Longitudinal study of dental caries in Brazilian children aged from 12 to 30 months.

Objective: The purpose of the present study was to investigate caries in a sample of young children in Brazil.

Methods: A prospective longitudinal study of dental caries was carried out on a sample of 186 children aged from 12 to 30 months in Feira de Santana, Bahia, where the water supply is optimally fluoridated. The sample was composed of children accompanied by their mother or guardian and was part of a public health child care programme. After 11 months, all the mothers or guardians and children who took part in the initial examination were contacted, of whom 85.7% attended follow-up. Oral examinations for the detection of dental caries, visible plaque (VP) and white spots (WS) were performed at the beginning of the study and after one year. The statistical analysis consisted of frequency distributions, means and standard deviations, bivariate analysis, and calculation of relative risk, adopting confidence intervals of 95%.

Results: The prevalence of dental caries at the initial examination was 6.4%, rising approximately threefold by 12 months. When the presence of WS also took the form of dental caries, the prevalence of the disease almost doubled. A statistically significant difference was seen between the decayed, missing and filled primary teeth (dmft) found at the initial examination and that at the end of the study. In addition, there was an increase in the dmft index during the course of the study, both for the children who presented with WS and VP, and for those without these conditions.

Conclusions: A low prevalence of dental caries was observed among the children studied at the initial examination, but around 20% of these children presented with new disease during the period of the study. Amongst children with lesions at the start, the presence of caries almost doubled between examinations.