Bond strength of luting cements to core foundation materials.

PURPOSE

The purpose was to compare the shear bond strength of luting cements to foundation materials and to determine the effect of storage in lactate buffer solution.

MATERIALS AND METHODS

Disks that were 8 mm in diameter and 2-mm thick were fabricated from foundation substrates: amalgam, composite resin, resin-modified glass ionomer, and glass ionomer (n = 20). Cylinders that were 2 mm in diameter and 4 mm in length of resin luting cement, resin-modified glass ionomer luting cement, and a glass ionomer luting cement were bonded to the foundation substrate materials. Shear bond strength of each foundation substrate material/cement pair was determined with a universal testing machine after 24 hours. A second set of specimens was tested after storage in a 0.01M lactate buffer solution for 24 hours. A three-way analysis of variance followed by pair-wise comparisons was performed to compare bond strengths (P < .05).

RESULTS

The resin cement provided the highest (P < .05) bond strengths to amalgam, composite resin, and resin-modified glass ionomer foundation materials while the glass ionomer cement showed the lowest bond strength (P < .05) to composite resin and glass ionomer foundation restoration materials. After immersion in a 0.01M lactate buffer solution, the shear bond strength of all the material combinations was significantly lower (P < .05) than nonimmersed specimens, except the bonds between composite resin foundation and resin luting cement, which significantly increased (P < .05) in strength.

CONCLUSION

The resin cement had the highest bond strength to most foundation substrates investigated. The highest bond was observed between the composite resin foundation and resin cement. This bond was also the most durable on immersion in lactic acid.