Tezer, Emine Odabaşı2022-10-242022-10-242022https://doi.org/10.52037/eads.2022.0003http://hdl.handle.net/20.500.12575/84787Purpose:To compare the cyclic fatigue resistance of ProTaper Universal (PTU) and ProTaper Gold (PTG) nickel titanium files at different angles and to examine the fractured surface areas by using scanning electron microscope (SEM). Materials and Methods: A special static test device made of stainless steel with artificial canals at 3 different angles. The files were rotated until they were broken in artificial canals with 45°, 60° and 90° angles and also the time was recorded using a digital stopwatch. The number of cycles to failure was calculated for each instrument. Statistical analyzes were made by using one-way analysis of variance (Anova) for comparison between main groups. Results: PTG files showed higher fatigue resistance (p<0.001) than PTU files in all groups. SEM results displayed similar characteristic structures in pits and fissures caused by fracture due to cyclic fatigue regardless of angle and file type. Conclusion: Although surface properties of broken instruments do not play a decisive role in clinical practice it was observed that heat-treated Ni-Ti files exhibited higher fatigue resistance at all angles compared to conventional files according to the number of cycles during experimental periodenCyclic fatigueFractured instrumentProTaper GoldArticle49110142757-6744