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.