A multi-country comparison of caries-associated microflora in demographically diverse children

OBJECTIVE: The aim of this formative international collaborative research on childhood dental caries was to undertake an initial investigation comparing the dental plaque of young children from diverse ethnic and socioeconomic backgrounds with and without dental caries. BASIC RESEARCH DESIGN: The following four null hypotheses were investigated. There were no differences in numbers of individual taxa when comparing plaque samples from: 1) caries-free children from deprived and non-deprived backgrounds; 2) children from deprived and non-deprived backgrounds with at least 3 decayed teeth; 3) children from non-deprived backgrounds who are caries free with those from similar backgrounds with at least 3 decayed teeth; and, 4) children from deprived backgrounds who are caries free with those from similar backgrounds with at least 3 decayed teeth. PARTICIPANTS: 277 children aged 3-4 years from 5 countries. MAIN OUTCOME MEASURES: A sample of interproximal plaque from anterior teeth was collected using sterile dental floss, and cultured according to accepted international standards. RESULTS: Analysis of the data found that the first null hypothesis was accepted and that the fourth was rejected. Unexpectedly, the second null hypothesis was rejected as the children with caries from deprived and non-deprived backgrounds had a different caries-associated flora. In particular, children living in deprivation harbored more caries-associated bacteria [mutans streptococci and lactobacilli]. This greater microbial challenge was associated with a higher level of cavitated carious lesions and with more frequent consumption of confectionery. Conclusions Children from deprived backgrounds with caries may be further disadvantaged by having higher levels of caries-associated microflora