Color alterations of a PMMA resin for fixed interim prostheses reinforced with silica nanoparticles

PURPOSE: The aim of the present study was to evaluate the color changes of an autopolymerizing PMMA resin used for interim fixed restorations, reinforced with SiO(2) nanoparticles. MATERIALS AND METHODS: Silica nanoparticles were blended with the PMMA resin powder through high-energy ball milling. Four shades of PMMA resin were used (A3, B3, C3, D3) and total color differences were calculated through the equations ΔE(ab)= [(ΔL(*))(2) + (Δa(*))(2) + (Δb(*))(2)](½) and [Formula: see text]. Statistically significant differences between ΔE(ab) and the clinically acceptable values of 3.3 and 2.7 and those between ΔE(00) and the clinically acceptable value of 1.8 were evaluated with one sample t-test (P<.05). Differences among the different shades were assessed through One-Way ANOVA and Bonferroni multiple comparison tests. RESULTS: Significantly lower values were detected for all groups concerning ΔE(ab) compared to the intraorally clinical acceptable values of 3.3 and 2.7. Significantly lower mean values were detected for groups B3, C3, and D3, concerning ΔE(00) compared to the intraorally clinical acceptant value of 1.8. Color pigments in red-brown (A3) and red-grey (D3) shades affect the total color change to a greater extent after the reinforcement with SiO(2) nanoparticles compared to the red-yellow (B3) shade. CONCLUSION: Within the limitations of this in vitro study, it can be suggested that reinforcing PMMA with SiO(2) nanoparticles at 0.25 wt% slightly affects the optical properties of the PMMA resin without being clinically perceivable.