3种机用镍钛器械在重度弯曲根管预备中根管成形能力的研究

目的：比较机用镍钛Protaper、K3、iRaCe在重度弯曲根管预备中的根管成形能力。方法：收集新鲜拔除的人恒磨牙60颗，要求其中一个根管的弯曲角度为25°～45°，分为Protaper组、K3组和iRaCe组，每组20颗。每颗牙分别在根管预备前后拍摄标准化的平行投照片，通过影像分析来记录根管弯曲度的变化值和根尖偏移量，同时记录折断的器械和根管预备的时间。结果：实验过程中3个组均无器械折断。K3组、iRaCe组在根管预备后根管弯曲角度的变化小于Protaper组，差异有统计学意义（P〈0．05），K3组和iRaCe组之间差异也具有统计学意义（P〈0．05）。Protaper组、K3组的根尖偏移量大于iRaCe组，差异有统计学意义（P〈0．05），Protaper组和K3组之间差异无统计学意义（P〉0．05）。三组在操作时间上的差异无统计学意义（P〉0．05）。结论：iRaCe和K3在重度弯曲根管预备中的根管成形能力较Protaper要好，更适合用于重度弯曲根管预备。

Comparative evaluation of the shaping ability of three kinds of nickel-titanium rotary instruments in severely root canals

Objective： To compare the shaping ability of Protaper, K3 and iRaCe NiTi files during the preparation of severely curved root canals in extracted human molar teeth. Method： Sixty human molars with anyone canals having angles of curvature ranging from 25° to 45° were divided according to the instrument used into three groups of 20 teeth each： group Protaper, group K3 and group iRaCe. Using standardized pre- and post-instrumentation radiographs, straightening of canal curvature and apical transportation were determined using image analysis software. Result： During root canal preparation, no instruments fractured. The use of Protaper resulted in significantly greater canal straightening than K3 and iRaCe （P 〈0.05）, there were also significant differences between K3 and iRaCe （P 〈0.05）. There were significant differences between Protaper, K3 and iRaCe with respect to apical transportation （.P 〈0.05）, but there were no significant differences between Protaper and K3 （P 〉0.05）. There were no significant differences between three groups in using time （P 〉0.05）. Conclu- sion： iRaCe and K3 were better than Protaper in the shaping ability of severely curved root canals.