Tea and Cola Stainability of Full Veneer Crowns Constructed from Repressed Conventional and Novel Lithium Disilicate...

To evaluate the change in color of ceramic crowns constructed from three different repressed ceramic ingots: lithium disilicate (LS), lithium silicate material reinforced with zirconia (ZLS), and repressed lithium silicate crowns with high-density micronization technology (LS-HDM). Each material underwent immersion in tea and cola solutions followed by brushing.

Three distinct heat-processed LS ceramic ingots representing three groups (N = 24)-e.max (EM), LiSi (Li), and Celtra (CA)-were used to manufacture 72 identical ceramic crowns. Three subgroups (n = 8) representing the experimental (tea and cola) and control (artificial saliva) groups were created from each group. Color changes were measured at the beginning, following tea and cola staining, and after brushing using the CIE L*a*b* system. The color changes (ΔE, ΔL, Δa, and Δb) were evaluated using one-way ANOVA, and post-hoc analysis was done to determine any significant differences between the groups.

The analysis revealed significant differences in color attributes (L, a, and b values) among crown materials, with variations observed following immersion in saliva and staining solutions. While all materials exhibited a decrease in L values post immersion, only CA showed significant changes in a and b values, indicating shifts in red and yellow components. Additionally, the overall color change (ΔE) remained below acceptability thresholds post-brushing, suggesting minimal perceptible differences. These findings underscore the materialspecific responses to staining agents.

Immersion of ceramic crowns made from LS, LS-HDM, and ZLS in tea and cola solutions resulted in noticeable color changes. However, regular tooth brushing effectively restored the satisfactory color appearance of stained ceramic crowns fabricated from repeatedly processed LSbased ingots.