Bonding of hybrid composite resin to the surface of gold–alloy used in porcelain‐fused‐to‐metal restorations

Abstract

The aim of this study was to determine the bond strength of hybrid composite resin to the surface of a gold alloy used in porcelain-fused-tometal restorations. The surface of the gold alloy was either ground with a sintered diamond burr, sandblasted with AI2O4 or ground with a siliconcarbide stone. The com^posite resin was bonded to the surface of the gold alloy with or without a commercial silane primer. Bond strength was tested with a three-point loading test, and the elemental composition of the surface of the gold alloy after various mechanical treatments was analysed hy SEM/EDS method. Replicas of the fracture surface of the test specimens were examined by SEM to determine whether or not composite resin particles left on the surface had adhered after the loading test. The results showed that mechanical treatment of the surface of the gold alloy affects the hond strength of the composite resin (P< 0-001) hut that silane treatment of the surface did not affect the bond strength (P = 0-217). SEM/EDS analysis showed evenly distributed aluminium on the surface of sandblasted gold alloy and silicon on the surface that had been ground with the silicon-carbide stone. This study suggests that sandblasting of the gold alloy surface considerably enhances the strength of its bond to hybrid composite resin.