IADR Abstract Archives
Color Stability and Microhardness of CAD/CAM Lithium Disilicate Ceramics
Objectives: We compared the color stability and microhardness of CAD/CAM lithium disilicate ceramics pre- and post-exposure to coffee, red wine, and an at-home bleaching product.
Methods: CAD/CAM lithium disilicate blocks (Emax, Ivoclar Vivadent, Amherst, NY), shade A2, were cut into 2x14x12mm specimens. Samples were blasted with oil-free compressed air to ensure complete removal of lithium disilicate dust. Polishing tips and discs (OptraGloss, Ivoclar Vivadent, Amherst, NY) were used to polish specimen surfaces. Samples were crystallized 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). Baseline surface Vickers microhardness was obtained under a load of 4.9N/15s (Phase II Micro Vickers Hardness Tester, Upper Saddle River, NJ). Ceramic specimens were randomly allocated into 3 groups (n=15): Stained with coffee; Stained with red wine; water (control). Staining challenge was performed by incubation in coffee, wine, or water for 12 days at 37°C. Changes in color (ΔE) and surface microhardness (VSH) were analyzed by repeated measures ANOVA and Tukey post-hoc tests (α=0.05). Changes in color were considered significant at ΔE>2.
Results: Stained samples (coffee or wine) showed significant change in ΔE compared to control (water) (p<0.05). Samples stained with red wine had a numerically higher ΔE compared to those stained with coffee, although differences between these groups were not significant. Microhardness showed no differences between samples stained with coffee and wine versus control.
Conclusions: Coffee and red wine affected the appearance/color of lithium disilicate. Microhardness of lithium disilicate was not affected by the exposure to coffee or red wine.
Methods: CAD/CAM lithium disilicate blocks (Emax, Ivoclar Vivadent, Amherst, NY), shade A2, were cut into 2x14x12mm specimens. Samples were blasted with oil-free compressed air to ensure complete removal of lithium disilicate dust. Polishing tips and discs (OptraGloss, Ivoclar Vivadent, Amherst, NY) were used to polish specimen surfaces. Samples were crystallized 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). Baseline surface Vickers microhardness was obtained under a load of 4.9N/15s (Phase II Micro Vickers Hardness Tester, Upper Saddle River, NJ). Ceramic specimens were randomly allocated into 3 groups (n=15): Stained with coffee; Stained with red wine; water (control). Staining challenge was performed by incubation in coffee, wine, or water for 12 days at 37°C. Changes in color (ΔE) and surface microhardness (VSH) were analyzed by repeated measures ANOVA and Tukey post-hoc tests (α=0.05). Changes in color were considered significant at ΔE>2.
Results: Stained samples (coffee or wine) showed significant change in ΔE compared to control (water) (p<0.05). Samples stained with red wine had a numerically higher ΔE compared to those stained with coffee, although differences between these groups were not significant. Microhardness showed no differences between samples stained with coffee and wine versus control.
Conclusions: Coffee and red wine affected the appearance/color of lithium disilicate. Microhardness of lithium disilicate was not affected by the exposure to coffee or red wine.