Surface roughness and erosion of bulk-fill restorative materials after exposure to acidic beverages and brushing

Abstract

Objectives: To investigate the effects of acidic beverages regarding brushing on surface roughness and erosion of bulk-fill restorative materials. Methods: Sixty-seven specimens of each bulk-fill resin composite and giomer were prepared. Baseline data of surface roughness and erosion were recorded using a profilometer and surface characteristics were examined using scanning electron microscopy (SEM). Three groups of discs (n = 22) were alternately immersed in 300 mL of each beverage for 5 s and in 300 mL of artificial saliva for 5 s for 10 cycles. After immersion, specimens were divided into two subgroups, the brushing group with automatic toothbrush for 2 s with a force of 2 N and the non-brushing group. This process was repeated every 8 hours. Surface roughness and erosion was recorded again on day 7, 14, 21, and 28, and surface characteristics were examined on day 28. The specimens were evaluated and data were analyzed by repeated analysis of variance (ANOVA), Tukey’s honestly significant difference and t-test (α = 0.05). Results: Coca-cola caused significantly greater roughness and erosion than other groups (P <0.05). Giomer had significantly greater roughness and erosion than the bulk-fill resin composite (P < 0.05). Brushing groups caused a rougher surface than non-brushing groups (P < 0.05). Conclusions: The effects of coca-cola and orange juice on the surface roughness and erosion of bulk fill restorative materials depended on the physical and chemical composition of the restorative materials, pH of the beverages and brushing.