Effect of artificial accelerated aging on color stability of CAD/CAM laminate veneers: a comparative in‑vitro study of lithium disilicate, leucite‑reinforced, and resin nano‑ceramic materials

Background Color stability of ultra-thin CAD/CAM veneers is critical for long-term esthetics. This in‑vitro study compared color change (ΔE, CIELAB) before and after artificial accelerated aging (AAA) among a lithium disilicate glass-ceramic (IPS e.max CAD), a leucite-reinforced glass-ceramic (IPS Empress CAD), and a resin nano-ceramic (Lava Ultimate). Methods Thirty standardized veneers (n = 10/material) were milled and luted to epoxy-dentin analog dies with a light‑cure veneer cement. L*, a*, b* were recorded with a portable reflective spectrophotometer pre‑ and post‑AAA. AAA used a Jeio Tech TEMI‑300 environmental chamber with UV‑B (280–320 nm), 4 h UV at 50°C alternating with 4 h condensation for 300 h. ΔE*ab was computed as [(ΔL*)²+(Δa*)²+(Δb*)²]¹ᐟ². Normality was checked; paired t, Wilcoxon, Kruskal–Wallis and Mann–Whitney tests were used (α = 0.05). [26] Results Mean ΔE (± SD): IPS e.max CAD 4.33 ± 1.79; IPS Empress CAD 3.67 ± 0.65; Lava Ultimate 3.49 ± 1.17 (between‑materials p = 0.784). Lava Ultimate showed a significant decrease in a* post‑aging; other L*, a*, b* changes were not significant within material. Conclusions All materials exhibited perceptible discoloration after AAA. Under these conditions, lithium disilicate exceeded common acceptability thresholds, while the resin nano‑ceramic showed a* reduction but overall ΔE similar to glass‑ceramics. Clinical selection should consider translucency and potential ΔE shifts after UV/condensation exposure. [24, 39]