Methods: One hundred disk-shaped composites, with 10 mm of diameter and 2 mm thickness, were made of five light-cured resin composites (EH, Enamel Plus™ Hri (Micerium S.p.A., Avegno, Italy,); LS, Llis (FGM, Joinville, Brasil); HX, Herculite XRV (Kerr, Washington D.C., USA); HXU, Herculite XRV Ultra (Kerr, Washington D.C., USA) e FS, Filtek™ Supreme XTE (3M ESPE, St. Paul, USA)). Twenty specimens were made for each material. Ten specimens were immersed in artificial saliva, and the other ten were immersed in artificial saliva with esterase enzyme (porcine liver esterase, 400 mU/mL), over a period of 21 days. Color was measured according to the CIEL*a*b* scale, after 7, 14 and 21 days. Inferential statistics analysis was performed at a 5% significance level in order to compare the results. Data were analysed with one-way ANOVA and Student’s t test. Repeated measures ANOVA was used for time evaluation of the samples. Wilcoxon test was used for paired samples comparison of the L*, a* e b* parameters between the initial and the final experimental period.
Results: Color stability of dental materials changed after immersion periods. The ΔE value was significantly higher with LS, after immersion in artificial saliva with esterase enzyme. The ΔE value was higher with EH after storage in artificial saliva. Poor color stability was observed for LS. The lowest variation was observed for EH.
Conclusion: Changes in color stability of resin composites were observed after immersion in a salivary enzyme. The variability of color can be due to filler composition and content, resin matrix composition and immersion solutions.