Translucency Changes of Ceramic Veneers After Aging When Cemented on Substrates With Different Saturation: Effect of...

To evaluate the effect of ceramic translucency and resin cement shade on the translucency alteration after aging over different substrates.

Sixty specimens were divided into 12 groups (n = 5) composed of lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) in three translucencies (HT, MT, LT). The 0.5 mm thick specimens were cemented with Variolink Esthetic LC (Ivoclar Vivadent) Light+ (L+) and Neutral (N) over resin substrates A1 and A4. Samples were subjected to 20,000 aging thermocycles, alternating 55°C-5°C (30 s). Spectral reflectance was measured using a spectrophotometer (CM-3700d-Konica Minolta) at four intervals: before aging (t0) and after 10,000 (t10), 15,000 (t15), and 20,000 (t20) cycles. The Translucency Parameter (TP₀₀) and the ΔTP₀₀ were calculated. The thresholds for translucency perceptibility (TPT₀₀) and acceptability (TAT₀₀) were set at 0.62 and 2.62, respectively. Statistical analysis was performed using four-way repeated measures ANOVA and Tukey's post hoc test (α = 0.05).

Aging time, ceramic translucency, resin cement color and substrate saturation had a significant effect (p < 0.001) on TP₀₀. While TP₀₀ values declined across all groups, the lowest values for each measurement moment were consistently observed in the LTL+ groups [1.70 (t0) to 0.90 (t20)]. All ΔTP₀₀ values remained below the acceptability threshold (TAT = 2.62).

Aging resulted in a generalized decrease in translucency across all groups, particularly over lighter substrates and when using chromatic resin cement. However, no clinically unacceptable alterations were observed.

Clinicians should select materials based on the balance between initial masking and long-term stability. For dark substrates, LT ceramics ensure consistent optical stability during aging, regardless of the resin cement shade. While combining translucent ceramics (HT/MT) with chromatic resin cements is an effective strategy for initial masking, clinicians must be aware that ceramic translucency is the primary factor controlling the final optical outcome over time.