The Impact of Coffee, Matcha, Protein Drinks, and Water Storage on the Microhardness and Color Stability of a Nano-Ceramic Hybrid Composite CAD/CAM Blank.

This study aimed to evaluate the effect of popular beverages, coffee, matcha, and protein isolate, on the microhardness and color stability of feldspar glass ceramic (VB) and nano-ceramic hybrid composite (GD) CAD/CAM materials. Three hundred specimens were prepared and divided into control and immersion groups (water, coffee, matcha, protein). Vicker's microhardness (HN) was recorded for the control group and post-immersion groups, while color changes were measured before and after immersion. Microhardness values (HN) and color change (ΔE00) were statistically analyzed using the Kruskal-Wallis test followed by Dunn's post hoc test (p < 0.05). Results: The HN values of all VB and GD immersion subgroups were significantly lower than those of the control groups (p < 0.001). The VB water immersion group had a significantly lower HN than the protein and matcha immersion groups. The GD immersion groups showed no significant difference in HN between them (p > 0.05). VB had a significantly lower ΔE00 (>3.5) and higher HN (790.8 ± 123.62 kgf/mm2) than GD (175.22 ± 28.95 kgf/mm2) (p < 0.001). Coffee caused the greatest ΔE00 in both VB and GD, whereas protein caused the lowest ΔE00 in GD. Conclusion: The study revealed that the feldspar glass ceramic CAD/CAM material had higher microhardness and color stability than the nano-ceramic hybrid composite. Immersion reduces the microhardness and color stability of CAD/CAM ceramics. Matcha and protein have less impact on glass ceramic microhardness, with protein causing less discoloration in nano-ceramic hybrid composites than other immersion media.