下颌第二磨牙C形根管治疗分析

目的分析下颌第二磨牙根管治疗过程中C形根管的解剖特征及治疗方法。方法选择因牙髓病或根尖周病初次就诊、需做根管治疗的下颌第二磨牙100例，通过拍摄术前X线片和术中根管探查，按照Melton标准诊断C形根管；记录根管数目、形态和类型，最后以手用ProTaper镍钛锉预备根管。结果下颌第二磨牙C形根管的发现率为28．57％（32／112），81％的C形根管患牙X线片表现为锥形融合牙根，19％表现为近远中独立牙根：所有患牙均无根管内并发症发生，治疗效果理想。结论下颌第二磨牙C形根管主要存在于融合牙根．根管探查结合X线片可诊断C形根管：EDTA配合ProTaper手用镍钛器械进行根管预备，次氯酸钠冲洗可获得良好的治疗效果。

Treatment analysis of C-shaped root canals in mandibular second molars

Objective To analyze anatomical characteristics and therapeutic methods of C-shaped root canals in the root canal treatment of mandibular second molars. Methods The 100 mandibular second molars due to pulposis or periapical disease for root canal therapy in first-time consuhancy were selected. The C-shaped root canals were diagnosed by preoperative X-ray films and intraoperative canal exploration based on the criteria of Melton. The root canals were shaped by band-manipulated Ni-Ti ProTaper before recording their amount, shape, and type. Results The inci- dence of C-shaped canals in mandibular second molars was 28.57%（32/112）. According to X-ray films, 81% teeth with C-shaped canals had conical fusion roots, and 19% of C-shaped canal teeth revealed the distinct mesial and distal roots. There was no any complication in all cases. The therapeutic effect was favorable. Conclusion The C-shaped canal system in mandibular second molars mainly displays in a fused root, which can be diagnosed by X-ray films and canal exploration. The therapy of root canals shaped by ethylene diamine tetraacetic acid （EDTA） combining with hand-manipulated Ni-Ti instrument ProTaper and cleaned by sodium hypochlorite can obtain a good therapeutic effect.