Aim: The aim of this study was to evaluate the cyclic fatigue resistance of Reciproc Blue (VDW, Munich, Germany) and Rotate (VDW, Munich, Germany) by testing in a severe apical curvature at intracanal temperature.
Methodology: Twelve 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 curvature angle of 90° and radius of curvature of 2 mm. The instruments were operated until fracture occurred, then the time for fracture (TF) was calculated. The length of fractured tips was measured with a digital caliper. The data were analyzed using Student’s t-tests with significance level set at P < 0.05.
Results: The TF values Reciproc Blue (450.60 ± 34.36 s) were significantly higher than Rotate (315.70 ± 70.89 s) (P < 0.05). There was no significant difference between the instruments regarding the length of 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