RESUMO

OBJECTIVES: Frequent consumption of sugars-containing carbonated beverages has been associated with caries, but the consequences on the dental biofilm remain unclear. The aim was to evaluate the effect of commercial carbonated beverages and their sugar-free version on enamel and dentine demineralization and on the cariogenic properties of Streptococcus mutans biofilms. MATERIALS AND METHODS: Biofilms of S. mutans UA159 were grown on enamel and dentin slabs and exposed 3 times/day for 5 min, to a commercial cola or orange-flavored carbonated beverage or to their sugar-free version. Biofilms/slabs were recovered to assess biomass, viable microorganisms, protein content and polysaccharides. Demineralization was estimated by the variation of Knoop surface microhardness. RESULTS: Exposures to the biofilm with sugars-containing carbonated beverages resulted in similar biomass, viable microorganisms, proteins, and polysaccharides than sucrose (P < 0.05). The sugar-free cola and orange-flavored drink showed lower effect on the biofilm, as compared with sucrose or their sugared version (P < 0.05). All of the products tested, included the sugar-free, showed higher demineralization than the negative control (P < 0.05). CONCLUSIONS: Sugars-containing carbonated beverages enhance cariogenic activity of S. mutans biofilms, comparable with sucrose. Sugar-free carbonated beverages also have a high demineralizing potential, without affecting biofilm properties.