Effects of Reciproc, ProTaper Next and WaveOne Gold on Root Canal Walls: A Stereomicroscope Analysis

Introduction: The aim of this study was to analyse the potential occurrence of dentinal defects after root canal preparation using three engine-driven instruments. Methods and Materials : Eighty permanent mandibular incisors were selected. Twenty teeth did not undergo preparation, and the remaining teeth were divided into three groups ( n =20): Reciproc (REC) , ProTaper Next (PTN) and WaveOne Gold (WOG). The samples were dyed with methylene blue, sectioned perpendicularly to the long axis in 3-, 6- and 9-mm slices and were finally observed under a stereomicroscope (under 25×). The absence/presence of dentinal defects was documented by two blind observers. The data were analysed using Pearson’s chi -squared test with a confidence level of 95% ( P =0.05). The time to prepare the samples was recorded, and the groups were compared using F -test (ANOVA). Results: The control group did not present any defects, and the differences between the control and experimental groups were statistically significant ( P <0.05). WOG, PTN and REC caused microcracks on 60%, 33.33% and 18.33% of the samples, respectively. No significant differences between the groups in the 3-mm sections ( P =0.126) were observed. There were significant differences in the 6-mm ( P =0.042) and 9-mm sections ( P <0.001). When WOG and PTN were used to perform root canal preparation, a significant difference was found in the average time ( P =0.047). Conclusion: All the used instruments caused dentinal defects in the root dentin. All the instruments were used to perform the preparation with a similar average time. Keywords: Dentinal Defects; Microcracks; Nickel-Titanium Instruments; Root Canal Preparation