To evaluate the color stability of a new organic rice husk nanocomposite as compared to four conventional composites after exposure to commonly consumed beverages in Malaysia.
One hundred and twenty-five disk samples were prepared from a new rice husk-based composite and four other conventional methacrylate-based light-cured composites of shade A2. The samples were immersed in four commonly consumed beverages: coco-based drink, kopi, Chinese tea, and teh tarik for four weeks. The color measurements were carried out every week using the reflectance spectrophotometer according to the CIE L ∗ a ∗ b ∗ color system. Color changes of samples (Δ E) in each week were calculated. Statistical analysis was carried out by performing a mixed ANOVA and Tukey's post hoc test in order to analyse the differences in Δ E.
The findings revealed a statistically significant difference of Δ E reading ( p < 0.05) among all composites immersed in all four beverages after four weeks. Rice husk composites exhibited lesser color stability as compared to Ceram.X One Universal ( p < 0.001) and G-aenial Universal Flo ( p < 0.001) but showed higher color stability compared to Solare-X ( p < 0.001) and Neofil ( p < 0.001). Coffee and Chinese tea had the most significant impact on color changes ( p < 0.05) observed in all composites over four weeks of study.