Laboratory evaluation of a heat cured silicone base material used for resilient layer dentures

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, a 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 this 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

Studying the parotid salvary flow rate during the climacteric period of life utilizing different denture base materials

During the climacteric period of life, complex changes take place. One of the body functions that could be affected and might affect denture retention and tissue tolerance is the salivary flow rate. In this study the parotid salivary flow rate [PSFR] was recorded in edentulous menopausal females and compared with that of non-menopausal and non-lactating females. In the meantime, the effect of acrylic versus metallic dentures on the PSFR in menopausal females was detected. The results revealed that the PSFR in non-menopausal was higher than that of menopausal females. In the meantime, for both types of dentures immediately after denture insertion the PSFR was increased but returned to its original level after one month of denture being in use. Moreover, there was no difference between acrylic and metallic denture base materials regarding the affection on the PSFR