多根管下颌前磨牙显微根管治疗的效果观察

目的观察下颌前磨牙多根管的发现率以及显微根管治疗方法处理多根管下颌前磨牙的临床疗效。方法选取152颗需进行根管治疗的下颌前磨牙，拍摄术前X线正位投照片和偏位投照片。对单根管患牙采用常规根管治疗，对怀疑多根管的患牙先常规探查根管，再在显微镜下探查并疏通根管，镍钛机动器械预备根管，垂直加压充填技术充填根管。记录根管类型，使用和未使用显微镜时多根管的发现率，根据术前、术中及术后X线片评价根管预备和充填效果。结果下颌第一前磨牙、第二前磨牙多根管的发现率分别为32．9％、7．5％；使用显微镜多根管的发现率高于未使用显微镜者；治疗中无根管堵塞、偏移、台阶、器械折断等并发症发生，完成治疗的31颗多根管下颌前磨牙30颗适充，1颗超充。结论显微根管治疗是处理多根管下颌前磨牙的有效方法。

Clinical management of mandibular premolars with multiple root canals by using dental operation microscope

Objective To evaluate the root canal morphology of mandibular premolars and the role of dental operating microscope in clinical treatment of lower premolars with multiple canals. Methods 152 mandibular premolars were treated endodontically. Two kinds of preoperative radiographs were taken for each tooth, using straight projection and eccentric projection. The root canal morphology was recorded according to Vertucci＇s classification. Under dental operating microscope, the teeth with multiple root canals were preflared by GG drills, shaped using Ni-Ti rotary instruments ProTaper, cleaned using sodium hypochlorite, and obturated by vertical condensation technique. The number of teeth that were found to have multiple canals was recorded with and without the use of microscope, respectively. The efficiency of preparation and obturation was analyzed with radiographs before, during and after operation. Results The mandibular first premolar had one canal in 67.1% and multiple canals in 32.9% of the teeth. The mandibular second premolar had one canal in 92.5% and multiple canals in 7.5% of the teeth. The treatment with the use of microscope revealed more teeth with multiple canals than that without the use of microscope. There were no transportation, apical blockage, ledge, and instrument fracture in all cases. 146 teeth were filled well, 5 showed slight over-filling, and 1 under-filling. Conclusion Using dental operating microscope, the mandibular premolars with multiple root canals could be treated well.