What You Need To Know About Fluoride in Water

Nearly three-quarters (72.3%) of the United States population has access to fluoridated community water systems. Communities with added fluoride in water see lower rates of cavities among children and adults—about 25% lower.

Adding fluoride to drinking water “is seen as one of the leading public health measures,” Dr. Mark Wolff, Dean of the University of Pennsylvania School of Dental Medicine, recently told Food & Wine magazine, “saving millions of dollars in dental care and decay and pain in people of all ages.”

However, the debate over fluoride in public water systems has never completely ended, and debates about it are again making headlines.

Dr. Joan Gluch is the Division Chief of Community Oral Health at Penn Dental Medicine. She directs community health service learning courses at PDM. She also oversees the clinical outreach programs PennSmiles, the dental program at Mercy LIFE, and Puentes de Salud. Her ongoing research focuses on expanding access to oral health promotion and clinical care in community-based settings.

In the video above, Dr. Gluch answers some common questions about fluoride in water. Watch the video, then keep reading for more information about this important issue.

Why Is Fluoride in Water?

Fluoride is a mineral naturally found in water. Other natural sources of fluoride include soil, air, and some foods (for example, spinach and grapes). But the natural levels of fluoride ions in water aren’t sufficient to prevent cavities (dental caries).

When communities add a small amount of fluoride to their drinking water—typically around 0.7 milligrams per liter (mg/L) (or one ten-thousandth of a teaspoon)—they consistently see fewer cavities in people of all ages. The fluoride in the water reinforces tooth enamel, making teeth more resistant to decay.

What Are the Benefits of Fluoride in Water?

The main benefit of fluoride treatment in public water systems is reduced tooth decay. “We’ve been able to help individuals keep their teeth longer because of the health benefits of water fluoridation,” says Dr. Gluch.

In addition, fluoridated water is an extremely cost-effective way to deliver fluoride’s cavity-preventing benefits. “For most municipalities, every $1 invested in water fluoridation saves $38 in dental treatment costs,” according to the American Dental Association.

And unlike fluoride toothpastes, which depend on individual usage, community water fluoridation benefits everyone, regardless of socioeconomic status.

“Easy access [to fluoride treatment] is especially important for those who aren’t able to visit the dentist, buy fluoride toothpaste, or access all the dental activities needed to prevent cavities,” says Dr. Gluch.

Does Fluoride Have Any Adverse Effects?

Overexposure to fluoride, at levels far greater than those in fluoridated public water systems, can cause fluorosis.

Dental fluorosis is a discoloration of teeth. It isn’t painful and doesn’t affect the teeth’s function, and cosmetic treatments easily correct it.

Skeletal fluorosis, a chronic bone disease, is more serious. It can lead to osteoporosis, arthritis, and chronic joint pain. However, it occurs after years of persistent overexposure to fluoride.

Environmental Protection Agency (EPA) regulations currently set the maximum allowable amount of fluoride in public drinking water systems at 4.0 mg/L. That primary standard protects against the risk of skeletal fluorosis while preserving access to the benefits of fluoride in water.

The EPA’s recommended secondary safety standard, to guard against cosmetic effects like dental fluorosis and aesthetic effects like water’s taste, color, and odor, is 2.0 mg/L.

Because fluoride treatment of water is a local decision, most communities set their limit far lower, at the recommended optimal level of 0.7 mg/L. Some set it lower still.

Does Fluoride in Drinking Water Affect IQ in Children?

A research review by the National Toxicology Program concluded “higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children.”

Research into this question continues. However, the studies reviewed often involve greater fluoride levels than those generally found in the U.S. “The studies conducted in Mexico and Canada,” Dr. Gluch points out, “had much higher levels—2.5 parts per million, 5 parts per million.”

“We make decisions based on the evidence,” she adds, “so that our clinical care is guided by the best research studies. And the studies that show any potential cognitive effects just don’t meet those high standards.”

Why Have Some Countries Ended Public Water Fluoridation?

While the U.S. has a long history of funding safe and effective municipal water systems, not all countries do. In addition, other nations take different approaches to public oral health—adding fluoride to salt or milk, promoting healthy meals, or providing free or low-cost dental care.

Dr. Gluch notes that in 2011, Calgary, Canada banned water fluoridation. “In five years, cavities among elementary school children increased almost twofold. Calgary ended up putting fluoride back in the water in 2021.”

She says, “Taking away a proven measure to prevent dental decay is going to have consequences in communities, especially those who may lack access to dental care or may not have enough dentists, especially to provide care to low-income individuals.”

Should Fluoride in Water Be an Individual Choice?

Because fluoride is a naturally occurring mineral, almost everyone is exposed to some level of it. “Although our society respects individual rights,” Dr. Gluch says, “we weigh them carefully when there’s a benefit for the common good.”

“We have a very practical experience base with a tried-and-true preventive measure that has strong scientific evidence at the recommended levels,” notes Dr. Gluch. “Again, I’m talking about very small amounts—seven parts per million. That makes such a difference in less cavities and better oral health for everyone in our communities.”

For proven ways to achieve and maintain your best dental health, see the dental professionals at Penn Dental Family Practice. Schedule your appointment online or call us at 215-898-PDFP (7337).