3种机用镍钛器械去除根管内充填材料的比较研究

Efficacy of Three Rotary NiTi Instruments in the Removal of Gutta-Percha in Root Canal Retreatment

目的:研究3种机用镍钛器械去除根管内充填材料的能力。方法:80颗下颌第二前磨牙采用改良双敞技术预备根管,热牙胶垂直加压技术充填根管。水浴37℃2周后分为4组,去除根管内牙胶充填物:A组为H锉;B组为机用Protaper;C组为K3;D组为Hero642。记录操作时间。将牙根纵劈,显微镜下观察根管内整体及上、中、下3部分的残留物并评分。将结果进行统计学分析。结果:对于去除根管内充填物,B组所需时间最短,但B、C、D3组之间并无显著性差异;且3组均快于A组(P<0.05)。观察牙根整体及各部分的残留物,A组残留物显著性高于其它3组(P<0.05),而B、C、D3组两两之间均无统计学差异。各组均无器械折断。结论:3种机用镍钛器械均不能完全去除根管内充填材料。但同H锉相比,镍钛器械去除效果更好且操作时间显著减少。

Objective：To evaluate the efficacy of ProTaper,K3 and Hero642 in the removal of gutta-percha during root canal retreatment in comparison with hand Hedstrom files in vitro. Methods：Eighty mandibular second premolars with one canal were prepared and obturated by vertical condensation technique. The teeth were divided into four groups at random and retreated：Group A,H file; Group B,Protaper; Group C,K3; Group D,Hero642. The roots were split longitudinally. The remaining filling materials were observed and scored under microscope. Results：The ProTaper,K3 and Hero642 required significantly less time to remove filling material than hand instruments （P〈0.05）. Group A left significantly more filling material in the entire canal and canal third than Group B,C and D （P〈0.05）. There were no significant differences among the three nickel-titanium instruments regarding the time of retreatment and the scores of remaining filling material. No instruments were fractured. Conclusion：The complete removal of gutta-percha during root canal retreatment is impossible. The retreatment effectiveness of ProTaper,K3 and Hero642 are better than H files.