Effect of Surface Finishing Procedures on the Color Stability of Resin-Matrix CAD/CAM Ceramics after Immersion in Common Beverages

Resin-matrix ceramics are increasingly used in digital dentistry due to their tooth-like elasticity and ease of handling. Color stability is critical for long-term clinical success. This study evaluated the effects of surface finishing and immersion in beverages on the color stability of four resin-matrix ceramics (Cerasmart, Lava Ultimate, Shofu Block HC, and Vita Enamic). A total of 256 specimens were prepared and divided into mechanical polishing and glazing. Glazing was performed using a light-polymerized resin-based surface coating agent (Optiglaze). Specimens were immersed for 14 days in coffee, red wine, cola, or water. Color differences were measured using the CIEDE2000 formula. Three-way repeated measures ANOVA was used to evaluate the color differences, and post hoc analyses were performed using Tukey and Bonferroni tests, with a significance level of p < 0.05. Results showed that surface finishing, material type, beverage type, and immersion time significantly affected color stability. Coffee and red wine caused clinically unacceptable color differences, while mechanically polished specimens demonstrated higher color stability than glazed ones. Lava Ultimate showed the lowest, and Cerasmart the highest, color stability. These findings highlight the role of surface finishing and material choice in maintaining the esthetics of resin-matrix ceramics in patients consuming pigmented beverages.