Water fluoridation
Health and dental organizations worldwide have endorsed its safety and effectiveness. Its use began in 1945, following studies of children in a region where higher levels of fluoride occur naturally in the water. Further research showed that moderate fluoridation prevents tooth decay.
Fluoridation by country
Fluoridation is banned in China. Naturally high fluoride levels in water are a serious problem in China. As of 2003, there is no water fluoridation in China. Water fluoridation began in 1965 in the urban area of Guangzhou. It was interrupted during 1976–1978 due to the shortage of sodium silico-fluoride. It was resumed only in the Fangcun district of the city, due to objections, and was halted in 1983. The fluoridation reduced the number of cavities, but increased dental fluorosis; the fluoride levels could have been set too high, and low-quality equipment led to inconsistent, and often excessive, fluoride concentrations.