Longitudinal study of prevalence of enamel lesions in a fluoridated and non-fluoridated area.

The aim of this study was to examine longitudinally the effect of water fluoridation on the prevalence of enamel lesions in children 7-18 yr of age. 93 children in Tiel (1 ppm F-) and 103 children in Culemborg (0.1 ppm F-) were examined every other year at 7, 9, 11, 13 and 15 yr of age. A supplementary examination was carried out when these children reached the age of 18. Children in Tiel had access to water fluoridation from birth. The total number of lesions, including enamel lesions, on the buccal as well as on the occlusal surfaces was approximately the same in both areas in children 15 and 18 yr of age. Approximal lesions were scored on standardized bitewing radiographs. A large proportion of enamel lesions could not be detected on radiographs. In a fluoridated area a high percentage of all lesions remain in the stage of enamel caries lesions. On buccal surfaces 93% and on approximal surfaces 86% of all lesions had not progressed into the dentin. In Culemborg these percentages were 65 for approximal as well as for buccal surfaces. At the initiation of lesions, at younger ages, only a small retardation of the process was observed, but caries progression beyond the stage of enamel caries was markedly reduced in the fluoridated area. No pre-eruptive effect could be observed if the total number of lesions, including enamel lesions, from Tiel and Culemborg were compared.