Tiel-Culemborg Netherlands

• Cross-sectional study of dentinal caries based on standardized bite-wing x-rays of permanent teeth

• Tiel, Netherlands, began fluoridating water at 1 ppm in 1953 and stopped Dec 1973 under court order. Culemborg served as non-fluoridated control

• Data collected in 1961, 1973, and 1979-86

• In all categories of surfaces (proximal, smooth, pit & fissure) the use of fluoridated water only post-eruptively shows less effect than the use only pre-eruptively.

• “In order to obtain maximal reduction in all surfaces the use of fluoridated water must be started at onset of calcification of a tooth.”