Galvanic Corrosion of Dental Alloys and Amalgam in Artificial Saliva Containing Citric Acid

Abstract

In this work galvanic corrosion potentials and currents were measured usingpolarization curves of some dental alloys (amalgam, Co-Cr-Mo, Ni-Cr-Mo, SS 316L, Ti-6Al-4V alloys) in artificial saliva containing citric acid with three concentrations 3,6 and9 g/l at 37oC. All galvanic corrosion data were measured to coupling of amalgam andother alloys to investigate the galvanic corrosion between filling and other dental devicessuch as partial-denture framework, crowns, bridges, and endodontic instruments.The results of galvanic corrosion show that the coupling between amalgam and Ni-Cr-Mo alloy gives higher galvanic corrosion current than other metallic contact, and thenthe contact between amalgam and Co-Cr-Mo alloy was heavier compared with couplingof SS 316L and Ti-6Al-4V alloy with amalgam. The increasing of corrosion for alloyscontaining chromium due to rapidly converting of Cr6+ to Cr3+ and this phenomenondecreases the concentration of chromium ions at surface and then increases thedissolution of metal atoms, while decreasing of galvanic corrosion of Ti-alloy coupledwith amalgam due to the passive oxide surface layer (TiO2).

Keywords

• amalgam
• dental alloys
• citric acid
• galvanic corrosion in saliva