Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California; Department of Conservative Dentistry, School of Dentistry, Complutense University, Madrid, Spain.
J Endod. 2017 Dec;43(12):2070-2073. doi: 10.1016/j.joen.2017.07.008. Epub 2017 Sep 28.
This study assessed the frequency of dentinal microcracks using a cadaver mandible model in teeth instrumented with TRUShape (TS; Dentsply Sirona, York, PA), WaveOne Gold (WO, Dentsply Sirona), or K-files (KF) compared with an uninstrumented control group (CG).
Fifteen human mandibles with 95 single-rooted teeth were randomly distributed into the following groups: CG (no preparation, n = 11), TS (n = 28), WO (n = 28), and KF (step-back preparation with K-Flex-o-files [Dentsply Sirona], n = 28). Teeth were prepared to apical sizes of #25/.06 or #25/.07; overlying bone was removed, and then teeth were lifted out of the socket and sectioned at 3, 6, and 9 mm from the apex using a low-speed saw. Resulting slices were photographed at 20× and 25× magnification. Three independent and blinded evaluators assessed the images for the presence of dentinal microcracks and their extension, direction, and location. The chi-square test was used for statistical analysis (P < .05).
In the final sample of 83 teeth for the 4 groups, microcracks were found in 10 of 33, 13 of 66, 16 of 69, and 21 of 81 sections for CG, TS, WO, and KF, respectively. There were no significant differences in the frequency of microcracks among the CG, TS, WO, or KF instruments overall or when comparing section levels (3 mm [P = .9], 6 mm [P = .18], or 9 mm [P = .69], respectively, from the apex). There were also no significant differences in the extension, direction, or location of the dentinal microcracks among all groups (P > .05).
There was no difference in the frequency of microcracks among the experimental groups instrumented with TS, WO, and KF or uninstrumented controls.
本研究使用尸体下颌骨模型评估了使用 TRUShape（TS；登士柏西诺德，约克，宾夕法尼亚州）、WaveOne Gold（WO，登士柏西诺德）或 K 型锉（KF）器械预备的牙齿与未器械预备的对照组（CG）之间牙本质微裂纹的频率。
15 个人类下颌骨共有 95 颗单根牙，随机分为以下组：CG（无预备，n=11）、TS（n=28）、WO（n=28）和 KF（用 K-Flex-o 锉[登士柏西诺德]进行后退预备，n=28）。牙齿预备到#25/.06 或#25/.07 根尖尺寸；去除上方骨组织，然后将牙齿从牙槽窝中取出，并用低速锯在距根尖 3、6 和 9mm 处切成切片。用 20×和 25×放大倍数拍摄所得切片。3 名独立且盲法评估员评估图像中牙本质微裂纹的存在及其延伸、方向和位置。使用卡方检验进行统计分析（P<.05）。
在 4 个组的 83 颗最终样本牙齿中，CG、TS、WO 和 KF 组的 33、66、69 和 81 个切片中分别发现微裂纹 10、13、16 和 21 个。CG、TS、WO 或 KF 器械之间微裂纹的总体频率或从根尖处 3mm（P=0.9）、6mm（P=0.18）或 9mm（P=0.69）处比较切片水平时均无显著差异。各组微裂纹的延伸、方向或位置也无显著差异（P>.05）。
用 TS、WO 和 KF 器械预备的实验组或未器械预备的对照组之间微裂纹的频率无差异。
