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 controversy
The World Health Organization, looking at global public health, identifies fluoride as one of a few chemicals for which the contribution from drinking-water to overall intake is an important factor in preventing disease. This is because there is clear evidence that optimal concentrations of fluoride provide protection against cavities, both in children and in adults.