Shear testing of the porcelain-metal bond.

A simple shear test was employed to determine the bonding strength of porcelain to a gold metal substrate and to a non-precious metal substrate after they had been aged in double-distilled water at 37 degrees C for four and 12 months. A 7.4% and 18.1% decrease in bond strength after four months and 12 months, respectively, was observed for the porcelain-gold system, and a decrease of 21.2% and 21.4% after four and 12 months, respectively, for the non-precious-porcelain system. A significant difference was observed between the bond strengths of the porcelain-metal composites: 51.17 +/- 11.29 MPa for the porcelain-gold system and 31.83 +/- 3.65 MPa for the porcelain-non-precious system.