Color stability and degree of cure of direct composite restoratives after accelerated aging

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 E, 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 Delta L,* Delta a,* Delta b,* Delta E and %Delta RDB 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 alpha=0.05 significance level was used. Results: No statistically significant differences were found in Delta L*, Delta a*, Delta E and %Delta RDB among the materials tested. Tetric Ceram demonstrated a significant difference in Delta b*. All the materials showed visually perceptible (Delta E > 1) but clinically acceptable values (Delta E < 3.3). Within each material group, statistically significant differences in %RDB were noticed before and after aging (p < 0.05). Filtek Supreme presented the lowest %RDB before aging, with Tetric Ceram presenting the lowest %RDB after aging (p < 0.05). The %Delta RDB mean values were statistically significantly different among all the groups tested. No correlation was found between Delta E and %Delta RDB.