Color Stability of Different CAD/CAM Blocks Against Coloration With Coffee

Objectives: This study evaluated color differences (ΔEs) of various computer-aided design/computer-aided manufacturing (CAD/CAM) blocks after immersion in coffee.
Methods: Specimens from different CAD/CAM materials [(Lava ultimate (resin nanoceramic), Ceresmart (Hybrid ceramic), Grandi (Nanohybrid composite)] were prepared in 10x10x2 mm dimensions and polished according to the manufacturer's instructions (n=10 per series). The samples were kept in coffee in an incubator at 37 °C for 5 days for coloring. The CIE L*a*b* values of the specimens were measured using a spectrophotometer (Vita Easy Shade, Germany) on a white background before and after immersion coffee. The color change value, Delta E (ΔE), was calculated. Data were analyzed by one-way ANOVA and post hoc Tukey's test. P value of less than 0.05 was considered statistically significant for all tests. In the measurement of coloration change, it was obtained by evaluating ΔE value over 3.3.
Results: The average ΔE values of the coffee-colored CAD/CAM samples were 5.06 in the Lava group, 3.18 in the Cerasmart group and 4.13 in the Grandi group. There was a statistical difference between the ΔE values of the coffee colored Lava group and the Cerasmart group (p <0.05). The coffee-colored Grandi group showed similar ΔE values with the other groups (p >0.05). The mean delta E values of Lava and Grandi groups were higher than the 3.3 value, which is perceived by the eye.
Conclusions: After 5 days of coloring with coffee, Lava and Grandi groups showed unacceptable color changes. Cerasmart group showed acceptable color change.