Determination of degree of conversion as a function of depth of a photo-initiated dental restoration composite-II application to commercial SureFil™

In the previous work we evaluated in vitro the degree of conversion (DC) as a function of depth of a photo-initiated dental restoration composite with the trade name Fill Magic™, using FT-IR as the characterization technique. The DC showed a tendency to decrease with increasing depth, attaining values in the range of 40-50% and indicating that a high amount of residual monomer has remained. We stated that several factors, such as monomer viscosity and ratio, size of fillers and great difference in refractive indices of the organic and inorganic constituents, could contribute to decreasing the DC. In this work, we present the results of DC of another commercial composite, Surefil™, polymerized under the same conditions as reported previously. The DC also decreased with increasing depth but reached lower values (40-26%) than the first composite. Through the same ordinary techniques used in the preceding work we found that the composite formulation is 83.3% of inorganic fillers, 15.4% of BisfenolA/dimethacrylate (BisGMA) and 1.3% of triethyleneglycoldimethacrylate (TEGDMA) as monomers. The statistical analysis indicated that the results were significant at the 95% level. Additionally, the observed low DC we mainly attributed to complexity of the filler and low content of BisGMA.