The effect of different beverages on surface hardness of nanohybrid resin composite and giomer

AIMS: To investigate the effects of five beverages (apple cider, orange juice, Coca-Cola, coffee, and beer) on microhardness and surface characteristic changes of nanohybrid resin composite and giomer. MATERIALS AND METHODS: Ninety-three specimens of each resin composite and giomer were prepared. Before immersion, baseline data of Vicker's microhardness was recorded and surface characteristics were examined using scanning electron microscopy (SEM). Five groups of discs (n = 18) were alternately immersed in 25 mL of each beverage for 5 s and in 25 mL of artificial saliva for 5 s for 10 cycles. Specimens were then stored in artificial saliva for 24 h. This process was repeated for 28 days. After immersion, specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA), Tukey's honestly significant difference (HSD), and a t-test (α = 0.05). RESULTS: Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05). SEM photomicrographs presented surface degradation of all groups. CONCLUSIONS: The effect of these beverages on the surface of both restorative materials also depended upon the exposure time and chemical composition of the restorative materials and beverages.