Three polishing techniques for composite restoration were compared for the resultant surface roughness, reduction rate and discoloration using a light-cured microfilled composite and a self-cured hybrid filled composite. Both the resultant roughness and reduction rate were smallest with Silicone Point White, and followed with Silicone Point Green and Silicone Point Brown fn order glossy surface of composite polymerized under a matrix considerably discolored regardless of the extreme smoothness. Discoloration decreased when the surface was reduced by polis17ng and it was smallest with Silicone Point White and followed with Silicone Point Green and Silicone Point Brown in order. Although the resultant roughness comparable, between the two types of composite, the reduction rate and discoloration were significantly greater with the light-cured microfilled composite than the self-cured hybrid filled composite.
This study was conducted to observe the polymerization shrinkage and tensile strength of the polyfunctional based composites containing various types of diluent monomer systems at several concentrations. Fifteen matrix-monomers systems were prepared and four experimental polyfunctional composites were made by filling a hybrid filler with a constant weight of 86.5 %. The rate of polymerization shrinkage was calculated by the specific gravity of the monomer and the polymer by using a picnometer and Hubbard type hydrometer. Tensile strength was measured by using an Instron Universal Testing Machine. The results of this study indicated that polymerization shrinkage of unfilled polyfunctional resin ranged from a volume percentage of 3.88 to 8.56 and the tensile strength of the unfilled polyfunctional resin showed more significant results than Bis-GMA unfilled resin. The volume percentage of polymerization shrinkage of the filled resin ranged from 1.23 to 1.89; the best and most significant value was obtained from the polyfunctional monomer diluted with Bis-MPEPP 2.6E. Tensile strength of the filled polyfunctional experimental resin ranged from 71.58 to 80.92 MPa, which indicates that M-4 resin showed significantly higher tensile strength compared to the M-6 resin formulation.