Bond strength of composite resin to porcelain with newer generation porcelain repair systems.

A laboratory study was conducted to evaluate the mean shear bond strength of composite resin bonded to porcelain with the use of eight newer generation repair systems. The range of shear bond strength after 24 hours of water storage was 23.5 +/- 5.3 MPa to 12.0 +/- 2.3 MPa. After 3 months of water storage and thermocycling, the bond strength range was 20.7 +/- 1.7 MPa to 4.2 +/- 1.0 MPa. Three of eight systems evaluated did not exhibit a significant (p > 0.05) decrease in bond strength when the 24-hour bond strengths were compared with the 3-month bond strengths. Most specimens failed cohesively in the porcelain at 24 hours, but at 3 months only four of the eight systems showed consistent failures in the porcelain.