A comparative evaluation of cyclic fatigue resistance and separated tip length of reciprocating versus continuous endodontic file systems: An in vitro study

Abstract Introduction: Nickel-titanium files are widely used in endodontics due to their clinical effectiveness. Their application may mitigate risk, enhance precision, and conserve time during root canal therapy. The impact of continuous or reciprocating motion on the cyclic fatigue of many emerging file systems remains ambiguous. Therefore, this study aimed to compare the cyclic fatigue resistance and separated tip length between two continuous motion file systems and two reciprocating systems. Materials and Methods: A total of 48 files from 4 different systems; R-Motion reciprocating system 25/0.06, WaveOne Gold reciprocating system 25/0.07, TruNatomy continuous system 26/0.04, and Protaper Ultimate continuous system 25/0.008 were studied, each system contained 12 files. The experiment was performed in metal jig that resembled an artificial canal with a 60° angle of curvature, a 5 mm radius of curvature, a length of 19 mm, and an inner diameter of 1.4 mm. All files were engaged and rotated until the time of the fracture. Data were statistically analyzed and P < 0.05 was considered significant. Results: The mean value values of the R-Motion file (683.2566.25 s) differed significantly from those of TruNatomy and Pro Taper Ultimate ( P < 0.001). WaveOne Gold had no significant difference from the R-Motion file ( P = 0.215) despite R-Motion file having a longer separation time (683.25 s vs. 478.92 s). The mean value of the separated tip length was observed to be 3.84 ± 0.38 mm for R-motion and it was significantly different from the other files except for TruNatomy ( P = 0.001). Conclusion: Within the limitations of the study, it was observed that a reciprocating system R-motion had better cyclic fatigue resistance compared to other file systems.