Association between biofilm-forming isolates of mutans streptococci and caries experience in adults

ObjectivesAlthough it is still controversial, mutans streptococci (MS) have been typically considered the primary etiological agents of dental caries. Besides the acidogenic and aciduric properties, extracellular polysaccharide synthesis leading to biofilm formation from sugar constitutes one of the key virulence factors of MS. The aim of this study was to investigate whether biofilm formation by MS was associated to an increased experience of caries in young adults.MethodsA cross sectional study with a total of 96 randomly selected patients aged 15–27 years old was carried out. DMFT was determined by clinical examination and bite-wing radiographs. A sample of stimulated saliva was obtained and seeded on agar plates to culture MS. Colonies with and without biofilm formation were identified and quantified.ResultsWhen the total MS count was considered, levels of MS were not associated with higher caries experience. 50% of the patients showed at least one biofilm-forming colony. Patients with biofilm-forming colonies showed significantly higher DMFT (p < 0.001) than individuals whose plates did not reveal the structure surrounding the colony, but only at the low and moderate MS count.ConclusionBiofilm formation in MS appears to be associated with higher caries experience in individuals with low counts of the cariogenic microorganism.