Comparison of cyclic fatigue resistance of THREE different reciprocating nickel titanium file systems

Comparison of Cyclic Fatigue Resistance of Three Different Reciprocating Nickel Titanium File Systems Aim: The aim of this study was to evaluate the cyclic fatigue resistance of three different heat-treated reciprocally moving NiTi files under different conditions. Matherial & Methods: Three different file systems were used to prepare the root canals. In Group 1 (n=30), dynamic cyclic fatigue (DCF) test was performed after the preparation of mesiobuccal root canal of 3 maxillary molars and sterilization procedure. In Group 2 (n=30), DCF test was performed after each canal file was kept in 3% sodium hypochlorite (NaOCl) solution for 15 minutes and sterilization was applied. Group 3 (n=30) was the control group and DCF test was performed without any procedure on the files. The Shapiro-Wilk test was used to evaluate the normallity and Levene test was used to evaluate the homogeneity of variance. Statistical analysis was made using the Two-Way ANOVA test. For within-group comparisons Bonferroni test was applied. Results: When the time required to fracture (TrF) were evaluated in the Group 1, the T-Endo Must file system showed similar results with the WaveOne Gold file system (p>0.05). The TrF for T-Endo Must file was longer than the One RECI file system (p<0.05). One RECI and WaveOne Gold file systems showed similar results (p>0.05). When the TrF were evaluated in the Group 2, T-Endo Must and WaveOne Gold file systems showed similar results (p>0.05), however, the One RECI file system showed significantly shorter TrF than the other two file systems (p<0.05). In the control group, the T-Endo Must file system showed significantly longer TrF than the other two file systems (p<0.05). The TrF of One RECI and WaveOne Gold file system were similar (p>0.05). The length of broken file fragment of T-Endo Must was significantly longer than other two file systems in Group 2 (p<0.05). Keywords: T-Endo Must, One RECI, WaveOne Gold, cyclic fatigue resistance, reciprocation