Comparative evaluation of the shaping ability and cyclic fatique resistance of new generation nickel-titanium rotary file systems manufactured by different manufacturing processes

In recent years, M-wire, R-phase wire and CM-wire manufactured by applying different thermal proccesses to nickel-titanium alloys lead to utilizing new generation rotary files. Clinical performance of these files is still being investigated. The aim of this in-vitro study is comparative evaluation of the shaping ability and cyclic fatique resistance of six different rotary file systems manufactured from M-wire (Reciproc, ProtaperNext, ProfileVortex), R-phase wire (K3XF, Twisted File Adaptive) ve CM- wire (Hyflex). In the first stage of the study evaluating shaping ability, 90 L-shaped canals in resin blocks with 45° curvatures were included. Blocks were divided into six equal groups (n=15). Pre-instrumentation images of the simulated canals were recorded with stereomicroscope. Pre and post instrumentation images were superimposed with a digital software. Measurements were achieved on these superimposed images with a digital software. In the cyclic fatique resistance evaluation stage of the study, custom made stainless steel canals with 60° angle of curvature and a 3-mm radius were included. Static cyclic fatique resistance of 15 new files were tested in each group. Statistical analyze of the data was performed with one way analysis of variance and post-hoc LSD tests. The Reciproc system resulted in the most apical material removal and canal transportation (p<0.001). The amount of apical transportation was similar for other groups (p>0.05). The least amount of material removal was observed with TFa system in apical one-third and Hyflex in middle and coronal one-thirds. The least time consuming system was Reciproc while the most one was ProfileVortex (p<0.05). No fracture was occurred during preparation. Reciproc and Hyflex groups showed significantly more resistance to cyclic fatigue in all other groups (p<0.001).