Consuming excess fluoride, most commonly by drinking water that has a high fluoride level or by taking fluoride supplements, can cause fluorosis, which affects the teeth and bones.
(See also Overview of Minerals.)
In the body, most fluoride is contained in bones and teeth. Fluoride is necessary for the formation and health of bones and teeth.
People who live in areas where the drinking water has a naturally high fluoride level may consume too much fluoride—causing a condition called fluorosis. Children who take an high dose of a fluoride supplement can also develop fluorosis, even if they live in an area where the drinking water does not contain fluoride.
Fluoride accumulates in teeth, particularly permanent teeth. Chalky white, irregular patches appear on the surface of the tooth enamel. The patches become stained yellow or brown, causing the enamel to appear mottled. The teeth may also become pitted. These defects appear to affect appearance only and may even make the enamel more resistant to cavities.
Fluoride also accumulates in bones. Rarely, consuming too much fluoride for a long time results in dense but weak bones, abnormal bone growths (spurs) on the spine, and crippling due to calcium accumulation (calcification) in ligaments.
The diagnosis of fluoride excess is based on symptoms. Blood tests to measure fluoride levels may be available.
Treatment of fluoride excess involves preventing further accumulation of fluoride by reducing fluoride consumption. For example, if people live in areas with high fluoride levels in the water, they should not drink fluoridated water or take fluoride supplements. Children should always be instructed not to swallow fluoridated toothpaste.
