Department of Endodontics, Faculty of Dentistry, University of Cukurova, Adana, Turkey.
J Endod. 2012 Feb;38(2):232-5. doi: 10.1016/j.joen.2011.10.011. Epub 2011 Dec 5.
The purpose of this study was to compare dentinal microcrack formation while using hand files (HFs), 4 brands of nickel-titanium (NiTi) rotary files and the self-adjusting file.
One hundred forty mandibular first molars were selected: 20 teeth were left unprepared and served as control, and the remaining 120 teeth were divided into 6 groups. HFs, HERO Shaper (HS; Micro-Mega, Besancon, France), Revo-S (RS, Micro-Mega), Twisted File (TF; SybronEndo, Orange, CA), ProTaper (PT, Dentsply Maillefer), and SAFs were used to prepare the 2 mesial canals. Roots were then sectioned 3, 6, and 9 mm from the apex, and the cut surface was observed under a microscope and checked for the presence of dentinal microcracks.
The control, HF, and SAF groups did not show any microcracks. In roots prepared with the HS, RS, TF, and PT, dentinal microcracks were observed in 60%, 25%, 44%, and 30% of teeth, respectively. There was a significant difference between the control/HF/SAF group and the 4 NiTi rotary instrument groups (P < .0001). However, no significant difference was found among the 4 NiTi rotary instruments (P > .005).
All rotary files created microcracks in the root dentin, whereas the SAF file and hand instrumentation presented with satisfactory results with no dentinal microcracks.
本研究旨在比较手动根管锉（HFs）、4 种镍钛（NiTi）旋转锉和自调锉在使用时牙本质微裂纹的形成情况。
选择 140 颗下颌第一磨牙：20 颗牙未经预备作为对照，其余 120 颗牙分为 6 组。使用 HFs、Hero Shaper（HS；Micro-Mega，Besancon，法国）、Revo-S（RS，Micro-Mega）、Twisted File（TF；SybronEndo，Orange，CA）、ProTaper（PT，Dentsply Maillefer）和 SAFs 预备近中 2 根管。然后从根尖向 3、6 和 9 mm 处将根部分段，在显微镜下观察切面并检查牙本质微裂纹的存在情况。
对照组、HF 组和 SAF 组均未发现微裂纹。在 HS、RS、TF 和 PT 预备的根中，分别有 60%、25%、44%和 30%的牙齿出现牙本质微裂纹。对照组/HF/SAF 组与 4 种 NiTi 旋转器械组之间存在显著差异（P<.0001）。然而，4 种 NiTi 旋转器械之间无显著差异（P>.005）。
所有旋转锉都在根管牙本质中产生微裂纹，而 SAF 锉和手动器械的效果令人满意，无牙本质微裂纹。
