Shear bond strengths of resin luting cements to laboratory-made composite resin veneers.

Retention problems have been reported with the clinical use of indirect microfilled resin veneers. This study used 24-hour shear tests to assess the bond strengths of such a resin veneer compared with other veneer types. The effect of different resin luting cements and resin veneer surface treatments were analyzed to elucidate factors by which retention could be increased. The six resin luting systems investigated showed a range of bond values. Debonding occurred primarily at the veneer/cement interface. G-Cera material produced the weakest bonds to Isosit-N resin. Surface treatment of Isosit-N veneers resulted in bond strength changes. Sandblasting reduced the force required for bond failure; Special Bond resin increased it slightly. Improving retention of prefabricated resin veneers proved difficult. Etched hybrid resin veneers delivered higher bond strengths than micro-filled resin veneers but not significantly. Etched porcelain veneers, however, provided consistently the strongest bond strengths with cohesive, as opposed to adhesive, bond failure.