Color Stability of a New Rice Husk Composite in Comparison with Conventional Composites after Exposure to Commonly Consumed Beverages in Malaysia

Objective: 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.

Methods: 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
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color system. Color changes of samples (ΔE) 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 ΔE.

Results: The findings revealed a statistically significant difference of ΔE 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.

Conclusion: Rice husk composite showed acceptable color stability. It can be considered as an alternative to conventional composites due to its eco-friendly properties.