Caries prevalence and salt fluoridation among 9-year-old schoolchildren in Strasbourg, France.

The 9-year-old group (236 children) of an epidemiological study carried out in 1991 in Strasbourg on children aged 6 to 15 years was selected with the aim of determining if the caries prevalence reduction observed could be related to the use of salt fluoridation (FS) introduced in France in 1987. From these 236 children, 143 answered a questionnaire which showed that 36 of them were fluoridated salt users and 107 were not. The dft index was significantly lower in the FS consumers which showed 35.5% dft reduction compared to the non-FS-consuming children. When using the Generalized Linear Model, this reduction was significant (P = 0.03). Although lower in the FS group, the DMFT and DMFS indices showed no statistical significant difference. It appeared that 72.2% of the users took simultaneously fluoride tablets but no dental fluorosis was observed. The use of fluoride tablets had a significant effect on the DMFS (P = 10(-2)). The children who consumed FS used more frequently fluoridated mouthrinses (P = 10(-3)) and had more frequent professional application of fluoridated gel and varnishes than non-consumers (P = 0.02). The DMFS index increased with the number of meals (P = 10(-6)), which was the most significant variable entered into the Generalized Linear Model. The children who brushed their teeth once a day had a DMFS value 2.6 times higher than those who brushed regularly three times a day (P = 10(-3)). The DMFS value was 4.4 times higher among the children who brushed their teeth irregularly when compared with those who brushed three times a day (P = 10(-2)).