两种根管镍钛器械中心定位能力及抗折能力的研究

Study on the central positioning ability and fracture resistance of two kinds of nitinol instruments

目的评估M3、M3-Pro镍钛锉预备弯曲根管后的中心定位能力及器械损伤情况,为临床中安全使用M3系列根管镍钛器械提供实验参考。方法(1)将20个树脂模拟根管分为两组,分别使用M3、M3-Pro进行根管预备,记录每组的根管预备时间,使用扫描仪获取2组模拟根管预备前后的图像,将根管预备前后的图像重叠并测量根管预备前后的偏移情况,比较2组器械的中心定位能力。(2)选用M3、M3-Pro机用镍钛锉各13套,每种镍钛锉分为A组6套,B组6套,对照组1套。A组预备中度弯曲根管,B组预备重度弯曲根管。每预备1个根管,在体式显微镜下观察镍钛锉表面磨耗损伤情况并与新锉比较。结果(1)M3、M3-Pro机用镍钛锉在根管全长皆显示出了较好的中心定位能力(P>0.05);预备时间M3、M3-Pro相似(P>0.05)。(2)预备中度弯曲根管,两组镍钛锉共29支出现缺损或螺纹变形,无器械分离;预备重度弯曲根管两组镍钛锉共31支出现缺损或螺纹变形,3支器械分离。结论(1)M3系列镍钛锉均具有良好的中心定位能力,预备时间与器械支数密切相关;(2)使用M3系列机用镍钛锉预备中度弯曲根管建议次数12~16次,预备重度弯曲根管建议次数7~9次。

Objective To evaluate the central positioning ability and instrument damage of M3 and M3-Pro nitinol files after preparing curved root canals,so as to provide experimental reference for the safe use of M3 series nitinol instruments in clinical practice.Methods(1)20 resin simulated root canals were divided into two groups,M3 and M3-Pro were used for root canal preparation respectively,the root canal preparation time of each group was recorded,the images before and after simulated root canal preparation were obtained by scanner,the images before and after simulated root canal preparation were overlapped,the offset before and after root canal preparation was measured,and the center positioning ability of two groups of instruments was compared.(2)13 sets of M3 and M3-Pro nitinol files were selected.Each nitinol file was divided into 6 sets in group A,6 sets in group B and 1 set in control group.Group A prepared moderately curved root canals,group B prepared severely curved root canals.For each root canal prepared,the surface abrasion damage of Ni Ti files was observed under stereomicroscope and compared with that of new files.Results(1)Both M3 and M3-Pro nickel titanium files showed a good ability of central positioning in the whole length of root canal(P>0.05);the preparation time of M3 and M3 Pro was similar(P>0.05).(2)For moderately curved root canals,29 nitinol files in two groups had defects or thread deformation,and no instruments were separated;for severely curved root canals,31 nitinol files in two groups had defects or thread deformation,and 3 instruments were separated.Conclusion(1)M3 series nitinol files have good ability of central positioning,and the preparation time is closely related to the number of instruments;(2)The recommended number of times to prepare moderately curved root canals with M3 series nitinol files is 12~16,and the recommended number of times to prepare severely curved root canals is 7~9.