Pettiette M T, Metzger Z, Phillips C, Trope M
Department of Endodontics, University of North Carolina School of Dentistry, Chapel Hill 27599, USA.
J Endod. 1999 Apr;25(4):230-34. doi: 10.1016/S0099-2399(99)80148-4.
Straightening of curved canals is one of the most common procedural errors in endodontic instrumentation. This problem is commonly encountered when dental students perform molar endodontics. The purpose of this study was to compare the effect of the type of instrument used by these students on the extent of straightening and on the incidence of other endodontic procedural errors. Nickel-titanium 0.02 taper hand files were compared with traditional stainless-steel 0.02 taper K-files. Sixty molar teeth comprised of maxillary and mandibular first and second molars were treated by senior dental students. Instrumentation was with either nickel-titanium hand files or stainless-steel K-files. Preoperative and postoperative radiographs of each tooth were taken using an XCP precision instrument with a customized bite block to ensure accurate reproduction of radiographic angulation. The radiographs were scanned and the images stored as TIFF files. By superimposing tracings from the preoperative over the postoperative radiographs, the degree of deviation of the apical third of the root canal filling from the original canal was measured. The presence of other errors, such as strip perforation and instrument breakage, was established by examining the radiographs. In curved canals instrumented by stainless-steel K-files, the average deviation of the apical third of the canals was 14.44 degrees (+/- 10.33 degrees). The deviation was significantly reduced when nickel-titanium hand files were used to an average of 4.39 degrees (+/- 4.53 degrees). The incidence of other procedural errors was also significantly reduced by the use of nickel-titanium hand files.
弯曲根管的拉直是牙髓治疗器械操作中最常见的程序性错误之一。牙科学生在进行磨牙牙髓治疗时经常遇到这个问题。本研究的目的是比较这些学生使用的器械类型对根管拉直程度和其他牙髓治疗程序性错误发生率的影响。将镍钛0.02锥度手动锉与传统的不锈钢0.02锥度K锉进行比较。60颗磨牙，包括上颌和下颌第一、第二磨牙，由高年级牙科学生进行治疗。使用镍钛手动锉或不锈钢K锉进行器械操作。使用带有定制咬块的XCP精密器械对每颗牙齿进行术前和术后X光片拍摄，以确保X光片角度的准确再现。X光片被扫描，图像存储为TIFF文件。通过将术前的描图叠加在术后X光片上，测量根管充填根尖三分之一处相对于原始根管的偏差程度。通过检查X光片确定是否存在其他错误，如牙本质侧穿和器械折断。在使用不锈钢K锉进行器械操作的弯曲根管中，根管根尖三分之一处的平均偏差为14.44度（±10.33度）。当使用镍钛手动锉时，偏差显著降低，平均为4.39度（±4.53度）。使用镍钛手动锉也显著降低了其他程序性错误的发生率。
