Li Mei-Lin, Liao Wei-Li, Cai Hua-Xiong
Department of Oral Medicine, Haizhu Square Branch, Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, Guangdong 510280, P.R. China.
Zhujiang New Town Dental Clinic, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China.
Exp Ther Med. 2018 Jan;15(1):494-499. doi: 10.3892/etm.2017.5399. Epub 2017 Oct 30.
The aim of the present study was to evaluate the length of dentinal microcracks observed prior to and following root canal preparation with different single-file nickel-titanium (Ni-Ti) systems using micro-computed tomography (micro-CT) analysis. A total of 80 mesial roots of mandibular first molars presenting with type II Vertucci canal configurations were scanned at an isotropic resolution of 7.4 µm. The samples were randomly assigned into four groups (n=20 per group) according to the system used for root canal preparation, including the WaveOne (WO), OneShape (OS), Reciproc (RE) and control groups. A second micro-CT scan was conducted after the root canals were prepared with size 25 instruments. Pre- and postoperative cross-section images of the roots (n=237,760) were then screened to identify the lengths of the microcracks. The results indicated that the microcrack lengths were notably increased following root canal preparation (P<0.05). The alterations in microcrack length in the OS group were more significant compared with those in the WO, RE and control groups (P<0.05). In conclusion, the formation and development of dentinal microcracks may be associated with the movement caused by preparation rather than the taper of the files. Among the single-file Ni-Ti systems, WO and RE were not observed to cause notable microcracks, while the OS system resulted in evident microcracks.
本研究的目的是使用显微计算机断层扫描（micro-CT）分析，评估在使用不同的单根镍钛（Ni-Ti）系统进行根管预备之前和之后观察到的牙本质微裂纹的长度。对总共80颗呈现II型Vertucci根管形态的下颌第一磨牙的近中根，以7.4µm的各向同性分辨率进行扫描。根据用于根管预备的系统，将样本随机分为四组（每组n = 20），包括WaveOne（WO）组、OneShape（OS）组、Reciproc（RE）组和对照组。在用25号器械预备根管后，进行第二次micro-CT扫描。然后筛选根的术前和术后横截面图像（n = 237,760）以确定微裂纹的长度。结果表明，根管预备后微裂纹长度显著增加（P<0.05）。与WO组、RE组和对照组相比，OS组微裂纹长度的变化更显著（P<0.05）。总之，牙本质微裂纹的形成和发展可能与预备引起的移动有关，而不是与锉的锥度有关。在单根Ni-Ti系统中，未观察到WO和RE会引起明显的微裂纹，而OS系统会导致明显的微裂纹。
