Comparing the cyclic fatigue resistances of Reciproc Blue and Rotate instruments in simulated severe apical curvature

Purpose: This study primarily aims to evaluate the cyclic fatigue resistance of Reciproc Blue (VDW, Munich, Germany) and Rotate (VDW, Munich, Germany) instruments by testing them in a severe apical curvature at intracanal temperature.
Methods: In total, 12 Reciproc Blue (25.08) and Rotate (25.06) instruments were tested in a cyclic fatigue device at intracanal temperature (37°C). The instruments were tested in a stainless steel block with an artificial canal with a curvature angle of 90° and a radius of curvature of 2 mm. The instruments were operated until fracture occurred; then, the time for fracture (TF) was calculated. The length of the fractured tips was measured using a digital caliper. The data were analyzed using Student’s t-tests, with significance level set at p< 0.05.
Results: The TF values of Reciproc Blue (450.60 ± 34.36 s) were found to be significantly higher than Rotate (315.70 ± 70.89 s) (p< 0.05). Moreover, no significant difference was observed between the instruments as regards the length of the fractured fragments [Reciproc Blue: 3.11 ± 0.25 mm, Rotate: 2.97 ± 0.27 mm, (p> 0.05)].
Conclusion: Reciproc Blue displayed significantly higher cyclic fatigue resistance values than Rotate files when tested in the artificial canal with acute apical curvature.