Cyclic Fatigue Resistance of VDW.ROTATE and Reciproc Blue Nickel-titanium Files at Root Canal Temperature

Background. The aim of this study was to compare the VDW.ROTATE instruments with the Reciproc Blue instruments in different kinematics in terms of the cyclic fatigue (CF) resistance. Methods. A total of 60 instruments, 40 VDW.ROTATE and 20 Reciproc Blue instruments, were divided into 3 groups (20 files each): VDW.ROTATE were used in both continuous rotation and reciprocating motions; and Reciproc Blue were used in only reciprocating motion. CF resistance was tested in stainless steel curved canals (60°, r = 3 mm) at an intracanal temperature of 35° ± 2°C until fracture, and the time to fracture was recorded in seconds. The data were analysed statistically using Kruskal–Wallis and Tamhane’s T2 tests (P < 0.05). Results. All reciprocating motion groups resulted in a longer mean duration to failure compared with the continuous rotation motion group (P < 0.05). Conclusion. It was observed that the Reciproc Blue instruments had higher cyclic fatigue resistance than VDW.ROTATE instruments (P<0.05). In recent studies, it is known that reciprocal movement increases cyclic fatigue resistance compared to rotational movement. The VDW.ROTATE instrument, which has a similar size, design and alloy as the Reciproc Blue instrument, can also be used by clinicians in reciprocating motion with endomotors capable of reciprocating in different directions. However, even if the cyclic fatigue resistance is increased by using VDW.ROTATE instruments in reciprocation, the cyclic fatigue resistance is lower compared to Reciproc Blue instruments.