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FLUORIDE
The trace element fluorine is present in the body almost entirely in bone and
teeth. Because of its high reactivity, fluorine exists as its anion fluoride.
Fluoride's best known effect is to serve as a catalyst for both the
mineralization of developing tooth enamel prior to tooth eruption and for
remineralization of surface enamel. The combination of these fluoride effects
greatly reduces occurrence of dental decay (caries). Denotal caries is an
infectious disease caused by bacteria. When food is ingested, oral bacteria
multiply within their home (plaque) and produce organic acids. Loss of tooth
enamel accelerates as long as plaque pH is less than 5.5. The presence of
fluoride changes some of the tooth crystal into a less acid-soluble crystal
known as fluoropatite.
Diet recommendations: The Food and Nutrition Board of the
National Academy of Sciences has concluded that a fluoride intake of 0.05 mg/kg
body weight, after the age of 6 months, provides an adequate fluoride intake to
reduce risk of dental decay. It is assumed that this fluoride will come from a
combination of food and water sources.
Food sources: The major source of fluoride is drinking
water. Seafood, some teas, and foods made with mechanically separated chicken
(baby food, canned meats, luncheon meats, and frankfurters) contribute to total
fluoride intake. Otherwise, most foods are very low in fluoride.
Clinical uses: Regular comsumption of fluoride from a
community water supply plus regular use of fluoridated toothpaste can
significantly decrease prevalence of dental decay. Dietary fluoride supplements
are only recommended for children when the water supplies fluoride at less than
0.3 mg/L. In this case, fluoride supplements of 0.25 mg/day for ages 0.5-3
years, 0.5 mg/day for ages 3-6 years, and 1 mg/day for ages 6-16 years can be
recommended. No dietary fluoride supplement is recommended when water supplies
fluoride at greater than 0.6 mg/L.
Under controlled experimental conditions, slow release administration of
fluoride (23 mg/day) plus calcium has been shown to stimulate new bone formation
in some individuals.
Toxicity: Children less than 8 years of age can develop
mottled tooth enamel (white horizontal lines with hypo-mineralized areas
susceptable to decay in extreme cases) if they ingest several times more
fluoride than recommended during tooth enamel formation. Swallowing of
fluoridated toothpaste by young children has been shown to be the most prevalent
cause of this problem. |
