Effect of ageing on the bond strength of a permanent denture soft lining material.

Molloplast-B is a widely used, long-term, heat-cured silicone denture soft lining material. Adhesion failure of this material to poly (methyl methacrylate) denture base material is a problem that is encountered clinically. The purpose of this study was to investigate the effects of long-term immersion in water at 37 +/- 1 degrees C and of accelerated ageing in water at 50 +/- 1 degrees C on the tensile and shear bond strength values of this denture resilient lining material bonded to a heat-cured denture base material. Immersion in water for 1 week at 37 +/- 1 degrees C had no significant effect on the measured bond strength values. Longer immersion of specimens in water at 37 +/- 1 degrees C led to a significant reduction in the measured tensile and shear bond strengths. The present study has demonstrated that the reduction in Molloplast-B bond strength that occurs as a result of long-term ageing in water at 37 +/- 1 degrees C can be achieved in a shorter period of time by ageing the specimens in water at a higher temperature.