Should You Use PFAS-Free Dental Floss?

Part of overall good health includes having good oral health. We think of flossing as a healthy habit—but previous research has found that a certain type of dental floss contains harmful chemicals that may be leaching into our bodies.

According to a 2019 study published in the Journal of Exposure Science & Environmental Epidemiology, women who flossed with Oral-B Glide dental floss and other brand dental flosses had higher levels of perfluoroalkyl substances (also known as PFAS) in their blood than those who didn't. Tests also confirmed that the company's Glide floss—along with several of its competitors—contained fluorine, a marker of PFAS chemicals.

That's concerning, researchers said, since those same compounds have been linked to serious health problems like cancer, fertility issues, and weight gain. But how worried should we be, exactly, about our nightly dental care routine? Here's what we know.

What Are PFAS?

PFAS are a common class of chemicals that can help make substances water-and grease-proof. Because of that, they're present in a lot of consumer goods—like fast-food wrappers, Teflon and other non-stick cookware, flame-retardant fabrics, and water- and stain-resistant clothing, to name just a few. People are exposed to PFAS through the products we use and the foods we eat, and also through household dust and contaminated drinking water.

PFAS are known as "forever chemicals" because they tend to remain in the human body and environment indefinitely. Decades of research have linked PFAS to health issues like cancers, liver and thyroid diseases, prenatal and development issues, and immunosuppression. The concern is heightened enough to have led the Environmental Protection Agency (EPA) to release a Strategic Roadmap plan "to confront PFAS contamination nationwide" in October 2021. Among other efforts, the plan aims to limit PFAS in drinking water—the first major step by a federal regulatory body to clean drinking water systems and hold manufacturers accountable.

The Journal of Exposure Science & Environmental Epidemiology study mentioned above is the first time, however, that the chemicals have been linked to flossing. The study authors said their findings shed new light on how these chemicals end up in our bodies, and how we can limit our exposure by modifying our behavior and making smarter choices when we shop.

What Did the Study Find?

In the study, researchers took blood samples from 178 middle-aged women—half white, half African American. They also interviewed the women about nine behaviors they thought could be linked to higher PFAS exposure, including regular flossing and fast-food consumption. (They had a hunch that dental floss might be problematic since some types had been described as Teflon-like.)

They found that women who flossed with Oral-B Glide—which "slides 50% more easily in tight spaces," according to the company's website—tended to have higher levels of a PFAS compound called perfluorohexanesulfonic acid, or PFHxS. Out of the 18 dental flosses tested, six brands were found to contain detectable levels of fluorine, a marker of PFAS.

Two store-brand floss products with "compare to Oral-B Glide" labeling and another brand that described itself as "Teflon fiber" also tested positive for fluorine.

Unsurprisingly, living in a city with PFAS-contaminated drinking water—and living in a house with stain-resistant carpets or furniture—were also linked to higher PFAS levels in the blood. Among African Americans, frequently eating food prepared in coated cardboard containers (like French fries and take-out) was also linked to higher levels.

Why Exactly Should You Worry About PFAS?

Previous research suggests that adults with higher levels of PFAS in their blood are at greater risk of kidney and testicular cancer, high cholesterol, fertility problems, and ulcerative colitis. Elevated PFAS levels are linked to other detrimental effects including lower birth weights in newborns and to thyroid disease, compromised immunity, and lowered sex and growth hormones in children.

One study published in PLOS Medicine in 2018 found that women with higher levels of PFAS tend to have slower metabolisms and gain back more weight after dieting than those with lower levels. However, this wasn't true for men, and researchers suspect that the chemicals' effects on female sex hormones may be responsible.

Scientists have known for years that PFAS are present in many consumer products. But more and more, studies are showing that there is a connection between using these products and a "higher body burden" of PFAS, said lead author Katie Boronow, a staff scientist at the Silent Spring Institute. "In other words, these chemicals don't stay put in products—they migrate out and into people's bodies," Boronow told Health. "And the more you're exposed, the higher the levels in your body."

Should You Stop Flossing?

No one is saying we should stop flossing. First of all, we know it's good for us. And even if flossing with Oral-B Glide is directly responsible for elevated PFAS levels, other studies are needed to confirm this association.

In their paper, the authors wrote that floss products containing PFAS "are widely available, but that consumers can use advertising claims to help identify them." In other words, you can avoid PFAS by avoiding Oral-B Glide floss, or any floss that's marketed for its "glide ability".

We know what you're thinking: No, regular floss doesn't feel as nice on your teeth and gums. But in Boronow's opinion, reducing your chemical exposure may be worth the trade-off. "Our study found that safer flosses are available, so people can choose to use dental flosses without PFAS," said Boronow.

In January 2019 the American Dental Association (ADA) released a statement that warned that the Journal of Exposure Science & Environmental Epidemiology study "may raise unwarranted concern about the safety of certain types of dental floss" by continuing to encourage people to clean between their teeth daily.

The Association said the ADA Science Institute found the study data "insufficient to support the conclusions presented," pointing out that among the study's shortcomings was that they measured a marker for PFTE, even though the women in the study who reported using Glide were found to have elevated levels of PFHxS.

How Worried Should You Be?

The truth is, we all have PFAS in our bodies—from lots of different sources—and it's smarter to focus on avoiding future exposure rather than worry about what's already happened.

Take non-stick cookware, for example. Tom Brutton, PhD, a fellow and PFAS researcher at the Green Science Policy Institute, told Health that consumers don't have to throw out pots and pans they already own—but that they shouldn't stock up on new Teflon products, either.

"The exposure to you from your use of that pan isn't going to be so huge that it represents a significant health threat," said Brutton. "But when it's time to buy a new one, perhaps look for one that doesn't contain PFAS."

Floss isn't nearly as expensive as an entire set of cookware, so if you'd rather be safe than sorry, it probably won't hurt—not much, at least—to toss your current stash and start fresh.

"We have confirmed none of the substances in the report are used in our dental floss," an Oral-B spokesperson told Health in an email. "The safety of the people who use our products is our top priority. Our dental floss undergoes thorough safety testing and we stand behind the safety of all our products."

As far as the study authors are concerned, their advice for people who want to limit their exposure to harmful chemicals is to use dental floss without PFAS and search for other ways to protect themselves from harmful chemicals in everyday products. Remember that not all coated flosses contain PFAS. You can check with manufacturers to figure out whether the floss you use contains PFAS.

Overall, Boronow said, this study lends more evidence to the idea that consumer products are an important source of PFAS exposure. "Because there are so many sources of PFAS, and every exposure adds up, any steps that people can take to reduce their exposure is a good thing."