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Fluoride & Fluoridation in Dentistry

One of the ten most important public health measures of the 20th century

By Dr. Amid I. Ismail

Fluoride in dentistry.

How the Story Starts...

It is 1901; Dr. Frederick McKay has just arrived in Colorado Springs to start his dental practice. Unbeknown to him this move will begin a new quest to understand why so many of his patients in the area have a mysterious brown staining of their teeth. McKay will spend thirty years diligently investigating the cause, but in the process he will find that the strangely stained or “mottled” teeth are also decay free. He will go on to establish that the cause is in the drinking water. In 1931, H.V. Churchill, a chemist working for the Alcoa Company, is concerned about a possible link between bauxite, an aluminum ore, and tooth staining. After analyzing water from several associated areas he finds that fluoride is the common factor.

One In A Million

Teeth whitening before.
Dr. H. Trendley Dean studied fluoride in 1931.

Now here's where it starts to get interesting. In 1931 Dr. H. Trendley Dean, a public health dentist working for the U.S. Public Health Service, sets out to study the harmful effects of fluoride but instead, by 1950 he demonstrates that fluoride in small amounts not only has large benefits but its side effects are negligible, a mild staining or “mottling” of the teeth which comes to be known as “fluorosis.”

Dean goes on to suggest that a fluoride concentration of about one milligram per liter (1 mg/L), or 1 part per million (1ppm), in the water supply is associated with substantially fewer cavities but it has no negative health and little aesthetic significance (1ppm is very, very small — about equivalent to a grain of salt in a gallon of water).

A Classic Public Health Study

On January 29, 1945 community trials are conducted to further test the hypothesis that adding fluoride to the water supplies on a population basis will prevent tooth decay. The now famous Grand Rapids, Michigan studies begin; when the results are published in 1950 they show significant reduction in decay. By 1951 “fluoridation” becomes official policy of the U.S. Public Health Service, and by 1960 water fluoridation becomes widely used in the United States. Today 50 years later, it reaches 70% of all Americans.

Now with over sixty years of experience the Center for Disease Control (CDC) has named water fluoridation as one of the ten most important public health measures of the 20th century.

In 1955 the first clinically proven fluoride toothpaste is launched. Today, sodium mono-fluoro-phosphate and sodium fluoride at a concentration of 1000 to 1100 ppm, are the most popular active fluoride ingredients in toothpaste used for prevention of tooth decay. Although other fluoride-containing products are available (as we shall see), water fluoridation remains the most equitable and cost-effective method of delivering fluoride to all members of most communities, regardless of age, educational attainment, or income level.

What's So Magical About Fluoride And Teeth

Dean and his colleagues assumed that fluoride's protection against cavities was because of its incorporation into developing teeth, before they erupt into the mouth — a so-called systemic (through the body) effect. Today, there is general agreement that the predominant effect of fluoride is not systemic, but mainly topical or “local” — at the tooth surfaces. That doesn't mean that water fluoridation is not valid, but it does cast an interesting light on how fluoride acts.

The Right Place at the Right Time

Fluoride must be present in the right place; in the biofilm (dental bacterial plaque) and in the saliva; and at the right time (during sugar exposure) in order to interfere with the caries (decay) process. The process, believe it or not, is a sort of swing and balance affair between acid dissolution (softening or de-mineralization) and re-hardening (re-mineralization) of the tooth surfaces most liable to decay.

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