Dentinal Microcrack Development after Canal Preparation: A Longitudinal in Situ Micro–computed Tomography Study Using a Cadaver Model

Abstract

IntroductionThe purpose of this study was to evaluate the development of dentinal microcracks after root canal preparation with Reciproc and ProTaper Universal systems using an in situ cadaver model by means of a micro–computed tomography (micro-CT) imaging system. MethodsAt autopsy, 8 maxillary bone blocks having at least the first and second premolar teeth (n = 16) were excised, scanned at a resolution of 13.18 μm, and randomly distributed into 2 groups (n = 8) according to the preparation protocol: Reciproc and ProTaper Universal systems. Root canals were prepared up to R25 and F2 instruments in the Reciproc and ProTaper Universal groups, respectively. After the preparation procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 19,060) were screened to identify the presence of dentinal defects. ResultsIn the Reciproc group, 9176 cross-section images were analyzed, and no crack was observed. In the ProTaper Universal group, 244 of 9884 cross-section slices (2.46%) had dentinal defects; however, all defects were already present in the corresponding preoperative images, indicating that no new microcrack was created after canal preparation. ConclusionsIn situ root canal preparation of maxillary premolars with Reciproc and ProTaper Universal systems did not induce the formation of dentinal microcracks in a cadaver model as observed by micro–CT.