Evaluating In Vitro Performance of Novel Nickel-Titanium Rotary System (TruNatomy) Based on Debris Extrusion and Preparation Time from Severely Curved Canals

Introduction: This laboratory-based study aimed to investigate the quantitative amount of apically extruded debris from severely curved root canals and the preparation time for the novel rotary system TruNatomy (TN; Dentsply Sirona, Charlotte, NC) compared with Reciproc Blue (RCB; VDW Dental, Munich, Germany), HyFlex (HyFlex Controlled Memory [HCM; Coltene/Whaledent, Altstatten, Switzerland] and HyFlex EDM [HEDM, Coltene/Whaledent]), and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) rotary systems. Methods: One hundred mandibular molar human teeth with severe curvature of the mesiobuccal canal (25 degrees-45 degrees) were included in the present study. The specimens were randomly distributed into 5 balanced groups (n = 20): TN, RCB, HCM, PTN, and HEDM. The amount of extruded debris for each group during instrumentation at body temperature was collected in an Eppendorf tube. After desiccation, the mean debris weights for each group were calculated. The total preparation time for each group was also recorded. Data were statistically analyzed using the Kruskal-Wallis test at a significance level of P < .05. Results: The HCM and HEDM groups extruded a significantly higher amount of debris than the other tested groups (P < .001). TN extruded the least amount of debris, but it was not significantly different compared with the RCB and PTN groups (P > .05). In terms of preparation time, the TN group did not show any significant difference compared with the other groups. Conclusions: All instrumentation systems extruded debris. TN was among the groups that produced the lowest amount of apically extruded debris that is clinically acceptable. The amount of apically extruded debris using the TN system was equal to 2 popular systems and statistically significantly less than 2 other popular systems studied.