A 2009 study found that about 21% of water sources naturally containing fluoride to the recommended range of 0.3–0.6 ppm, about 62% have fluoride below this range, and the remainder are above this range.
While fluoridation can result in mild dental fluorosis, this effect is barely detectable and causes no concerns with the appearance or health of teeth.Fluoridated water operates on tooth surfaces: in the mouth it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.Most European countries have experienced substantial declines in tooth decay without its use.Water is fluoridated in Egypt, with no recommended minimum value but with a maximum value of 0.8 mg/L.Before 2003, 400,000 Libyans were receiving artificially-fluoridated water.Recent studies suggest that water fluoridation, particularly in industrialized countries, may be unnecessary because topical fluorides (such as in toothpaste) are widely used and caries rates have become low.
The views on the most effective method for community prevention of tooth decay are mixed.
Supporters say the small amount put into water is safe, but opponents of the process point out that once the chemical is put into water, its dose cannot be easily controlled or monitored since people drink widely varying amounts of water and have different body weights and ability to process the mineral.
study in the medical journal The Lancet earlier this year labeled fluoride a developmental neurotoxin, due to a link between high levels of exposure and reduced IQ in children, mostly in China.
The decision has “been lauded by various rights groups, but criticized by many in the medical and dental communities as a serious mistake,” as the Times of Israel put it.water fluoridation is not practiced in most of Europe or most countries worldwide, it has become widespread in the United States, Canada, Ireland, New Zealand and Australia, and a few others.
It remains contentious where it is practiced, especially outside of the United States; however, fluoridation was recently voted against in Portland, Ore.
This information is updated every three months - the next update will be in December 2017 when drinking water quality information for January to September 2017 will be available.