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.
Water fluoridation in the United States
In 1939, Dr. Gerald J. Cox conducted laboratory tests using rats that were fed aluminum and fluoride. Dr. Cox suggested adding fluoride to drinking water (or other media such as milk or bottled water) in order to improve oral health.