Acid formation in sucrose-exposed dental plaque in relation to caries incidence in schoolchildren.

The aim was to investigate the composition and concentration of organic acids produced by plaque bacteria in vivo and its possible relation to caries development in schoolchildren. Sucrose-exposed pooled plaque from 25 healthy teenagers was collected and the levels of Streptococcus mutans and lactobacilli were estimated. The acid anions were analysed with isotachophoresis. The prevalence and incidence of dental caries during a 2-year period was recorded. Depending on the amount of plaque collected, the subjects were divided into a low (n = 12) and a high (n = 13) plaque weight group. The dominating anions in sucrose exposed plaque were lactate, acetate and propionate. For the entire study group, no association was found between the total acid concentration and caries development but for the participants with low plaque weight a positive relationship (P < 0.01) was disclosed. No correlation was found between the concentrations of acids and the number of lactobacilli or Streptococcus mutans. The present results did not suggest that the acidogenicity of sugar-exposed pooled plaque samples was a suitable indicator of caries activity in teenagers.