THE EFFECT OF METAL-SURFACE TREATMENT ON THE SHEAR BOND STRENGTHS OF BASE AND NOBLE-METALS BONDED TO ENAMEL

Adhesive resin luting agents provide a way for bonding metal surfaces to teeth through a combination of micromechanical retention to the rou gh metal surface and chemical adherence to metal oxides. The purpose o f this study was to measure the effect of metal alloy surface treatmen ts that would produce different textures and oxide layers on the shear bond strength of three alloys luted to etched enamel with one adhesiv e resin luting agent (Panavia). After a simulated porcelain firing seq uence, high noble (Olympia), noble (Jelstar), and base metal (Rexilliu m III) alloy specimens were subjected to one of the following treatmen ts: (1) sandblasting and simulated glazing, (2) simulated glazing only , (3) simulated glazing and sandblasting or (4) simulated glazing, san dblasting, and tin plating. The specimens were bonded to extracted tee th and subjected to shear testing after water storage for 2 weeks, the rmocycling for 500 cycles, and water storage for an additional 2 weeks . Data were analyzed with a two-way analysis of variance (alpha = 0.05 ). The base metal specimens and the tin-plated high noble and noble me tal specimen groups exhibited similar mean shear bond strengths that w ere greater than the other groups. Those high noble and noble metal al loys sandblasted after simulated porcelain firing cycles and before th e simulated glaze cycle exhibited nonsignificant increases in shear bo nd strengths compared with the groups that were either sandblasted aft er the simulated glaze cycle or not sandblasted at all.