Ceramic bonding to a dental gold-titanium alloy

Investigations of the metal-ceramic bonding of the alloy Au98.2Ti1.7Ir0.1 (wt) in comparison with a well-approved traditional Au-Pt-Pd-based alloy were performed, Bond strength of both alloys, measured with a three-point flexure bond test, was in the same order of magnitude. Failure mode was different for both alloys. Failure of the bonding of the Au-Ti-Ir alloy predominantly occurred at the alloy-oxide interface. On the Au-Pt-Pd alloy more ceramic residues were observed. Sandblasting the metal surface with alumina increases the roughness of the surface, but only slightly increases the bond strength, independent of the grain size of the alumina. Immersion in a corrosive solution of sodium chloride and lactic acid reduced the bond strength of both alloys by about 35%. While this decrease for the Au-Pt-Pd alloy occurred after an immersion time of only two days, it took about 35 days for the Au-Ti alloy. The results indicate that the alloy Au98.2Ti1.7Ir0.1 (wt) provides sufficient ceramic adherence. The results also proved that the three-point flexure bond test used is a sensitive method for measuring metal-ceramic bond strength, thus supporting the decision to integrate this test within the international standard ISO 9693. (C) 2002 Elsevier Science Ltd. All rights reserved.