Fluoride is the term for the ionized form of the element fluorine, as it occurs in drinking water. The two terms , fluorine and fluoride, are used interchangeably.
Adult human contains less than 1.4 mg of fluorine most of which is in the bones and teeth. In small amount, fluorides help develop strong bones and teeth, but in excessive amounts, bones become porous and soft and teeth become mottled and easily worn down.
A proper intake of fluorine is essential for maximum resistance to dental caries, a beneficial effect that is particularly evident during infancy and early childhood, and which is persistent through adult life.
Functions of fluorine
- Fluoride ions at proper levels of intake, assst in the prevention of dental caries.Children under five years of age consume drinking water containing one ppm of fluorine, the teeth have fewer dental caries in childhood, adolscence and throughout life.
- Dietary fluorineÂ is essentialÂ for otimal bone structure and for prevention of osteoporosis in humans. Hence, some doctors use fluorine therapeutically in the treatment ofosteoporosis in aged.
- Defeicency of fluorine results in excess dental caries. alsoÂ there is indication that its deficiency results in osteoporosis in the aged. However, excess of fluorine is of more concern than its defciency.
Fluorine is a cummulative poison; hence, chronic fluorine toxicity, known as fluorosis.
The enamel of the teeth is likely to lose lustre and become chalky and mottled when one of the following conditions prevail:
- When the fluoride content of the drinking water exceeds 2.5 ppm.
- When the amount of fluorine ingested exceeds 30 to 40 ppm of the dry matter of the diet.
- when a person consumes (in food and water) fluorine in excess of 20 mg/day over an extended period of time. The degree of mottling depends on the level of fluorine intake and individual suspectibility. Mottling of teeth in children has been observed if fluoride concentrations in the diet and drinking water are 2 to 8 ppm.
Fluorosis also affect the bones. they lose their normal colour and lustre, become thiockened and softened, and break more easily.
Sources of fluorine
Fluorine is widely but unevenly distributed in nature. It is found in many foods, but seafood and tea are richest dietary sources.
The fluorine content of food varies widely and is affected by the fluoride content of environment (air, soil and water) in areas in which they are produced.