Comparison of the Cyclic Fatigue Resistance of Reciproc and Reciproc Blue Nickel-Titanium Instruments in Artificial Canals with Single and Double (S-shaped) Curvatures

Abstract

Objective The aim of this study was to compare the cyclic fatigue resistance of Reciproc (VDW, Munich, Germany) and Reciproc Blue (VDW) in artificial canals with both single and double (s-shaped) curvatures. Methods In total, 80 instruments were tested in this study. Reciproc R40 and Reciproc Blue R40 instruments were selected for the cyclic fatigue resistance test (n=20 in each test). Each instrument was rotated in canals with a single curvature (60° curvature, 5-mm radius) and a double curvature (first coronal curve: 60° curvature and 5-mm radius; second apical curve: 70° and 2-mm radius) until fracture. The time to fracture was calculated, and the length of each fractured fragment was recorded. A one-way analysis of variance (ANOVA) and Tukey's post hoc tests were used to analyse the time to failure. Results All the instruments had significantly higher fatigue resistance in the single simulated curvature canal than in the double curvature canal (P 0.05). Conclusion The Reciproc Blue instruments showed higher cyclic fatigue resistance than the Reciproc instruments in both single and double canal curvatures.