[Caries occurrence in schoolchildren of the canton of Glarus in 1974 to 1992: the effect of the use of fluoridated salt].

Between 1974 and 1976, fluoridated salt (250 ppm F) was introduced in the Swiss Canton of Glarus and has been used since by the bakeries and most households (domestic salt) in the Canton. Caries prevalence in schoolchildren of this Canton declined from 1974 to 1992 by 80 to 85%. As an example, 12-year-old children had 6.5 DMFT in 1974, but only 1.1 in 1992. In 1992, most DF sites were fissures and pits and most of them filled. Caries prevalence in primary teeth (dmft) decreased by 49 to 66% in the age groups 7, 8 and 9, and most of the reduction had occurred before 1983. In 1974, the average fluoride concentration in urine amounted to 0.36 ppm; between 1979 and 1992 it increased from 0.74 to 0.86 ppm. 46 to 60% of the bread samples contained between 3 to 9 ppm F; this bread had obviously been produced with fluoridated salt. Salt fluoridation contributed to caries decline until up to 1987, while subsequent caries reductions in permanent teeth must have been caused by other factors. In comparison to other Swiss data the caries prevalence of pupils in the Canton of Glarus was low in 1992.