The science behind community water fluoridation

Q&A with American Fluoridation Society duo on advocacy backed by evidence

A wave of activists has swept across the country, arguing against the merits of community water fluoridation.

 The anti-fluoridation activists counter the recommendations of the leading public health, medical and dental organizations, including the ADA, Centers for Disease Control and Prevention, American Academy of Pediatrics, U.S. Public Health Service and World Health Organization. All of the pro-fluoridation organizations tout the documented evidence that fluoride, a mineral that exists naturally in water supplies, has been shown to reduce the rate of tooth decay when added to water.

Since 1950, the ADA has continuously endorsed optimal fluoridation of community water supplies as a safe and effective public health measure for the prevention of tooth decay. The ADA’s policy is based on the best available scientific evidence on the safety and effectiveness of fluoridation.

The American Fluoridation Society, founded in 2014, often works in tandem with the ADA, state dental societies and other oral health organizations to advocate for the continuance and implementation of community water fluoridation in areas across the nation.

The society is fresh off a win in Leesburg, Florida, where it, along with help from the ADA and other groups and local dentists, successfully advocated for the initiation of community water fluoridation after the municipality went without for two decades.

Johnny Johnson, Jr., D.M.D., American Fluoridation Society president and Florida pediatric dentist, and Matt Jacob, society member who has contributed to the ADA’s guidebook Fluoridation Facts, answered questions about the evidence-based science behind fluoridation and how dental and oral health professionals can counter arguments that come their way.

ADA News: Where does fluoride come from?

AFS: Fluoride is an ion of the mineral fluorine. It is naturally found in almost all soil and water and many rocks. It is released into the environment when rocks or soil containing fluoride are dissolved by water.

ADA News: How did we discover the beneficial effects of fluoride on the teeth?

AFS: A dentist, Dr. Fredrick McKay, who moved to Colorado Springs, Colorado, in 1901, noticed a phenomenon in which patients who were born there or moved in as infants had a brown stain on their enamel that couldn’t be easily removed. It did not occur in adults once their teeth had erupted.  This stain was named the “Colorado brown stain.” Studies demonstrated that children living in areas with higher fluoride had less caries. These astute clinical observations resulted in the birth of community water fluoridation in 1945.  Indeed, fluoridation is replicating what Mother Nature provided to certain communities in America.

ADA News: Why is community water fluoridation needed?

AFS: Community water fluoridation is the process of adjusting the amount of fluoride in drinking water, up or down, to a level recommended to prevent cavities.  The recommended level is also called the optimal level, 0.7 ppm. Most water contains fluoride at levels that are too low to prevent cavities. Optimal fluoride levels are the amount of fluoride in water that will give the maximum reductions in cavities in adults and children with minimal levels of dental fluorosis.

ADA News: Why is science important when it comes to supporting community water fluoridation?    

AFS: It is important to know the best available science on any topic — whether that be the best way to build a bridge to last 40 years, a home to resist hurricanes or other natural events or public health measures.  High-quality scientific studies are the way to build a consensus on what the overwhelming preponderance of credible scientific research supports. The persistent research and search for what caused low cavities in certain communities led to the discovery of fluoride’s benefits to the health of teeth. The observation of low cavities and good-looking teeth led us to the optimal amount of fluoride that reduced cavities without unwanted brown stains. Ongoing research is conducted on the effectiveness and safety of fluoridation. Nearly 7,000 research papers and articles are listed on PubMed on water fluoridation. Vaccinations and water fluoridation are two of the most researched public health measures ever.

ADA News: How does the fluoride in community water fluoridation prevent cavities?

AFS: Fluoride gets incorporated into the developing dental enamel of permanent teeth before it erupts into the mouth, enhancing the tooth's resistance to acid breakdown and preventing cavities later in life. This occurs up until the age of 8 years old. Fluoridated water and fluoride toothpaste work together to prevent cavities. Fluoridated water keeps a low level of fluoride in the mouth all day. Fluoride toothpaste provides a much higher concentration at important times of day (e.g., bedtime). Both types of fluoride strengthen the outer tooth enamel and slow the activity of bacteria that cause cavities. Together, the two sources offer more protection than using either one alone.

ADA News: How is fluoride added to water systems?

AFS: Fluoride is added to the drinking water before it leaves the water plant. The existing natural level of fluoride in the water is adjusted to bring it to the optimal level of 0.7 ppm. This is done through precise calculations, and these levels are constantly monitored by water plant personnel with sophisticated equipment. These procedures must meet standards set by the state’s department of natural resources. As the level of water flow and fluoride concentration fluctuates during the day, adjustments in the amount of fluoride added is also adjusted to maintain the optimal level. The way fluoride is added to the water at water plants is the same regardless of the fluoride additive used. There are three fluoride additives that have been approved by the American Water Works Association and meet the strict requirements of the Environmental Protection Agency for water additives.

ADA News: How do you counter the science and evidence that anti-community water fluoridation activists use in their arguments?

AFS: We carefully analyze the studies or reports that opponents share. By doing so, we usually find a significant problem with the methodology. For example, many studies that are circulated by opponents tested natural fluoride levels in water in China, India or other nations that are far higher than the fluoride levels found in fluoridated tap water. 

For more information on community water fluoridation and ADA advocacy, visit resources on fluoride in water at ADA.org/fluoride.