【作者】 赵瑜；

【机构】 温州医学院附属口腔医院口腔内科；

【摘要】 目的:比较三种方法在发现上颌磨牙MB2根管方面的有效性。方法:选取临床上因各种原因拔除的上颌磨牙194颗,要求牙齿无牙髓治疗史,牙根无龋,无牙根吸收,无髓底破坏。样品被固定于石膏模型中,置于KAVO仿真头模中模仿在体情况。所有牙在开髓、去除髓顶后,按以下步骤进行观察:第一步:由具有丰富临床经验的牙体牙髓科医师通过肉眼观察、器械探查,记录MB2根管存在情况;第二步:同一牙应用手术显微镜镜下观察MB2;第三步:超声锉去除距MB1腭侧3mm的髓底牙本质后,再于镜下观察MB2存在情况。将牙体于石膏模型中取出,去除牙冠、远中及腭侧根,近中颊根于距根尖2mm、4mm和6mm处截断,存在三个截面的任意一个出现两个根管即记录为MB2。结果:应用截根法发现在上颌第一磨牙近中颊根中双根管发生率为52%(102例),应用上述三种方法对于双根管的发现情况分别为:6%(10例),33.5%(65例),49.5%(96例),有显著差异(P<0.05)。结论:应用显微镜和去除髓底部分牙本质在发现MB2方面有效,但是临床上由于根管口钙化、根管分叉部位过低,仍有部分MB2难以发现,增加了根管治疗的难度。更多还原

【Abstract】 AIM:To compare the effectiveness of 3 ways to detect the MB2 canal in mesiobuccal roots of maxillary molar teeth. METHODOLOGY:A total of 194 extracted human maxillary molars were examined.The teeth haven’t the history of root canal therapy,and they have not decay in root,and there is no root recession and the pulp chamber floor damage.Each of the teeth was fixed in a plaster model.To simulate the situation of in vivo,the plaster model was fixed in the simulative head model.After pulp removal,the MB1 and 2 canals in the mesiobuccal root were located in three stages that were performed by two endodontic dentists. Stage 1:canals were located with an endodontic explorer;stage 2:additional canals in the same teeth were located under magnification with a digital microscope;stage 3:additional canals in the same teeth were located by removing dentine(troughing) from the pulp chamber floor within 3 mm from MB1 canal towards the palatal canal with an Enac ultrasonic tip.The specimens were taken from the plaster model.After the crown、the distobuccal root and the palatal root removal,the mesiobuccal root was cut at 2mm、4mm and 6mm from root tip.If there were 2 root canal in any section,this tooth was classed as MB2.RESULTS:More than one canal in the mesio-buccal root was observed in 52%of specimens by cutting root.Detection rates of multiple canals were 6%, 33.5%and 49.5%following stages 1,2 and 3,respectively.There was a significant difference between the stages for detecting the MB2 canal(P<0.05).CONCLUSIONS:Both magnification(stage 2) and dentine removal under magnification(stage 3) were effective in detecting the presence of the MB2 canal.However,MB2 canals could not be detected in all the teeth because of canal calcification or branching located more apically,which increased the root canal therapy difficulty.更多还原