Color Stability and Degree of Cure of Direct Composite Restoratives After Accelerated Aging

Abstract

Accelerated hydrothermal- and photo-aging of direct light-cured composite restorative materials induced visually perceptible but clinically acceptable total color changes, along with a reduction in the amount of remaining C=C bonds. Purpose: This study evaluated the color changes and amount of remaining C=C bonds (%RDB) in three dental composites after hydrothermal- and photoaging. Methods and Materials: The materials tested were Estelite Σ, Filtek Supreme and Tetric Ceram. Specimens were fabricated from each material and subjected to L* a* b* colorimetry and FTIR spectroscopy before and after aging. Statistical evaluation of the ΔL,* Δa,* Δb,* ΔE and %ΔRDB data was performed by one-way ANOVA and Tukey's test. The %RDB data before and after aging were statistically analyzed using two-way ANOVA and Student-Newman-Keuls test. In all cases an α=0.05 significance level was used. Results: No statistically significant differences were found in ΔL*, Δa*, ΔE and %ΔRDB among the materials tested. Tetric Ceram demonstrated a significant difference in Δb*. All the materials showed visually perceptible (ΔE>1) but clinically acceptable values (ΔEpp<0.05). The %ΔRDB mean values were statistically significantly different among all the groups tested. No correlation was found between ΔE and %ΔRDB.