微焦点计算机扫描技术评价不同器械清除根管充填材料效率的研究

Efficacy of Root Canal Filling Material Removal by Different Instruments Using Micro-computed Tomography

目的:通过微焦点计算机扫描技术评价镍钛器械、超声器械及手用不锈钢器械清除椭圆形根管内充填物的效率。方法:收集椭圆形下颌单根管前磨牙,经K3镍钛器械冠向下法预备、冷牙胶侧方加压充填,选取具有椭圆形根管的牙齿随机分为5组,分别用手用H锉器械、机用K3器械、Mtwo器械、R-Endo器械、超声P5去除根管内充填物。微焦点计算机断层扫描并通过自带软件计算各组根管中充填物清除前后的体积,进一步计算不同器械清除根管内充填物的清除百分率,同时记录各个器械清除根管内充填物所用的时间。结果:手用H锉器械对根管内充填物的清除率大于Mtwo器械、超声P5,且具有统计学差异(P<0.05);手用器械对根管内充填物的清除率与机用K3器械、R-Endo器械无统计学差异(P>0.05)。操作时间方面,手用H锉器械组操作时间长于其余4组,与其余4组均有统计学差异(P<0.05)。结论:椭圆形根管内,使用机用镍钛器械可以减少操作时间,但是并不能减少残留的根管充填物。

Objective:To evaluate the efficacy of removing filling materials from oval-shaped root canals by nickel-titanium instruments,ultrasonic instruments and hand instruments by Micro-CT(Micro-CT).Methods:Human mandibular premolars with single root canal were collected and prepared by K3 nickel-titanium instruments with crown-down technique,and then filled by cold lateral compaction.Oval-shaped root canals were randomly assigned into five groups,and retreated by the following techniques respectively:Hedstrom files,K3,Mtwo,R-Endo,and ultrasonic P5.Micro-CT was used to assess the volume of filling material before and after the removal procedure.Based on the volume of initial and residual filling material of each specimen,the percentage of filling material removed from the root canals by different techniques was calculated.Meanwhile,the time taken by various instruments to remove the root canal filling was recorded.Results:Hedstrom file group showed a greater filling material removal rate than Mtwo and ultrasonic P5 groups(P<0.05).There was no significant difference in the removal efficacy among Hedstrom file,K3 instrument,and R-Endo instrument groups(P>0.05).The time needed for manual Hedstrom file was significantly longer than the other four groups(P<0.05).Conclusion:In the oval root canals,nickel-titanium instruments can reduce the operating time compared with manual Hedstrom file.