Influence of pH level of artificial saliva on corrosion behavior and nickel ion release of a Ni-Cr-Mo alloy: an in vitro study

Purpose The purpose of this paper (in vitro) study was to determine the effect of pH of artificial saliva on the corrosion behavior of a Ni-Cr-Mo alloy at 37 +/- 1 degrees C. Design/methodology/approach The corrosion behavior of a commercially available Ni-Cr-Mo base dental alloy was studied by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The effect of pH on corrosion and Ni ion release was also investigated by scanning electron microscopy and atomic absorption spectroscopy. Findings The results suggested that the order of corrosion rate was: pH3 > pH5 > pH9 > pH7. Corrosion rate in pH3 was significantly different with other pH levels. Nickel depletion significantly occurred in alloy without passivation. The corrosion resistance and ion release of Ni-Cr-Mo alloys in different pH levels of artificial saliva depended on the stability of the passive layer. Acidic pH level severely corrodes Ni-Cr-Mo base metal alloys and increases Ni ion release. Originality/value This manuscript describes the relationship between corrosion rate and nickel ion release of a dental Ni-Cr-Mo base alloy as a function of saliva pH examined by electrochemical impedance spectroscopy (EIS), polarization, scanning electron microscopy and energy dispersive X-ray spectroscopy in artificial saliva. The main novelty of this work includes the material/structure/corrosion relationship in artificial saliva with different pH. This property would be very interesting for dental materials applications and clinical dentistry.