Effects of Different Inorganic Fillers on Mechanical Properties and Degree of Conversion of Dental Resin Composites

The aim of the study was to evaluate the influence of different fillers on the chosen functional properties of experimental composites based on typical polymeric matrix, in order to understand the effect of different fillers on their properties and to develop a simple base composite for further investigations with experimental fillers, e.g. with antimicrobial properties. Previous experiments have been usually based on commercially available composites of unknown composition or compilation of monomers, without reinforcing fillers. Scanning electron microscopy was used to investigate the quality of fillers’ dispersion, which was satisfying. Results showed significant differences between materials’ diametral tensile strength (p = 0.0019), compressive strength (p < 0.0001), Vickers microhardness (p < 0.0001), flexural modules (p = 0.0018), and the degree of conversion (p < 0.0001), but flexural strength was not significantly different (p = 0.0583). Investigations indicated that no filler type had an especially positive impact on the mechanical properties, but reinforcement effect was achieved by proper compilation of silica nanofiller and variable glass fillers. Nanofiller decreased the degree of conversion.