ProTaper和TF的根管偏移的μCT比较研究

A Comparison of Canal Transportation of Twisted Files and ProTaper by Using Microcomputed Tomography

目的:通过μCT来研究对比2种机用镍钛系统:ProTaper和TF在离体牙根管预备中产生的偏移。方法:选取远颊根弯曲度不超过20°且近颊根弯曲度不低于20°的24颗上颌第一磨牙,作为研究对象。所有牙齿被随机分为2组,每组12颗牙,24个根管。1组的近颊根(M1)和2组的远颊根(D2)使用TF进行预备;1组的远颊根(D1)和2组的近颊根(M2)使用ProTaper进行预备。用μCT对预备前后的牙齿分别进行每25μm为一层的扫描,将距离根尖3mm,5mm和7mm的影像导入图像分析软件进行根管预备前后中心点的距离测量,从而对预备前后的根管偏移进行分析。结果:所有根管均存在偏移。无论是在直根管还是弯曲根管的三个横截面中,TF预备产生的根管偏移都要明显小于ProTaper。结论:在离体牙根管预备中,TF维持原有根管形态的能力要远远优于ProTaper。

Objective： To compare the canal transportation between two rotary nickel-titanium （NiTi） systems： Twisted files （TF） and ProTaper （PT） by microcomputed tomography （μCT）. Methods： 24 extracted human maxillary first molars with distobuccal canals （with curvature angles no more than 20%） and mesiobuccal canals （with curvature angles beyond 20%） were selected and divided randomly into 2 groups with 12 teeth and 24 canals each. The mesiobuccal canals of group 1（Group M1） and the distobuccal canals of group 2 （Group D2） were instrumented by TF. The distobuccal canals of group1 （Group D1） and the mesiobuccal canals of group 2 （Group M2） were instrumented by PT. To compare the canal transportation produced by the two instruments, the teeth were scanned per 25μm from the foramen byμCT before and after instrumentation. The images were reconstructed and cross- sections to distance 3, 5 and 7 mm from the anatomic apex were exported to Adobe Photoshop software for analysis. The distance between the preprepared canals center and the postprepared canals center were measured to evalu- ate the canal transportation. Results： Transportation occurred in all the groups. Statistically, there was significant difference between TF and ProTaper. In contrast, no matter the canals were flat or curved the transportation of canals prepared by TF was obviously lesser than the canals of prepared by ProTaper. Conclusion： Under the conditions of the study, the TF system was found to be better in maintaining the original center of the root canal system than ProTaper.