[Prevalence of dental caries, gingivitis, and fluorosis in 12-year-old students from Porto Alegre -- RS, Brazil, 1998/1999].

The aim of the study was to evaluate the prevalence of dental caries, gingival bleeding and fluorosis in twelve-year-old schoolchildren from Porto Alegre, Brazil. One thousand students from private and public schools were examined. The indexes used were BI, DMF and TFI. The data pertaining to BI were the first to be collected. After that, the children were submitted to plaque removal and their teeth were dried prior to the examination for caries and fluorosis. The average value for DMFT, including cavitated and non-cavitated lesions, was 2.22 +/- 0.08 (standard error). The average value for BI was 19.76% +/- 0.54% (standard error) and the prevalence of students with fluorosis was 52.9%. Regarding the severity of fluorosis, 45.9% of the children had TFI 1, 6.1% TFI 2 and 0.9% TFI 3. A polarization of the experience of caries and gingivitis was observed in the studied population. Only 14.4% of the students had DMFS higher than 7. A small percentage of children (12%) presented with BI > or = 40%. The experience of caries and gingivitis of 12-year-old schoolchildren in Porto Alegre is comparable to that of children from developed countries. That probably results from the intense utilization of fluoride, which is also causing an increased prevalence of fluorosis. The severity of fluorosis does not justify any public health measure. The results show that the employed public health measures are effective, although part of the population still needs additional care.