Surface oxide layer formation on Au-Pt-Pd-Si alloys for dental resin restorations

The aim of this study was to develop Au-Pt-Pd-Si alloys with metal-resin bonding properties optimized for dental restorations. The amount of silicon added ranged from 0.00-0.54 wt.% . The Au-Pt-Pd-Si alloys were manufactured using an arc melting furnace. They were homogenized at 800°C in air and cold rolled to a 1 mm thickness. The changes in the surface morphology and oxide layer formation were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy, electron probe microanalysis and X-ray photoelectron spectroscopy before and after oxidation treatment. The mechanical properties of the alloys were evaluated using micro-hardness and shear bonding tests. The surface oxide layer was mostly composed of silicon dioxide and metallic gold. The microhardness of the Au-Pt-Pd-Si alloys increased as a function of the silicon concentration. The shear bonding strength was significantly higher (9.30 MPa) at 0.54 wt.% silicon (p < 0.05).