Effect of age of sample on the shear bond strength of dentin bonding agents to dentin.

The effect of sample age on the shear bond strengths of two dentin bonding agents to human dentin was evaluated by bonding composite resins to human dentin treated with either Imperva-Bond or Prisma Universal Bond 3. One-half of the specimens were tested at 5 minutes, while the remainder were thermocycled and tested at 2 weeks. Results were analyzed using two sample t tests at the 0.05 probability levels. Failures were evaluated using light microscopy and categorized as adhesive, cohesive within resin, cohesive within tooth, or mixed. The bond strengths were significantly higher for Imperva-Bond than for Prisma Universal Bond 3 at both time periods. For both bonding agents, the 2 week bond strengths were significantly higher than the 5 minute bond strengths. The 2 week bond strength of Imperva-Bond approaches that of unfilled resin to etched enamel.