Fluoride is nature's cavity fighter and occurs naturally in varying amounts in water sources such as rivers, lakes and even the oceans. Fluoride is naturally present to some extent in certain foods and beverages but the levels vary widely. To help protect teeth from cavities, fluoride is also added to some dental products such as toothpaste.

Fluoride benefits both children and adults. Here's how:
Before teeth break through the gums (erupt), the fluoride taken in from foods, beverages and dietary supplements makes tooth enamel (the hard surface of the tooth) stronger, making it easier to resist tooth decay. This provides what is called a "systemic" benefit.

After teeth erupt, fluoride helps rebuild (remineralize) weakened tooth enamel and reverses early signs of tooth decay. When you brush your teeth with fluoride toothpaste, or use other fluoride dental products, the fluoride is applied to the surface of your teeth. This provides what is called a "topical" benefit.

In addition, the fluoride you take in from foods and beverages continues to provide a topical benefit because it becomes part of your saliva, constantly bathing the teeth with tiny amounts of fluoride that help rebuild weakened tooth enamel.

Community water fluoridation is simply the addition of fluoride to drinking water to increase the natural fluoride level up to the recommended level that helps prevent cavities. Almost 75 percent of the U.S. population is served by fluoridated community water systems as of 2012.

Communities fluoridate their water supply because it is a cost-effective public health method that helps prevent cavities. The average cost per year for U.S. communities to fluoridate the water ranges from $.50 per person for large communities to $3.00 per person for small communities.

Cavities are caused by a disease called "caries," which is five times more common than asthma and seven times more common than hay fever in 5-to-17-year-olds. The pain from untreated cavities can cause people to lose sleep, have trouble eating, speaking and paying attention at school or work.

A report from the U.S. Surgeon General in 2000 estimated that 51 million school hours are lost per year because of dental-related illness. Without water fluoridation, that number would likely be much higher.

The American Dental Association (ADA) supports community water fluoridation as the single most effective public health measure to prevent tooth decay. Studies prove water fluoridation continues to be effective in reducing dental decay by at least 25% in children and adults, even in the of era widespread availability of fluoride from other sources, such as fluoride toothpaste.

The ADA, the American Medical Association, the World Health Organization and many others support fluoridation of community water supplies. The U.S. Centers for Disease Control and Prevention (CDC) has cited community water fluoridation as one of 10 great public health achievements of the 20th century (along with vaccinations, infectious disease control and motor vehicle safety).

So, by simply drinking fluoridated water, you are doing something good for your oral health.

Water fluoridation is safe, effective and healthy. Seventy years of research, thousands of studies and the experience of more than 210 million Americans tell us that water fluoridation is effective in preventing cavities and is safe for children and adults.

No. Fluoride in water at the recommended level is not toxic according to the best available scientific evidence.

Toxicity is related to dose. While large doses of fluoride could be toxic, it is important to recognize the difference between the effect of a massive dose of an extremely high level of fluoride versus the fluoride level currently recommended for public water systems. Like many common substances essential to life and good health - salt, iron, vitamins A and D, chlorine, oxygen and even water itself - fluoride can be toxic in massive quantities.

Fluoride at the much lower recommended concentrations (0.7 mg/L) used in community water fluoridation is not harmful or toxic.

The single dose (consumed at one time) of fluoride that could cause acute fluoride toxicity is 5 mg/kg of body weight (11mg/kg of body weight of sodium fluoride). This dose is considered the probably toxic dose (PTD) which "is defined as the minimum dose that could cause serious or life-threatening systemic signs and symptoms and that should trigger immediate therapeutic intervention and hospitalization." Acute fluoride toxicity occurring from the ingestion of optimally fluoridated water is impossible. With water fluoridated at 1 mg/L, an individual would need to drink five (5) liters of water for every kilogram of body weight. For example, an adult male (155 pound/70.3 kilogram man), it would require that he consume more than 350 liters (nearly 93 gallons) of water at one time to reach an acute fluoride dose. With optimally water now set at 0.7 mg/L, it would take almost 30% more, or nearly 120 gallons (more than 1,900 eight ounce glasses) of water at one time to reach the acute dose.

Sources:

U.S. Department of Health and Human Services. Federal Panel on Community Water Fluoridation. U.S. Public Health Service recommendation for fluoride concentration in drinking water for the prevention of dental caries. Public Health Rep 2015; 130(4):318-331. Article at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4547570. Accessed August 9, 2010.

Whitford GM. Acute toxicity of ingested fluoride. In Buzalaf MAR (ed): Fluoride and the Oral Environment. Monogar Oral Sci. Basel, Karger. 2011; 22:66-80. Abstract at: https://www.ncbi.nlm.nih.gov/pubmed/21701192. Accessed August 9, 2010.

• Read the American Dental Association's Fluoridation Facts.
• Review Evidence-Based Clinical Practice Guidelines related to fluoride and fluoridation.
• Visit the Centers for Disease Control and Prevention.
• Visit the American Academy of Pediatrics' Campaign for Dental Health website.

JAMA releases study on elimination of community water fluoridation

Removing fluoride from U.S. public water systems would increase tooth decay by 7.5% and cost at least $9.8 billion over five years, according to estimates in a study published by the Journal of the American Medical Association Health Forum. The study, released May 30, seeks to determine the oral health outcomes for children and associated health care costs when water fluoridation stops. 

Read more on ada.org