Water fluoridation results in Basel since 1962: health and political implications

The population of the canton Basel-City has been provided with fluoridated water since May 1962. This paper presents a summary of basic findings from evaluations of this public health intervention. Standard methods were used for assessing dental caries, enamel fluorosis, urinary fluoride, and other data. Caries prevalence of schoolchildren declined until 1977 because of water fluoridation, after which it continued to decline until the late 1980s due to reasons other than water fluoridation. Caries prevalence in Basel was at least as low as in those other parts of Switzerland where either school-based dental health education programs or comprehensive salt fluoridation programs had been implemented for many years. Enamel fluorosis was seen in 38 percent of the children, similar to regions with comprehensive salt fluoridation, but higher than in low-fluoride regions. Overlap of salt and water fluoridation in families consuming both fluoridated water and fluoridated salt has occurred, but has not resulted in problems. Fluoride concentrations (close to, but mostly below 1.0 ppm) and excretions (0.45-0.80 mg F per day in children, around 1 mg in adults) corresponded to expected levels. Statistics from both the School Dental Service and the Public Dental Clinic indicate a dramatic reduction in the amount of conservation dentistry being done and, in adults, prosthetic services. Political steps to remove water fluoridation were taken in 1976, 1982, 1989, and 1993, but have not been successful. Water fluoridation has resulted in the expected benefit and continues to exist beside salt fluoridation used in the other cantons of Switzerland.