November 18, 2019

Fluoride in water is safe and effective

It is unprecedented in my 11 years as Maine’s public health director that with very short notice more than 30 of Maine’s major health care, public health, and dental health organizations stood together to proclaim our support for community water fluoridation to prevent tooth decay and dental disease.

With a 62-year history of safety and efficacy in preventing tooth decay, fluoridation was declared by the U.S. Centers for Disease Control and Prevention as one of the 10 most successful public health achievements of the 20th century.

In light of recent concerns arising from misinformation about fluoride disseminated in some Maine communities, we felt we must reassert our long-standing support for this basic public health measure.

First, there are a few basic questions that are worth reviewing. What is fluoride? It is the ionic form of fluorine, one of the most common elements found on earth, and occurs naturally in many waters.

What does community water fluoridation do? It adjusts the natural fluoride levels in water supplies to those that are most beneficial to dental health. Studies continue to show fluoridation of community water is the single most effective way to prevent tooth decay, and does so by 20 to 40 percent. As the most common chronic disease of childhood, tooth decay can result in a lifetime of ill health, including infections and heart disease.

How does fluoride work? When ingested through drinking water, fluoride appears in frequent low-dose concentrations in saliva and plaque, and in turn inhibits the breakdown of enamel, improves the recovery of damaged enamel, and reduces the activity of bacteria that causes tooth decay.

Second, there is misinformation regarding fluoridation that warrants responses.

Some say fluoride is mass medication. Fluoridation of community water supplies is analogous to adding folic acid to wheat products to prevent birth defects, iodine to salt to prevent hypothyroidism, chlorine to water to disinfect it, and vitamin D to milk for bone health. These are all public health measures.

Some say European countries are discontinuing community water fluoridation. A number of European countries choose to add fluoride to their salt rather than their water. Salt fluoridation can be as effective as water fluoridation. Therefore, these countries are fluoridated – simply by using salt rather than water.

Some say the National Research Council report from March 2006 indicates fluoride should not be mixed with our water supply. This is a misrepresentation. There is nothing in this report that examines or calls into question the safety of community water fluoridation.

Some say the American Dental Association’s report from November 2006 does not support giving fluoride to infants. This is also a misrepresentation. This report does not examine or call into question the safety of community water fluoridation. The report addresses some simple and effective ways to reduce fluoride intake in those infants whose diets is primarily from reconstituted infant formula made with fluoridated water and whose parents may be concerned about a possible increased risk of fluorosis (cosmetic mottling) before permanent teeth have formed. The American Dental Association continues to recommend fluoridation of community water, and recognizes that the occasional use of optimally-fluoridated water will not harm a baby’s developing teeth.

Some say fluoride is poison. A statement like this ignores the fact that poison is usually a matter of dose. Large doses of most substances, including pure water, can “poison” people. The fact that iron in large amounts is harmful does not prevent us from using it as a supplement to the iron found naturally in our diet. Likewise, the amounts of fluoride contained in fluoridated community water are not poisonous, and in fact, are very beneficial.

Some have tried to make a link between fluoride and autism. We know of no link, and the Autism Society of Maine states (March 2007), “We have seen no direct research connection between fluoride and autism.”

Some have tried to make a link between fluoride and cancer. However, the American Cancer Society states emphatically, “Scientific studies show no connection between cancer rates in humans and adding fluoride to drinking water.”

Some have tried to make a link between fluoride and brittle bones. However, Clifford J. Rosen, MD, Director of the Maine Center for Osteoporosis Research and Education thoroughly addressed this claim in a piece published by this newspaper on March 21.

Community water fluoridation continues to have a long-standing track record of safety and efficacy in addressing one of the most common preventable health issues of our children – dental disease. For the sake of our children and their future, please stand together with Maine’s major health organizations in support of community water fluoridation.

More information on fluoride can be found on the Maine CDC’s Web site at

Dora Anne Mills, MD, MPH, is the director of the Maine Center for Disease Control.

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