Dental fluorosis in salt fluoridation schemes

The prevalences of fluoride-associated opacities (FOP) and nonfluoride-associated opacities (non-FOP) were assessed in two cantons of Switzerland with different salt fluoridation schemes. In the Canton of Zurich 305 schoolchildren from eight communities (age 9-10) were examined in 1995 and 900 children from one community (age 8-16) in 2002. In the Canton of Glarus 144 schoolchildren from 14 communities (age 9-10) were examined in 1996. In the Canton of Zurich 84% of the children used fluoridated domestic salt (250 ppm F) in the first five years of their life (questionnaire for parents 1995). In the Canton of Glarus, the corresponding value was 87%. In addition, about half of the bread samples in the Canton of Glarus showed an increased fluoride content (> 3 ppm F). Standardized photographs were taken of incisors dried with compressed air (15 seconds) and assessed using the Thylstrup Fejerskov index. The prevalence of FOP was 21% in eight communities of the Canton of Zurich (1995) and 22% in 14 communities of the Canton of Glarus (1996). No differences were found between these two locations, although fluoride intake was higher in the Canton of Glarus due to fluoridated salt used by bakeries. A recent examination in one community of the Canton of Zurich (2002) showed a lower prevalence of 11%. The prevalences of non-FOP in all locations were between 17% and 23%. The prevalences of FOP were at a low level in Switzerland compared to international studies using the same index. The most plausible explanation for this difference is the widespread use of low fluoride toothpastes (250 ppm F) by children under six. These toothpastes were introduced in 1986 and the consumption increased continuously until 1992. The low FOP prevalence cannot be considered a public health problem and is not perceived as such by the population. It is concluded that the Swiss fluoridation policy of the past two decades was approprate, with caries prevalence in permanent teeth of Swiss schoolchildren being among the lowest globally.