Staining and Aging-Dependent Changes in Translucency of CAD/CAM Materials

Objectives: To evaluate a CIEDE2000 translucency parameter (TP₀₀) of CAD/CAM hybrid and lithium disilicate ceramic materials submitted to staining and aging.
Methods: Square-shaped 1-mm thick specimens (n=8) were prepared from GC Cerasmart (CS), IPS Emax (IE), Lava Ultimate (LU), Shofu HC (SH), Vita Enamic (VE) and VITA Suprinity (VS). Upon chairside polishing in accordance with manufacturers’ instructions, color parameters were recorded using a benchtop spectrophotometer (D65, 2°). CIEDE2000 translucency parameter (TP00) was calculated as the difference in color of the same specimen measured against white and black backgrounds. After the baseline measurements (T₀), specimens were divided into 3 groups and exposed to staining in coffee (C) and wine (W), and accelerated artificial aging (A). Specimens were stored in staining solutions at 37°C for 60 (T₁) and 120 hours (T₂). Accelerated aging was performed using a xenon lamp weathering test chamber for a total exposure of 150 (T₁) and 300 kJ/m² (T₂). TP₀₀ data were analyzed by analysis of variance and Fisher’s PLSD multiple comparison test at α=0.05.
Results: Mean baseline TP₀₀ (s.d.) values and TP₀₀ retention (RT, %) for T₀-T₁ and T₀-T₂ interval comparisons, upon exposure to coffee (C), wine (W) and aging (A) are presented in the Table.
Fisher’s PLSD critical differences among materials, time intervals and staining/aging were 0.16, 0.11 and 0.11, respectively (p<0.001, power=1.0). SH showed the highest TP₀₀ followed by LU>CS>IE=VS>VE. For both time intervals (T₀-T₁ and T₀-T₂), the lowest TP₀₀ retention was observed with C. W and A presented similar values.
Conclusions: CIEDE20000 Translucency Parameter (TP₀₀) was material, time and staining/aging-dependent. In majority of cases, TP₀₀ decreased upon staining/aging.

Acknowledgment: Authors thank John M. Powers for statistical analysis.