Cyclic Fatigue Resistance and Differential Scanning Calorimetric Analysis of Three Different Nickel-Titanium Rotary File Systems (An In-vitro study)

Abstract

The study was conducted to evaluate the cyclic fatigue resistance and martensitic/austenitic phase at body and room temperatures for HyFlex EDM one, Fanta AF Blue S One, ZB-F6 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. The number of cycles to failure (NCF) was calculated. Representative samples from all the previous groups of files were scanned with SEM to evaluate the mode of fracture. A Sample with a weight of 10 to 15 gm of each instrument was evaluated using DSC. The DSC analyses were conducted over a temperature ranging from -5 C. The results showed higher cyclic fatigue of HyFlex EDM o C to 60 o OneFile followed by AF Blue S One and ZB-F6 showed the lowest results for both room and body temperatures. Temperature showed no effect on cyclic fatigue for both AF Blue S One and Hyflex EDM One instruments while it decreased the cyclic fatigue of ZBF6

instruments. The differential scanning calorimetry confirmed the presence of the martensitic phase in Hyflex EDM One and AF Blue S One at room temperature and body temperature while it showed the presence of austenitic phase in ZB-F6 at body temperature which is responsible for lower cyclic fatigue resistance.