New Solubility Test by Sliding on Ag-Pd-Cu-Au Alloys with Different Cu Contents into Different Solutions with or Without Mucin

Aims: The aims of this study was designed to analyze the released ions from Ag-Pd-Cu-Au alloys after a new sliding solubility test in different solutions with or without mucin. Materials and methods: Eluate solutions, similar to Fusayama’s artificial saliva, Hanks buffer solution, and artificial saliva with or without mucin were prepared. Ag-Pd-Cu-Au casting alloys were selected by particularly examining Cu of 0–20 wt%. The casting specimen surface was rubbed with zirconia balls in the eluate solutions using a seesaw movement for five minutes every hour for 7 days at 37°C. The amounts of ions were detected using inductively coupled plasma mass spectroscope (ICPMS). Data were analyzed using one-way repeated analysis of variance (ANOVA) and Tukey’s multiple comparisons (=0.05). Results: According to the addition of mucin to the solutions, amounts of elute Cu ions increased in higher Cu content alloys. Similarly, the elution of Zn ions was found to be increasing, with minor exceptions, among the alloys. As for the Pd ion elution, it was interesting that the amount of Pd ions decreased, with the exception for some eluate solutions. The dissolution of In ions can be expected to progress rapidly. The behavior of the released Ag ions was complex because it differed according to either the alloy or the elute solution, or both. Conclusions: For higher Cu content alloys, amounts of elute Cu ions increased in the elute solutions with mucin. In contrast, amounts of other metallic ions increased and decreased or showed no change depending on the test conditions. The differences of alloy components and elute solutions might be affected by the amounts of elute ions in this sliding solubility test. Not until the elute conditions were the same did the values for ion concentrations compare with conventional reported values.