Effect of sterilization treatment on the corrosion behavior of NiTi endodontic instruments

This study investigates the influence of the sterilization treatment conducted at 50 °C in 5% sodium hypochlorite solution (NaClO) on the corrosion behavior of endodontic instruments made of NiTi alloy (GT Rotary and K3) and stainless steel (K File) by measuring potentiodynamic polarization curves in the same environment at 37°C. For the sake of comparison, the electrochemical characterization was also carried out on endodontic instruments that were not sterilized. The characterization of the sample surface after the electrochemical tests were carried out by means of scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX). There was no significant influence of the sterilization treatment on the corrosion behavior of K File and GT Rotary endodontic instruments. On the contrary, a negative influence of the sterilization treatment on the corrosion resistance of K3 endodontic instruments was observed, and the effect appears to be more dramatic for longer treatment periods.