Pedulla E, et al. - Researchers evaluated the effects of sodium hypochlorite (NaOCl) immersion and sterilization on the cyclic fatigue resistance of heat-treated nickel-titanium (NiTi) rotary instruments. Except for Twisted Files, repeated cycles of sterilization did not influence the cyclic fatigue of NiTi files, which showed a significant decrease of flexural resistance after 3 cycles of sterilization. As per the outcomes, immersion in NaOCl did not reduce significantly the cyclic fatigue resistance of all heat-treated NiTi files tested.