To compare color and translucency changes after water ageing for one-week and one-month in light and dark shades of contemporary polychromatic resin composites.
Enamel (e) and dentine (d), light and dark (A1 and A4 or equivalents) shades were selected from the composites Enamel-Plus HRi/Micerium, Miris-2/Coltene, IPS Empress-Direct/Ivoclar and Filtek-Supreme/3M ESPE and light and dark shades from the TPH-Spectum/Densply monochromatic composite. Five disks (d = 10mm, h = 1mm) per material, enamel/dentine and light/dark shade were prepared. A colorimetric evaluation, over white and black background, according to the CIELab system was performed just after preparation and after one-week and one-month dark water-storage at 37°C. Color (¿Eab) and translucency (¿TP) differences were calculated. Results were analysed by ANOVA and Scheffe's test, paired t-test and linear regression analysis (a = 0.05).
One-week water ageing provided a wide range of ¿Eab values (0.79 Filtek(e)/D2 to 5.19 Filtek(d)/A1) and ¿TP values (-2.74 Hri/UD1 to 1.03 TPH/A1). After one-month water ageing ¿Eab ranged from 1.09 Filtek(e)/D2 to 7.94 Filtek(d)/A1 and ¿TP values from -2.71Hri/UD1 to 1.07 Filtek(d)/A4. Significant changes in ¿Eab between one-week and one-month water ageing were noted for Filtek and Miris dentine and Miris light enamel shades. As for ¿TP, significant difference was recorded only for IPS(e)/A4. ¿Eab was significantly correlated with ¿L, ¿a, ¿b and ¿TP after one-week and with ¿L and ¿a after one-month ageing.
Water ageing caused remarkable color changes, which were material and shade depended. Thirteen out of eighteen of the tested composites exhibited clinically perceptible (¿Eab>2.6) color changes even after short water ageing period.