Effect of aging on surface roughness and color stability of resin composites with color adjustment potential

Aim: This study aimed to evaluate the effect of six-month water aging on surface roughness and color stability of resin composites with color adjustment potential. Methods: Disc specimens from Omnichroma (OMNI), Vittra Unique (UNI), Harmonize (HAR), Filtek Universal (FIL), and Filtek Z350XT (Z350) (n=5) were prepared and immersed in water. Color was assessed at baseline, 7 days, 1, 2, 3, and 6 months. CIEDE2000 color differences were calculated between baseline and each time point. Surface roughness was measured at baseline and 6 months. One-way ANOVA with Tukey’s post-hoc test analyzed differences among the composites, while repeated measures ANOVA with Bonferroni’s post-hoc test evaluated differences over time. Color differences were interpreted based on perceptibility and acceptability thresholds, and roughness based on the plaque retention threshold. Pearson correlation assessed the relationship between ΔE00 and surface roughness. Results: Water aging significantly affected CIELab color coordinates for all composites except HAR. All composites exhibited color differences within the acceptable threshold for three months. After 6 months, surface roughness was different among the resins (p = 0.043), only the FIL maintained mean values below Ra=0.2μm. Over the 6-month evaluation period, no correlation between color difference and surface roughness (R=0.057, P=0.788) was demonstrated. Conclusions: All resin composites presented color stability for three months. However, after six months, color changes for Filtek Universal and Vittra Unique were above the acceptability threshold, demonstrating moderately unacceptable discoloration. Surface roughness was affected by six months of water aging, exceeding the plaque retention threshold for all resin composites except Filtek Universal.