【摘要】 目的　运用手持根管扩大器械预备弯曲根管 ,观察根尖偏移发生率。方法　选取 5 7颗弯曲单根管离体前磨牙作为研究对象 ,随机分成三组 ,A组 19颗用Lightspeed镍钛合金器械预备根管 ,B组运用K锉 ,C组运用H锉 ,预备方法均为逐步后退技术。使用双曝光技术判断根尖偏移情况。结果　A组中有 19%的根管发生了根尖偏移 ,B组中有 82 %发生了根尖偏移 ,C组中有 88%发生了根尖偏移。结论　运用Light speed镍钛器械预备弯根管可以减少根尖偏移的发生。更多还原

【Abstract】 Objective This study is to investigate the occurrence rate of apical transportation with hand endodontic instrument to prepare curved canal.Methods 57 human premolars with single,curved caual were selected,and divided into three groups optionally. The canals with were prepared three commonly hand endodontic instruments which including nickel titanium Lightspeed instrument system, K file, and H file and with step back technique. An apical transportation index was determined by using a double exposure radiographic technique.Results After Lightspeed preparation, apical transportation occurred in 19% of the curved canals. After K file preparation, apical transportation occurred in 82% of the curved canals and after H file preparation is 88%.Conclusion Using nickel titanium Lightspeed instrument system preparing curved canal can reduce the occurrence rate of apical transportation.更多还原