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Micro-computed Tomographic Evaluation of Dentinal Microcrack Formation after Using New Heat-treated Nickel-titanium
H Melike Bayram1, Emre Bayram1, Mert Ocak2
1Department of Endodontics, Faculty of Dentistry, Gaziosmanpaşa University, Tokat, Turkey.
Introduction:
The aim of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with HyFlex CM (Coltène/Whaledent, Altstätten, Switzerland), HyFlex EDM (Coltène/Whaledent), Vortex Blue (Dentsply Tulsa Dental Specialties, Tulsa, OK), and TRUShape (Dentsply Tulsa Dental Specialties) systems using micro-computed tomographic (micro-CT) analysis.
Methods:
Forty human mandibular incisors with 1 and straight root canals were randomly assigned to 4 experimental groups (n = 10) and 1 control group for root canal preparation: group 1, HyFlex CM; group 2, HyFlex EDM; group 3, Vortex Blue; and group 4, TRUShape. The specimens were scanned using high-resolution micro-CT imaging before and after root canal preparation. Afterward, preoperative and postoperative cross-sectional images of the teeth were screened to identify the presence of dentinal defects. The number of microcracks was determined as a percentage for each group.
Results:
Before and after canal preparation, 36,152 cross-sectional images were examined. Four thousand four hundred fifty-two (12.31%) dentinal defects were observed. No new microcracks were observed after root canal instrumentation with the tested systems.
Conclusions:
Root canal preparation with the HyFlex CM, HyFlex EDM, Vortex Blue, and TRUShape systems did not induce the formation of new dentinal microcracks on straight root canals of mandibular incisors.

