飲料水中フッ素濃度と永久歯う蝕り患状況

Abstract

This study deals with the prevalence of dental caries of permanent teeth and dental fluorosis among 5 th and 6th grade Japanese schoolchildren (aged 10-12), residing in 7 different communities in the Tohoku, Kanto, and Ko-Shin-Etsu districts, in relation to the differing concentrations ranging from 0.0 to 1.4ppm of fluoride in the communities' drinking water supplies.Information on dental health in school was obtained from school teachers, and data on dental habits at home were collected by a questionnaire filled out by parents.In 1987, children were examined for dental caries by three dentists, adopting the ‘Blind Recording Method’ where the dentists had no information about the communities, such as the fluoride concentration in the drinking water, and for dental fluorosis by means of Dean's index by two dentists.1, 060 children, who were continuous residents in their communities since birth, were selected for analysis. Comparing the prevalence of dental caries at a fluoride concentration of below 0.2ppm with that of above 1.0ppm, the maximum reduction rate was 69.6% in mean DMFS for 6th grade school-children.From Quantification theory (I), the highest factor was ‘fluoride concentration in the drinking water’, associated with the prevalence of dental caries of permanent teeth. The partial correlation coefficient of ‘fluoride concentration in the drinking water’ was -0.269. A secondary factor was ‘community’, and the other factors were very low. Thus, it became clear that there is an inverse relationship between the prevalence of dental caries and the fluoride concentration in the drinking water.In this study the optimal fluoride concentration in the drinking water that most effectively prevents dental caries in permanent teeth was 1.1 ppm.There was no public health problem regarding dental fluorosis, for CFI was under 0.30 at concentrations of 0.0 to 1.4ppm of fluoride in the drinking water.