fluorideMost people are very familiar with the word fluoride. We hear it in toothpaste commercials and know it’s in the water most city dwellers drink. Scientists tell us fluoride helps fight cavities. How does it help fight cavities, though, and why, in 1945 did Grand Rapids, MIchigan become the first city in the world to introduce fluoride to its municipal water supply? We will answer those questions here.

What Is Fluoride?

Fluoride is an inorganic, monatomic anion with the chemical formula F- whose salts are typically white or colorless. The fluoride ion comes from the element fluorine which is the thirteenth most abundant element in the earth’s crust. Fluoride is never found in isolation, however, only in combination with other elements in rocks and soil. When water passes over those rocks, traces of fluoride go into solution which is why fluoride is present in all water sources on earth.

Fluoride, when ingested, helps to strengthen teeth when they are developing. It also initiates remineralization of tooth enamel, allowing teeth to repair themselves when cavities occur. Some scientists believe that it also hinders the ability of plaque to produce the kinds of acid that cause cavities. In both of these ways, fluoride acts to stop tooth decay while it is still in its initial phase, limiting the formation of cavities.

Why Put Fluoride in Water?

On January 25, 1945, Grand Rapids, Michigan was the first city worldwide to introduce fluoride to its water supply. The city agreed to be part of a great experiment on the benefits of fluoridation. It was selected because it had a low level of fluoride naturally occurring in its water, a capable water filtration plant, and large population of school age children who suffered from a terribly high rate of dental caries. At six years of age, 80 percent of children had an average of 14 cavities. Nationwide, half of Americans in the 1930s needed dentures by the time they were 55 years old.    

The results of this 15-year study revealed a 60-65% reduction in dental caries, and so many other cities, including the control city in the experiment, Muskegon, made the choice to add fluoride to their own water supplies. Today approximately 64% of Americans drink fluoridated water and very few adults need full dentures at the age of 55.

How Much Fluoride Is in Our Water?

The amount of fluoride varies. If you access your water from a city water system, the city has to decide how much fluoride is optimal for dental health without presenting a risk to other systems. In the United States that amount ranges from .7 to 1.2 parts per million (ppm).

In 2011 the U.S. Department of Health and Human Services proposed lowering the recommended level of fluoride in municipal water systems to .7, stating that too much fluoride causes spots on the teeth of some children.

If you do not have fluoridated water, it’s especially important for you to use a good toothpaste with fluoride in order to protect your teeth. Talk to your dental hygienist at your next routine cleaning about the options you might have to help reduce plaque and prevent cavities from forming in your teeth.