Discoloration of various CAD/CAM blocks after immersion in coffee.

Objectives: This study evaluated color differences (Δs) and translucency parameter changes (Δs) of various computer-aided design/computer-aided manufacturing (CAD/CAM) blocks after immersion in coffee.

Materials And Methods: Eight CAD/CAM blocks and four restorative composite resins were evaluated. The CIE values of 2.0 mm thick disk-shaped specimens were measured using the spectrophotometer on white and black backgrounds ( = 6). The Δs and Δs of one day, one week, and one month immersion in coffee or water were calculated. The values of each material were analyzed by two-way ANOVA and Tukey's multiple comparisons (α = 0.05). The Δs after prophylaxis paste polishing of 1 month coffee immersion specimens, water sorption and solubility were also evaluated.

Results: After one month in coffee, Δs of CAD/CAM composite resin blocks and restorative composites ranged from 1.6 to 3.7 and from 2.1 to 7.9, respectively, and Δs decreased. The ANOVA of Δs and Δs revealed significant differences in two main factors, immersion periods and media, and their interaction except for Δs of TEL (Telio CAD, Ivoclar Vivadent). The Δs significantly decreased after prophylaxis polishing except GRA (Gradia Block, GC). There was no significant correlation between Δs and water sorption or solubility in water.

Conclusions: The Δs of CAD/CAM blocks after immersion in coffee varied among products and were comparable to those of restorative composite resins. The discoloration of CAD/CAM composite resin blocks could be effectively removed with prophylaxis paste polishing, while that of some restorative composites could not be removed.