Influence of different heat treatments on torsional and cyclic fatigue resistance of nickel-titanium rotary files: a comparative study
Protaper Universal (PTU), Protaper Gold (PTG) (Maillefer, Ballaigues, CH), EdgeTaper (ET), and EdgeTaper Platinum (ETP) (Albuquerque, NM, USA) were tested for both torsional and flexural resistance. The aim of the present study was to evaluate the influence of proprietary heat treatment on the metallurgical properties of the aforementioned instruments. Four groups of 30 different instruments (size 20.07) were tested, then divided into two subgroups of 15 instruments-one for the cyclic fatigue test in a curved canal (90°-2 mm radius) at 300 rpm and 2.5 Ncm.