镍钛器械不同运动方式根管预备后牙根微裂的体外研究

Dentinal crack formation during root canal preparations using reciprocating and rotary files

目的:比较Waveone与Pro Taper Universal镍钛器械采用不同运动方式根管预备后牙根微裂的发生。方法:40颗离体下颌切牙随机分成4组(n=10),实验组分别使用Waveone Primary单支锉往复式运动、Pro Taper Universal F2单支锉往复式运动、Pro Taper Universal全序列至F2连续旋转运动模式预备根管,对照组不进行根管预备。根管预备后,距根尖孔3 mm、6 mm、9 mm处进行水平切盘,体视显微镜下观察牙根不同横截面牙根微裂的发生情况。结果:对照组未观察到牙根微裂。实验组中,Waveone Primary单支锉往复式运动组、Pro Taper Universal F2单支锉往复式运动组和Pro Taper Universal全序列连续旋转运动组产生根裂的比例分别为20%、30%和60%。往复式运动组和连续旋转运动组之间差异均有统计学意义(P<0.05),Waveone Primary单支锉组和Pro Taper Universal F2单支锉组差异无显著性(P>0.05)。结论:机用镍钛器械采用往复式运动可减少牙根微裂的发生。

Objective：To compare the incidence of dentinal cracks after root canal preparation with instruments working in continuous rotation and reciprocating motion. Method：40 extracted mandibular central incisors with mature apices and straight root canals（5°~10°） were selected and kept in saline. Group A samples were prepared with Wave One primary files,group B samples with single F2 Pro Taper working in reciprocating motion,group C samples with sequential Pro Taper until F2 working in continuous rotation motion,and group D samples were the negtive control. Roots were then horizontally sectioned 3,6,and 9 mm from the apex. The slices were viewed through a stereomicroscope at ×25magnification. The samples were photographed with a camera to determine the presence of dentinal cracks. Result：The control group had no cracks. Waveone,single F2 Pro Taper in reciprocating motion,and continuous Pro Taper groups caused cracks in 20 %,30 %,and 60 % of samples,respectively. A statistically significant difference was found between 2reciprocating file groups（Wave One and single F2 Pro Taper in reciprocating motion） and the continuous rotation group（Pro Taper）（P〈0.05）. However,no significant difference was found among the 2 reciprocating file groups（P〈0.05）.Conclusion：Dentinal cracks were less occured with instruments working in reciprocating motion compared with those working in continuous rotation.