Evaluation of cyclic fatigue of three different Rotary Nickel Titanium Systems

Abstract

To overcome the inconveniences of manual filing systems, nickel-titanium (NiTi) rotary shaping techniques were developed. The study was conducted to evaluate the cyclic fatigue resistance and martensitic/austenitic phase at body and room temperatures for HyFlex EDM, M-Pro, Denjoy i3Gold files.Twenty files of each system were used. Ten of them were used at room temperature and ten were used at body temperature. Dynamic cyclic fatigue testing was performed with a specific device, which allowed the instruments to rotate freely inside a Stainless-Steel artificial canal while providing an axial movement with amplitude of 3mm up and down movement. The number of cycles to failure (NCF) was calculated. A Sample with weight 10 to 15 gm of each instrument was evaluated using DSC. The DSC analyses were conducted over a temperature ranging from 0o C to 60o C.The results showed higher cyclic fatigue of HyFlex EDM followed by Denjoy i3Gold and M-Pro showed the lowest values for both room and body temperatures. Temperature showed no effect on cyclic fatigue for all instruments within this study. The differential scanning calorimetry confirmed the presence of the martensitic phase in Hyflex EDM, M-Pro and Denjoy i3Gold at room temperature and body temperature.