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This study evaluated the optical properties of new composite resins used for class V restorations under accelerated aging. Composite resins (DY, PD, RV, AF, TP, and DF) were tested. Five sample disks (10 mm in diameter, 1 r;m in thickness) were prepared in poly-tetrafluoroethylene die between transparency strips and stored for 24 h in deionized water at 37 C before testing. Samples were aged in a Weather-Ometer by exposure to a filtered xenon arc at an irradiance of 0.55 W/m2/nm @ 340 nm for a total ultraviolet irradiation of 450 KJm´. Tristimulus values for CIE standard Illuminan+t C were measured by a reflection spectrophotometer at wavelengths of every 10 nrn between 360 nm and 750 nm against white and black backgrounds at baseline and after accelerated aging. The absorption coefficient (K), scattering coefficient (S), infinite optical thickness (XI), and contrast ratio (CR) at baseline and after aging were obtained using Kubelkas equations. Means and standard deviations were determined. Th<´ effects of aging on the parameters were analyzed by ANOVA(P < 0.05). Differences of optical properties among products were not big. S values except RV and DF and K values except´ PR and AF were significantly increased under accelerated aging. XI and CR values except PR were significantly decreased under accelerated aging.
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