The Effect of Nanofilled Resin-Base Coating on the Mechanical and Physical Properties of Resin Composites

Objective The aim of this study was to evaluate the effects of a nanofilled resin-base coating on the physical and mechanical properties of four different types of resin composites. Materials and Methods Disc-shaped specimens of four resin composites (Aura bulk fil [SDI], IPS Impress Direct [Ivoclar], Filtek Z250, and Filtek P60 [3M/ESPE]) were prepared and divided in two groups: either uncoated or coated with G-coat plus ( n = 10). The specimens were obtained and stored in distilled water (DW) at 37°C. For water sorption and solubility, the specimens were stored for 60 days in DW and measured according to ISO 4049 instructions. The specimens were subjected to color change (ΔE), microhardness, and flexural strength (FS) measurements after 24 hours and 60 days of immersion in DW. Statistical Analysis ANOVA, post hoc Tukey’s, and independent t -tests were used to analyze data. Results Mean solubility values of coated groups were significantly lower than that of uncoated ones ( p < 0.001). No significant differences were detected between neither water sorption nor FS of coated and uncoated groups ( p = 0.502 and p = 0.510, respectively). For all materials except IPS Empress, the mean values for ΔE were not statistically different between coated and uncoated groups, and mean microhardness values of the uncoated groups were significantly greater than the coated groups ( p < 0.001). Conclusion Coating resin composites improved water sorption and solubility but increased ΔE, decreased microhardness, and had no significant effect on FS in the long run.