Synchrotron radiation-based micro-computed tomographic analysis of dentinal microcracks using rotary and reciprocating file systems: An in vitro study

Background: Advances in both X-ray sources and X-ray optics have dramatically improved the feasibility of these techniques in various fields. Aims: We aimed to evaluate the frequency of dentinal microcracks observed after root canal preparation with ProTaper Gold (PTG), Hyflex electrodischarge machining (HEDM), Reciproc (RPC), and WaveOne Gold (WOG) using synchrotron radiation-based micro-computed tomographic (SR-μCT) analysis. Subjects and Methods: Forty mandibular molars were assigned to 4 experimental groups (n = 10) according to the file system used for the root canal preparation: Group 1: PTG (25/0.08), Group 2: HEDM (25/0.08), Group 3: RPC (25/0.08), and Group 4: WOG (25/0.07). The specimens were scanned on SR-μCT system before and after root canal preparation. The pre- and postoperative cross-sectional images (N = 183,200) of the mesial roots were screened to identify the presence of dentinal microcracks. The number of microcracks was determined as a percentage for each group. Statistical Analysis: There was no necessity of statistical analysis in the present study. The number of microcracks was determined as a percentage for each group. Results: Among the four file systems tested, HEDM (0.9%) has shown a fewer number of new dentinal microcracks. Conclusions: SR-μCT can be used as a reliable diagnostic tool for further implications.