Resistencia a la fatiga cíclica de dos sistemas rotatorios de níquel-titanio con distintas tecnologías de tratamiento térmico: S-One y 2Shape

Abstract

Introduction: The aim of this in vitro study was to evaluate the cyclic fatigue resistance of two nickel-titanium (NiTi) rotary file systems: S-One (Fanta Dental, Shanghai, China) and 2Shape (MicroMega, Besançon, France). A total of 40 files were randomly assigned to two experimental groups (n = 20): Group 1 included S-One 25/.06 NiTi files, and Group 2 included 2Shape 25/.06 NiTi files.

Metodology: All instruments were tested using a custom-made metallic device featuring an artificial canal with a 90° curvature and a 3 mm radius. Files were operated in continuous rotation according to the manufacturers’ recommended settings until fracture occurred. The number of cycles to failure (NCF) was determined using a digital timer and confirmed via video recording.Normality of the data was assessed using the Shapiro-Wilk and Kolmogorov-Smirnov tests. Statistical differences in NCF between groups were analyzed using Student’s t-test, while the Kruskal-Wallis test was used to compare differences in fracture fragment lengths (p<0.05).

Results: The results showed that the S-One file system exhibited significantly greater cyclic fatigue resistance compared to the 2Shape system. Additionally, fractures in the S-One files resulted in longer fragment lengths, suggesting a different failure behavior between the two systems.

Conclusion: The S-One files showed higher cyclic fatigue resistance than 2Shape.