[The dental health of permanently resident schoolchildren in 16 Zurich rural communities in 1992].

Between 1964 and 1992, caries prevalence (DMFT) of permanently resident school children in 16 communities in the Canton of Zurich decreased by 85 to 87%. In the ten- to fourteen-year-olds, the reduction amounted to 25-29% in the period of 1988 to 1992. In 1992, the fourteen-year-olds had only 1.90 DMFT and 2.49 DFS, the average DS being 0.28. The 21% children with the highest caries experience showed only 9 DFS on average. Such a low caries activity does not favour positive cost-benefit results for individual intensive prevention. From 1964 to 1984 caries prevalence in primary teeth of 7-year-old children decreased to the level of 1.81 dmft; the further reduction to 1.55 dmft in 1992 was not significant. Few primary molars were lost prematurely. According to a saliva-test, 59% of the children aged 10 to 12 with high concentrations of mutans streptococci were free of caries; by comparison, 80% of the children with the lowest mutans-test value, were free of caries. In spite of the easy availability and the multiple usages of fluorides (dentifrices with either 250 or 1000-1500 ppm F, domestic salt, gels with 12,500 ppm F and rinsing solutions with 230 ppm F since 1986-88), only 16% of the children showed signs of dental fluorosis.