Fluoride is a naturally occurring element that helps prevent tooth decay.

The decrease in tooth decay over the second half of the 20th century in many industrialized countries is due to fluorides. The World Health Organization reports that “there is clear evidence that long-term exposure to an optimal level of fluoride results in diminishing levels of tooth decay in both children and adults.”

A mix of topical and systemic fluorides is important, which is why most dentists and dental organizations around the world recommend both public fluoridation programs as well as brushing once or twice a day with a fluoride toothpaste.

What is Fluoride?

Fluoride is a natural mineral found throughout the earth’s crust and widely distributed in nature. Some foods and water supplies contain fluoride.

Fluoride helps prevent tooth decay by strengthening the hard outer layer of teeth, called the enamel. The World Health Organization has endorsed the use of fluoride because of its effect on tooth decay.

Fluoride is available in two forms: topical and systemic. Topical fluorides, such as fluoride toothpastes, rinses and varnishes, are applied directly to teeth already in the mouth, making them more decay-resistant.

Systemic Fluorides

Systemic fluorides are those that are ingested into the body and become incorporated into newly forming teeth. The primary sources of systemic fluoride are water fluoridation, milk fluoridation and salt fluoridation.

When you swallow fluoride in water, salt, milk or other foods, it gets absorbed into your bloodstream and deposited throughout your body, including throughout the surface of newly growing teeth. More importantly, it shows up in saliva, which continually bathes your teeth, providing a constant source of fluoride that strengthens the enamel surface of teeth and protects against decay.

What is Milk Fluoridation?

The addition of fluoride to milk and milk-based products is called milk fluoridation. The World Health Organization has supported milk fluoridation as an alternative to water fluoridation. Fluoride in milk directly targets children. Milk fluoridation is most efficient at reducing cavities when it starts in early childhood and continues for at least 180 days in a year.

Is Milk Fluoridation Safe?

In a review on safety, milk fluoridation was reported to be safe and fluorosis, if any, was mild2. No other adverse effects have been reported.

What is Salt Fluoridation?

The addition of fluoride to table or household salt by salt manufacturers is called salt fluoridation. Fluoride in salt can reduce cavities substantially. Studies have consistently shown a significant reduction in cavities in countries adopting salt fluoridation, including Switzerland, Mexico, Hungary, Jamaica and Cuba. In 1994, the Pan American Health Organization launched a multi-year drive to support implementation of salt fluoridation, with positive results.

Is Salt Fluoridation Safe?

Salt fluoridation is considered an inexpensive, safe and effective means of preventing tooth decay. However, a big challenge with the use of salt fluoridation is avoiding multiple sources of fluoridation in a particular country or region3. The combination of both salt and water fluoridation is not recommended.

What is Water Fluoridation?

Fluoride is often added to drinking water to help reduce tooth decay. In the 1930s, researchers found that people who grew up drinking naturally fluoridated water had up to two-thirds fewer cavities than people living in areas without fluoridated water. Studies since then have repeatedly shown that when fluoride is added to a community’s water supply, tooth decay decreases.

How do I know if my Water is Fluoridated?

If your water comes from a public water supply, you can find out if it’s fluoridated by contacting your local water district, health department or Ministry of Health in your country.

Is Water Fluoridation Safe?

Studies conducted over the past 65 years have consistently shown that fluoridation of community water supplies is both safe and beneficial. Except for fluorosis, water fluoridation is not associated with any other adverse side effects1.

Portions of this article have been sourced from research and articles by the American Dental Association.

Parnell C, Whelton H, O'Mullane D. European Archives of Pediatric Dentistry. 2009;10(3):141-148.

Yeung CA. Evid Based Dent. 2008;9(2):39-43.

Marthaler T, Petersen P. International Dental Journal 2005;55:351-358