Effect of combining three precious alloys on dissolution and cell viability using the dynamic extraction technique

Abstract

We examined the effect on dissolution and cell viability of dynamic extraction with similar and dissimilar combinations of type 3 gold alloy (AU), gold-silver-palladium alloy (PD), and silver-indium alloy (AG). Of the six constituent elements that we measured in the alloys, Cu and Zn were selectively dissolved from the materials containing AU and/or PD. They were found in filtrates in the same amount as in extracts. A slight amount of gold and palladium was detected only in the extracts. However, silver and indium were mainly detected in extracts of combinations of AG. They were not found in the filtrates. For the similar and dissimilar combinations of AU and PD, there were only slight differences in cell viability between the extracts and filtrates. Cell viability of extracts was lower in the dissimilar combination of AG than in the similar combinations of AG. Moreover, filtrates exerted less effect on cell viability than did the extracts. The increased dissolution associated with an increase in extraction time further depressed cell viability. These findings indicate that dynamic contact between two alloys may affect dissolution and cytotoxicity of metallic biomaterials used in stress-bearing restorations.