Cyclic and Torsional Fatigue Resistance of Reciprocating Single Files Manufactured by Different Nickel-titanium Alloys

Abstract Introduction The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the following reciprocating single-file systems: ProDesign R 25.06 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), Reciproc R25 (VDW GmbH, Munich, Germany), and Unicone L25 (Medin SA, Nové Město in Moravě, Czech Republic). Methods Sixty instruments of the ProDesign R, Reciproc R25, and Unicone L25 systems ( n = 20) were used. Cyclic fatigue resistance was tested measuring the time to failure in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature ( n = 10). Torque and angle of rotation at failure of new instruments ( n = 10) in the 3 mm from the tip portion were measured during torsional testing according to ISO 3630-1. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using 1-way analysis of variance and Tukey tests, and the level of significance was set at 5%. Results The cyclic fatigue resistance values of ProDesign R 25.06 were significantly higher than the other groups ( P