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Fluoride

A fluoride is a binary compound of fluorine with another element or radical. It can also be defined as a salt of hydrofluoric acid[?]. Fluoride ions (F-) are regarded as a probable essential element for humans but their use in low concentrations in dental healthcare products and especially in drinking water systems is controversial. It is feared by some that the addition of certain fluorides into drinking water supplies may be a public health danger, because high levels of these fluorides are toxic and free fluorine from the added fluorides may form toxic fluoride compounds. Sodium fluoride is used as an insecticide, in bait form.

Fluoride and dental health

Fluoride compounds are naturally found in drinking water and some foods. Fluoride ions replace hydroxyl ions in hydroxyapatite[?] in teeth, forming fluorapatite[?], which is more chemically stable and dissolves at a pH of 4.5, compared to 5.5 pH for hydroxyapatite. This is generally believed to lead to fewer cavities, since stronger acids are needed to attack the tooth enamel.

For this reason, fluoride compounds such as sodium fluoride[?] (NaF), sodium monofluorophosphate[?] (SMFP), stannous fluoride[?] (SnF2) or amine fluoride[?] are often added to toothpaste. A common view of many dentists and health organisations is that fluorides should also be added to municipal water supplies where the natural level is less than 0.7 ppm in water, to increase the concentration to between 0.7 and 1.2 ppm, with studies showing that incidence of dental cavities is much less where the water is fluoridated up to 1 ppm. Many cities worldwide add fluoride to their water supplies, citing its effectiveness, safety and low cost.

A dissenting view, supported by other scientific studies, suggests that the use of fluorides, particularly silicofluorides (H2SiF6 and Na2SiF6), has contributed to adverse health and behavioral effects. A high level of fluoride, over 2 ppm in water, has been implicated as a possible contributing factor in many cases of fetal damage, dental fluorosis, weakened bones and Alzheimer's Disease. Other studies also suggest that even lower fluoride levels may be causing an increased incidence of elevated lead levels seen in children's blood, and higher violent crime rates associated with lead neurotoxicity.

Attempts to fluoridate the population via the water supply cannot take into account the differences in the amount of water that individuals drink, or each individual's reaction the fluoride.

A review by the NHS Centre for Reviews and Dissemination in 2000 concluded that fluoridation reduced the prevalence of dental caries, and increased prevalence of dental fluorosis, but that "research evidence is of insufficient quality to allow confident statements" about other effects.

Critics of fluoridation charge that fluoride is deliberately associated with good health to protect many major industries, especially steel smelting, from the massive lawsuits that began to be filed in the 1930s for fluoride related damage to livestock, farms, and community health.

The controversy over fluoridation's effect on the public health is unlikely to end soon. Currently there is no way to reduce the fluoride emissions from the metal smelting and processing industries to non-toxic levels without shutting them down entirely.

Fluoride Poisoning

Salts of fluorine are toxic if swallowed or inhaled. Contact with skin or eyes is also dangerous. In case of accidental swallowing, give milk, calcium carbonate or milk of magnesia[?] to slow absorption. Eye or skin contact should be treated by removing any contaminated clothing and flushing with water.

The lethal dose for sodium fluoride is about 75 mg per kilogram body mass, or about 5 grams for an average person.

see History Donora, Pennsylvania Fluoride poising from Zinc Works.

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