Color stability and surface roughness of novel single-shade universal composite resins exposed to staining solutions: an in vitro study.

This study investigated the color stability and surface roughness of three novel single-shade universal composites after exposure to common staining solutions. A total of 120 specimens (n = 40 per composite) were fabricated from Transcend Universal Composite (TRA), Ecosite One (ECO), and Clearfil Majesty ES-2 Universal (CLA). Specimens were stored at 37 °C in four different staining solutions (artificial saliva, coffee, red wine, matcha tea). Color changes (ΔE₀₀) were assessed at five time points using the eLAB system, and surface roughness (Sa, Sz) was analyzed via 3D laser scanning microscopy. Statistical analysis was performed using a linear mixed model and post-hoc test (Tukey) (p < 0.05). Composite type, staining solution, and exposure duration significantly affected discoloration (p < 0.001). Red wine induced the most pronounced color change (ECO: ΔE₀₀ = 38.9 ± 1.56), while coffee and matcha tea caused similar discoloration (p = 0.164). TRA showed the greatest surface roughness increase; no correlation with color change was observed. The color stability of single-shade composites is influenced by resin matrix composition and staining agent exposure. Tri-modal or nanohybrid composites showed greater color stability than the micro hybrid composite. Surface roughness did not impact discoloration susceptibility.