Protective Effects of GIC and S-PRG Filler Restoratives on Demineralization of Bovine Enamel in Lactic Acid Solution

We investigated the protective effects of glass ionomer cement (GIC) and surface pre-reacted glass ionomer (S-PRG) fillers used as dental restorative materials on the demineralization of bovine enamel during the incubation in a lactic acid solution with pH = 4.0 conducted for 6 d at a temperature of 37 °C. Scanning electron microscopy images of the specimen surfaces from the group containing only enamel blocks revealed the presence of apparent enamel prism peripheries after 6 d of treatment. The mineral was etched from the enamel surface, and a large number of Ca ions were detected in solution. In contrast, the enamel blocks incubated together with discs of GIC or S-PRG fillers did not exhibit demineralized surfaces, owing to the neutralization of the acid solution by the fillers within the first 3 h of the incubation process. The observed pH neutralization effect was attributed to the release of different ions from the fillers and could be utilized for suppressing the progression of caries.