Color stability, surface roughness, and surface morphology of universal composites

This study aimed to evaluate the surface roughness (Ra; µm), color stability (∆E₀₀), and surface morphology of universal composites after exposure to discoloring solutions. 200 composite discs (2 × 10 mm) were prepared using four paste type (Estelite Asteria, G-aenial A'chord, Filtek Universal, and Filtek Ultimate) and one highly filled flowable (G-aenial Universal Injectable) universal composites (n = 40). Following storage in distilled water, each composite was randomly divided into four subgroups according to the discoloring solutions; black tea, coffee, red wine, and artificial saliva. Baseline, 7, 14, and 21-day color measurements (∆E₀₀) were performed while Ra was evaluated at baseline and 21 days. Data were analyzed using three-way ANOVA and post-hoc Tukey's tests (p < 0.05). The correlation between ∆E₀₀ and Ra was evaluated using Pearson's correlation test (p < 0.05). ∆E₀₀ and Ra were significantly influenced by the composite (p < 0.001), discoloring solution (p < 0.001), and the evaluation period (p < 0.001) while significant interactions were evaluated between the variables for both test methods. For all the composites and evaluation periods, red wine resulted significantly in the highest color change which was followed by black tea and coffee (p < 0.001). All the composites revealed significantly higher Ra after exposure to discoloring solutions (p < 0.001). There was a positive correlation between ∆E₀₀ and Ra with all the tested universal composites (p = 0.0001). All the tested universal composites revealed clinically unacceptable color change and increased surface roughness after exposure to discoloring solutions. Highly filled flowable universal composite showed the highest color stability in coffee, red wine, and black tea.