Effect of adhesives on bond strength of porcelain veneer to base metal alloy

Objective: The purpose of this in vitro study was to evaluate the bond strength of porcelain veneer to base metal alloy using different adhesive systems. Method and materials: Eighty cylindrical models were cast in a nickel-chromium-beryllium base metal alloy. After they were mounted in self-cured acrylic resin, the surfaces of the specimens were air abraded. Specimens were divided into four groups of 20. Control porcelain disks were baked on the base metal. For the experimental groups, 60 porcelain disks were made. After 50-µm aluminum oxide sandblasting, a silane coupling agent was applied to the surface of the porcelain. The experimental groups were based on the type of adhesive used to bond porcelain to metal: Scotchbond Multipurpose and Duo Cement; One Coat Bond and Duo Cement; or Panavia 21 Ex. After 500 thermal cycles, the bonded porcelain specimens were placed under a continuous shear load of 2 mm/min until fracture occurred. Results: Mean values for bond strength were 25.39 (control), 19.10 (Panavia 21 Ex), 15.81 (Scotchbond Multipurpose), and 13.69 MPa (One Coat Bond). Statistically significant differences in bond strength were noted between the control group and all the experimental groups. A statistically significant difference was observed between Panavia 21 Ex specimens and One Coat Bond specimens. Conclusion: Panavia 21 Ex provided an effective bond strength between a porcelain veneer and a base metal alloy, the closest of all the experimental groups to that of the control group.