Ion release from experimental Au-Pt-based metal-ceramic alloys

The aim of the study was to assess the effect of individual metallic elements within experimental Au-Pt-based dental alloys for porcelain veneering on ion release.

A binary Au-10at% Pt alloy (AP10) was designed as a parent alloy. Six ternary AP10-X (X=In/Fe/Sn/Zn) and four quaternary (AP10-In2)-Y (Y=Fe/Sn/Zn) alloys containing oxide-forming elements, X and Y, up to 2at% were prepared and ion release from the experimental alloys in deionized water and commercial soft drink was examined. For ion release determination samples with size 10 mm x 10 mm x 0.5mm were immersed in 20 ml of deionized water for 5 min. Samples were then removed and immersed in 20 ml of Sprite Light for a further 5 min, and 2h at 37 degrees C. The amounts of ions released in the test solutions were analyzed by inductively coupled plasma-mass spectrometry.

When looking at individual elemental ion release, the order of the amount of dissolved ions was Fe>Zn>In>Sn. Among the base metal elements examined, Fe showed significantly higher levels of ion release than the other base metal elements for all three testing conditions (P<0.05). When looking at the effects of test solution on ion release from the alloys, Sprite Light caused significantly higher level of ion release than deionized water, with the exception of In in the ternary AP10-In1.0 and AP10-In1.7 alloys and the quaternary (AP10-In2)-Sn1.0 alloy, which showed similar or slightly greater amounts of ion release into deionized water.

Significant ion release was only observed from the Fe element. Sn and In elements showed less ion release than the Fe and Zn elements. Accordingly, Sn and In elements should be recommended as oxide-forming elements in Au-Pt-based metal-ceramic systems.