cyclic fatigue resistance of 2shape, twisted file and endosequence xpress nickel-titanium rotary files at intracanal temperature

Background. the aim of this study was to compare the cyclic fatigue resistance of 2shape, twisted file (tf) and endose-quence xpress (esx) nickel-titanium rotary files at intracanal temperature (35°c). methods. twenty 2shape ts1 (25/.04), 20 tf (25/.04) and 20 esx (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°c). all the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (ncf) for each file was calculated. kruskal-wallis test with bonferroni correction was performed to statistically analyze data using spss 21.0. statistical significance was set at p<0.05. results. ncf values revealed that the 2shape had significantly the highest cyclic fatigue resistance, followed by tf and esx at intracanal temperature (p<0.05). the difference was significant between the tf and esx groups (p<0.05). there was no significant difference among the 2shape, tf and esx files with respect to the lengths of the fractured file fragments (p>0.05). conclusion. within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2shape files at the intracanal temperature is higher than that of tf and esx files.