显微超声技术结合CBCT在上颌第一磨牙MB2根管再治疗中的应用

Clinical appliance of cone-beam computed tomography endodontic retreatment of untreated second mesiobuccal canals in treated maxillary first molars

目的:分析应用显微超声技术结合CBCT检查对上颌第一磨牙MB2根管再治疗的临床效果。方法:选择89颗上颌第一磨牙进行显微超声根管再治疗病例,将CBCT的检查结果作为金标准,并依据CBCT影像特征及牙冠与髓底的形态特点判断是否存在MB2,术中采用斜方形开髓入口,小号K锉探查,使用手术显微镜定位MB2根管,镍钛机用根管锉冠向下法预备根管,1.5%次氯酸钠和17%EDTA冲洗根管系统,采用热牙胶垂直加压充填根管,记录近颊根根管分型、根管预备过程中并发症的情况,统计MB2的发现率及根管形态,评价其临床疗效。结果:89颗患牙根管再治疗中,在根管显微镜下去除原根管充填物,并探查MB2,发现MB2 72个。发现率为80.89%(72/89),疏通61个,疏通率68.54%。近颊根双根管以2-1型、2-2型较常见(67.42%)。治疗过程中未发生器械折断、管壁侧穿等并发症,有8个根管超填,6个根管欠填。结论:上颌第一磨牙MB2的发生率高,多数根管细小弯曲,小号K锉配合EDTA疏通根管,应用显微超声技术结合CBCT探查,有意识地寻找和可视化操作,能有效地提高上颌第一磨牙MB2的发现率及根管治疗成功率。

Objective： To observe the clinical feature and evaluate clinical treatment effect of second mesiobuccal canals （MB2 canal） of maxilarry first molars missed in initial endodontic treatment using cone-beam computed tomography （CBCT） and dental operating microscope （DOM）. Method： The root canals of 89 maxillary first molars which need endodontic retreatment were selected. The existence of MB2 canal was determined by radiographs and anatomic features of crown and pulpal floor. With a thapezium path to pulp chamber, the MB2 canals were explored by a small size K file and located using a DOM when needed. The canals were instrumented by Ni-Ti rotary instruments, irrigated by 1.5 % NaOCI and 17 % EDTA were obturated by lateral condensation and vertical compaction technique. The type of mesiobuccal root canals,the in-operative complications and the obturation effect were record. Result：The frequency of MB2 canal in maxillary first molar was 80.89 % （72 / 89） in endodontic retreatment while negotiate rate was 68.54 %. most of them were fine and curved which were negotiated with small size files and EDTA. 2-1 type and 2-2 type were the main type of mesiobuc- cal root canals （67.42 %）. There were no obvious complications during operation. Conclusion： The incidence of MB2 canals in maxillary first molars was high, and most of them were fine and curved. The MB2 canals can be negotiated with small size file and EDTA, Most of MB2 canals were fine, curved and concealed. The management of searching for MB2 canals and the increased visibility afforded with the use of DOM can make the treatment more successful.