Bond strength of a resin-based composite to leucite-reinforced ceramic and dentin

Purpose: To compare the in vitro tensile bond strengths of resin-based composite bonded to dentin and to a leucite-reinforced ceramic in an as-received condition (pre-silanated) or re-etched, re-silanated condition. Materials and Methods: Caries-free human molars were ground to expose occlusal, superficial dentin. Dentin surfaces were etched with 37% phosphoric acid and rinsed, leaving a moist dentin surface. Leucite-reinforced ceramic inserts (SONICsys) also were tested as received (pre-etched, pre-silanated) or retreated with hydrofluoric acid and silane. Bonding agent (Syntac Single-Component) was applied in two layers and light cured. An all-purpose resin-based composite (Tetric Ceram) was used to prepare tensile bond strength specimens for the dentin and two ceramic groups. Fourteen specimens were prepared for each group. After 24 hours in distilled water, tensile bond strength (MPa) was measured using a testing machine. Analysis of variance was used to evaluate data. Results: Bond strengths obtained were 10.2 MPa for composite bonded to dentin, 10.5 MPa for composite bonded to as-received ceramic inserts, and 9.6 MPa for composite bonded to retreated ceramic inserts, with no statistical difference between the three groups. Re-treatment of leucite-reinforced inserts did not increase or decrease bond strength to resin-based composite. Also, the bond strength of resin-based composite to dentin was similar to that of the ceramic to composite.