IMTM)by panoramic radiography,and analyze the influencing factors of inferior alveolar tube injure during extraction of IMTM.Methods:The preoperative curved radiograph examination in 108 patients with IMTM were implemented,and the relevant indexes around IMTM,which included the clarity of inferior alveolar nerve canal;distance between impacted tooth from upper wall to inferior alveolar nerve and Pell&Gregory classification of impacted teeth,were measured.The IMTM were removed according to the standard surgical procedure.After the extraction of teeth,a blunt head probe was used to detect a nerve tube damage,and the influencing factors of inferior alveolar tube injure during extraction of IMTM were analyzed.Results:A total of 193 IMTM in 108 patients were extracted,38 cases with inferior alveolar nerve injury and 4 cases with numbness in lower lip(the numbness rate for 2.07%)were found.One hundred and fifty-five cases without inferior alveolar nerve injury and numbness in the lower lip were identified.The differences of the curved root of IMTM,clear upper and lower wall of neural tube,Pell&Gregory classification,distance from IMTM to upper wall of neural tube and angle between IMTM and MSM on the long axis were statistically significant between patients with and without injury(P<0.01).The results of logistic regression analysis showed that the curved root of IMTM,clear upper and lower wall of neural tube,Pell&Gregory classification,distance from IMTM to upper wall of neural tube and angle between IMTM and MSM on the long axis were the independent risk factor of lower alveolar nerve wall injury during IMTM extraction(P<0.05 to P<0.01).Conclusions:The oral surface tomography can better evaluate the risk factors of inferior alveolar neural tube injury during the extraction of IMTM.The indicators have certain guiding significance for the clinical guidance of the extraction of IMTM.