ABSTRACT
The application of [Molloplast-B] which is a heat-cured silicone base material used for resilient layer dentures was evaluated. Its bond strength to both heat and cold cured polymethyl methacrylate resins was tested through tensile and shear bond strength tests. The effect of water immersion on this bond strength after two days, one month and three months was studied, also SEM study for the nature of surface interface between the material and both heat and cold PMMA resins at different stages of measurements was carried on. The results of this investigation showed both clinical and technical satisfactory bond strength between the material and the different dentures bases used in the study, while dramatic reduction of bond strength values was observed especially after three months immersion in water due to absorption of water by the resilient material resulting in "adhesive failure". The absorbed water had its effect through: direct percolation into the bond site and through changing the viscoelastic properties of the [Molloplast-B] itself. These findings were supported by the results obtained from the scanning electron microscopic study