Accelerated Aging Effects on Color and Translucency of Resin Composites

Objectives: To evaluate the influence of accelerated aging on the color and translucency parameter (TP) of bulk-fill and universal resin composites.
Methods: Forty disc-shaped specimens (10mm in diameter, 2mm thick, n=5) were fabricated from 4 pairs of bulk-fill – universal resin composites listed in the table. Color and TP were measured using a contact-type spectrophotometer before (T0) and after exposure to controlled irradiance of 150 kJ/m² and 300 kJ/m² (T1 and T2, respectively) in an accelerated aging chamber. Means and standard deviations were calculated. The data were analyzed by ANOVA. Fisher’s PLSD multiple comparison intervals were calculated at the 0.05 level of significance. A color difference of ΔE*=2.7 (50:50% acceptability threshold, AT), was used for interpretation of color differences.
Results: Means (s.d.) of color differences (ΔE*) between T0-T1 and T0-T2 are listed in table.
The ANOVA revealed that differences between ΔE* values for T0-T1 and T0-T2 were statistically significant (p<0.0001), while the Fisher’s PLSD intervals for comparinson among materials and between aging periods were 0.3 and 0.2, respectively. Compared to baseline, 5 and 4 composites exhibited color differences at/below the 50:50% AT at 150 kJ/m² and 300 kJ/m², respectively. TP at baseline ranged from 5.6 to 13.2. There were significant differences in TP among the composites but no significant differences between aging intervals (T0-T1 and T0-T2).
Conclusions: Within the limitations of this study, it was concluded that artificial aging influenced color of evaluated composites, some of them beyond the 50:50% acceptability threshold, while it did not affect translucency parameter.