Color Stability of CAD/CAM Nano-Hybrid Ceramics

Objectives: We compared the color stability of CAD/CAM nano-hybrid ceramics pre- and post- exposure to coffee and red wine.
Methods: Blocks of CAD/CAM nano-hybrid ceramic (Cerasmart, GC America, Alsip, IL) were cut into 2x16x10mm samples. Samples were blasted with oil-free compressed air to ensure complete removal of material dust. Finishing and polishing were performed following manufacturer’s protocol. Color coordinates L* (luminescence), a* (red/green), and b* (blue/yellow) were measured using a colorimeter (Spectro2guide, BYK Gardner, Columbia, MD). Specimens were randomly allocated into 3 groups (n=15/group): Stained with coffee; Stained with red wine; Stained with water (control). Staining-challenge was performed by incubation in coffee, wine, or water for 12 days at 37°C. Changes in specimen color (ΔE) were analyzed by repeated measures ANOVA and Tukey post-hoc tests (α=0.05). ΔE > 2 was considered significant.
Results: Stained samples (coffee or wine) showed significant ΔE differences compared to non-stained samples (water) (p<0.05): DE=3.069 (coffee-stained samples); DE=2.102 (wine-stained samples); DE=0.968 (water-stained samples). Differences in ΔE for stained groups (coffee vs. wine) were lower than 2.0, considered not to be detectable by the average observer.
Conclusions: Frequent and prolonged exposure to coffee or wine might affect the optical characteristics of the new generation of nano-hybrid ceramics manufactured for CAD/CAM purposes.