上颌第一磨牙近颊第二根管的临床治疗

目的 探讨上颌第一磨牙近烦第二根管（second mesiobuccal canal，MB2）的特征及临床治疗方法。方法 选取患牙髓炎或根尖用炎的上颌第一磨牙95颗，拍摄术前X线片，术中采用小号K锉配合15％EDTA溶液探查根管，记录根管数目、形态和类型；采用机动镍钛器械Hero642进行根管预备，侧向加压充填技术充填根管。结果上颌第一磨牙MB2的发现率为81．1％，扩通的MB2占72．6％，多数MB2根管细小弯曲，需用小号锉配合使用EDTA进行疏通，机动镍钛器械预备根管无明显并发症。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，机动镍钛器械预备可获得良好的治疗效果。

Clinical feature and treatment of the second mesiobuccal canals of permanent maxillary first molars

Objective To evaluate the clinical feature and treatment of second mesiobuccal canal(MB2) of permanent maxillary first molars.Methods The root canals of 95 maxillary first molars were explored with small size K file and(15%) EDTA.The morphology and type of root canal were recorded.The canals of all cases were instrumented by Ni-Ti rotary instruments Hero 642,and obturated with lateral condensation technique.The efficiency of preparation and obturation was analyzed with radiographs before and after treatment.Results The frequency of MB2 canal in maxillary first molars was(81.1%);most of them were fine and curved.(72.6%) of MB2 were negotiated with small size files and EDTA.No complication,such as transportation,ledge and perforation,was found during the treatment.Good result of treatment was achieved in almost all cases.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,and shaped well with Ni-Ti rotary instruments.