I was told that fluoride may prevent tooth decay, but as a parent I also worry about the safety of putting fluoride in public water supplies. Are there any risks associated with exposing children to fluoride?
Water fluoridation first took place in Canada and the United States in the 1940’s. The decision was made to put 1 part per million of fluoride in water. This was based on observations made in the early 1900s, when researchers noted that residents were more resistant to tooth decay when they were from communities in which there were naturally high fluoride levels.
Dental caries in children has been reduced by 50-75% since water fluoridation was first introduced according to prospective field trials and surveys done over recent years. That is an impressive public health achievement one applauded by many dentists and pediatricians, but, to this day opposed by a number of well-meaning activists as a form of “mass medication”.
In a recent economic analysis the CDC reported that every one dollar (US) invested in this preventative measure, would save $38(US) in dental treatment costs.
Dental caries is the result of bacterial action on teeth. Similar to a thick layer of frost accumulating on a park bench overnight, plaque builds up over time and coats the teeth.
The plaque contains bacteria, such as mutans streptococci, which produce acid. This damaging acid results from the interaction between bacteria and carbohydrates.
This acid in turn then erodes and dissolves the calcium-phospahte mineral of the tooth enamel and dentin. If left unchecked, this process of erosion can lead to tooth decay as early as the toddler years. (It is not uncommon for toddlers to get their cavities repaired under a general anesthetic)
However, fluoride inhibits the development of dental caries in three ways enhanced tooth mineralization, reversal of tooth demineralization and inhibition of the acid-producing bacteria responsible for tooth decay. Fluoride gets incorporated into the enamel and replaces the original, more soluble enamel with a harder substance known as fluoroapatite.
Not all communities have fluoride in the public water supply. According to the Center for Disease Control fluoridation census in 2000, community fluoridation is provided to about 57% of the American population. Canadian data is sparse.
By law, fluoride levels in community water supplies cannot exceed 4 parts per million (ppm) and water suppliers are required to notify consumers if the water concentration exceeds 2 ppm. Dental organizations and public health officials have recommended other sources of water whenever water contains more than 2 ppm of fluoride. Well water contains variable amounts of fluoride, ranging from 0 to 7.22 ppm.
Too much fluoride may lead to a condition known as fluorosis of both the teeth and skeleton. The latter is extremely rare; only five cases have been reported in the past 35 years. The effects off excess fluoride on teeth are mainly cosmetic. There may have a lacy marking across the tooth enamel or, in severe cases, there may be pitting and mottling of the teeth. Ironically, teeth in which dental fluorosis is severe, may be more prone to tooth decay because of associated enamel abnormalities.
Opponents of water fluoridation believe that it should be a matter of individual choice. They have raised concerns such as immunodeficiency syndrome, Alzheimer disease, heart disease and Down syndrome, calling for the end to water fluoridation. Some skeptics have even gone as far as suggesting that water fluoridation is a conspiracy, allowing industries to dispose their fluoride waste in public water. Objective, scientific research has failed thus far to establish any links to or associations with the health concerns mentioned above and the use of 1 ppm of fluoride.
Water filters may affect the fluoride content of water. Activated charcoal filters, cellulose filters, reverse osmosis and distillation may all impact the level of fluoride. Water softeners do not change the fluoride content. Pitcher-type carbon filters and faucet mounted filters (such a Brita or Pur) demonstrated negligible effects on the fluoride concentration of tap water.
Dentists have observed an increase in caries where children are exposed to bottled water only. It comes as no surprise given the fact that 20 out of 900 brands of bottled water add fluoride to their product. In the USA the FDA does not require the labels of bottled water to list fluoride concentrations unless fluoride has been added.
Fluoride supplements can be used where there is no water fluoridation. For more detail, see the fluoride supplementation schedule of the American Academy of Pediatrics by going to their web site (www.ap.org). Supplement use by pregnant women is not beneficial in preventing caries in the offspring.
Once or twice yearly professional application of fluoride gel has been associated with a 20 to 40% reduction in caries. An alternative to gels is the twice yearly application of fluoride varnishes, even though it has not yet been officially approved by the FDA as an anticaries agent. Varnishes have been used in Europe and Canada for more than 20 years.
Caution should be exercised when using fluorinated toothpastes especially in very young children. Two-year-olds ingest almost two thirds of the toothpaste used in brushing and seven-year-olds ingest about a third. Rinsing after brushing may also increase toothpaste ingestion. A pea-sized amount of toothpaste weighs 0.4 gram and provides 0.6 mg fluoride. If a very young child brushes his or her teeth with this twice daily, the entire recommended daily intake of fluoride (0.05 mg/kg) can be consumed. Some experts suggest that children under age 2.5 years not use fluoride-containing toothpastes.
For more information on the fluoride content of mineral waters of the world see http://www.pmgeiser.ch/cgi-bin/mineral?sort=f.
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