In 1988, 100 12- to 13-year-old children from two neighborhoods in Montevideo with different standards of living were examined. Twenty-three children with large numbers of mutans streptococci, lactobacilli, or decayed surfaces or a combination of these factors were considered to be at high risk of developing caries. Twelve of these 23 children were selected for special preventive measures. A second examination was made 18 months later, at which 81 of the originally 100 children were studied. The clinical and microbiologic variables were tested for their ability to predict caries by calculating their sensitivity, specificity, the positive and negative predictive values. The incidence of new DMFS was significantly higher in the children from the low than in those from the high socioeconomic area. It was also significantly higher in the children considered being at high risk than in those at low risk at the start of the study. Preventive measures reduced the caries risk. The highest sensitivity was obtained with the clinical test, whereas the highest specificity was obtained with the combined clinical and microbiologic tests. The findings indicate that methods for identifying children at risk which started to be used in Scandinavia 20 years ago could be applied in the Uruguayan population of today. It is valuable to know this, as the resources for both treatment and prevention are very limited.

Dental caries, microbial and salivary conditions, dietary habits, and socioeconomic conditions were studied in 100 12- to 13-year-old children from 2 different socioeconomic areas in Montevideo: Pocitos and Piedras Blancas. The residents of Pocitos had a higher educational level, better housing conditions, and occupations involving higher earnings than those of Piedras Blancas. The caries prevalence in the two areas was about the same, but the children in Piedras Blancas had more decayed surfaces and fewer filled surfaces than the children in Pocitos. The mean values for caries in Piedras Blancas and Pocitos were, DMFT, 4.2 and 4.2; DMFS, 8.1 and 7.8; DS, 4.7 and 2.5; and FS, 1.7 and 4.7, respectively. The differences in DS and FS were statistically significant. The frequency of sugar intake and the salivary secretion rate were similar, but the buffer capacity was significantly higher in Pocitos than in Piedras Blancas. The plaque index was the same, but the distribution of cariogenic microorganisms differed significantly. Fifty-eight per cent of the children in Piedras Blancas had more than 10(6) CFU of mutans streptococci per milliliter saliva, compared with 17% of the children in Pocitos. Similar differences were found with regard to the lactobacilli. The percentage of children with high numbers of mutans streptococci was higher in Piedras Blancas and lower in Pocitos than in previous epidemiologic studies in Scandinavia. It was, however, higher than that recently noted in Finland.