Comparison of cyclic fatigue properties of four nickel-titanium single-file systems in curved artificial canals

Abstract Backgrounds Nickel-titanium (NiTi) rotary instruments are widely used in endodontics because of their flexibility and superelasticity. However, the cyclic fatigue resistance of ORODEKA and M3-L systems in curved canals remains unclear. This study aimed to evaluate and compare the cyclic fatigue resistance of four single-file NiTi systems: Reciproc Blue (REC), ORODEKA ONEPLEX (ORO), M3-L 2018 (M3L), and TruNatomy (TRU)—in artificial root canals with varying curvature angles (45°, 60°, and S-shaped). Understanding their performance under mechanical stress can help clinicians select appropriate instrument for complex root canal anatomies. Materials and methods four single-file systems were tested in static simulated canals with 45°, 60°, and S-shaped curvatures. The instruments were rotated at manufacturer-recommended speeds until fracture using a customized cyclic fatigue testing device. The number of cycles to failure (NCF) was recorded for each instrument. one-way analysis of variance (ANOVA) and Tukey’s honestly significant difference (HSD)(post-hoc test) were used for statistical comparisons. Results TruNatomy (TRU) exhibited significantly higher NCF values across all canal models compared with the other systems (p < 0.05). Reciproc Blue (REC) demonstrated superior performance over ORODEKA (ORO) and M3-L (M3L), particularly in the 60° subgroup, where no significant difference was observed between REC and TRU (p > 0.05). This study provides a comparative analysis of the cyclic fatigue resistance of four single-file systems. TruNatomy demonstrated a significantly higher fatigue resistance than the other three systems, highlighting its superior performance in curved canals. Conclusions These findings suggest that TruNatomy is a reliable option for managing complex root canal anatomies. However, further research is required to investigate additional factors influencing the mechanical behavior of NiTi instruments and to optimize their clinical application in endodontic practice.