Glide floss drew legitimate concern after a study linked its use to higher blood levels of certain industrial chemicals called PFAS. But the landscape has shifted: Oral-B has since reformulated its entire Glide line to eliminate PFAS, replacing the old Teflon-based material with a micro-textured fiber. If you’re using a recently purchased box of Glide, the chemical concern that sparked all the headlines may no longer apply to you.
That said, the story is worth understanding in full, especially if you have older stock or want to make an informed choice about what goes in your mouth every day.
Why Glide Floss Raised Red Flags
Glide floss originally earned its signature slippery feel from PTFE, the same material used in nonstick cookware coatings. PTFE belongs to a broader family of chemicals known as PFAS, sometimes called “forever chemicals” because they break down extremely slowly in both the environment and the human body. These compounds have been linked to liver damage, immune system disruption, developmental problems, and cancer.
A study from researchers at Harvard’s T.H. Chan School of Public Health found that women who flossed with Oral-B Glide had higher blood levels of a specific PFAS compound called PFHxS compared to women who used other types of floss. The researchers also tested multiple floss brands and found that several contained fluorine, a chemical marker indicating PFAS were present. The concern was straightforward: floss sits directly against gum tissue, and flossing often causes minor bleeding, which could give these chemicals a more direct route into the bloodstream than, say, cooking with a nonstick pan.
As one researcher put it, nonstick pans have a larger surface area, but you don’t chew on them the way you do dental floss.
The ADA’s Response
The American Dental Association pushed back on the study’s conclusions, stating it found the data insufficient to support the claims made in the research and the media coverage that followed. The FDA had not issued any restrictions on PTFE-based floss, and the ADA emphasized that people should continue flossing daily with whatever product they prefer rather than stop flossing altogether. Their core message: the proven benefits of flossing outweigh the uncertain risk from chemical exposure.
This is an important distinction. The debate was never about whether flossing itself is harmful. It was about whether one specific material used in one category of floss products added an unnecessary chemical exposure.
Oral-B Removed PFAS From Glide
In a development that got far less attention than the original scare, Oral-B eliminated PFAS from its Glide dental floss line entirely. The Silent Spring Institute, the environmental health organization whose researchers co-authored the original Harvard-linked study, confirmed the change. Oral-B now reports that its updated Glide floss uses a micro-textured fiber and that none of its floss products contain PFAS.
This is a meaningful shift. If you’ve purchased Glide floss recently, you’re likely using the reformulated version. However, if you have older boxes sitting in a bathroom drawer, those could still contain the original PTFE-based material. There’s no simple way to tell from the packaging which version you have, so if this concerns you, replacing older stock with a fresh purchase is a reasonable step.
How Glide Compares for Cleaning
Setting the chemical question aside, Glide-style monofilament floss has real advantages for certain mouths. Its thin, smooth profile makes it easier to slide between teeth that sit very close together. For people with tight dental contacts, where thicker nylon floss shreds or gets stuck, a monofilament floss can be the difference between actually flossing and giving up on it. Dentists have long recommended it for patients who find traditional floss uncomfortable or frustrating, on the principle that the best floss is the one you’ll actually use.
When used properly, both monofilament and multifilament floss are effective at removing plaque and food debris. Neither type has a clear clinical edge in cleaning ability. The choice comes down to comfort, tooth spacing, and personal preference. If you have wider gaps between teeth or any gum recession, a thicker or textured floss may grip the tooth surface more effectively. If your teeth are tightly packed with no gaps, a smooth monofilament floss is often the better fit.
PFAS-Free Alternatives
If you’d rather avoid any possibility of PFAS exposure, or if you simply want to explore other options, several categories of floss are worth considering:
- Waxed nylon floss: The classic option. It’s slightly thicker than monofilament floss but works well for most people. The wax coating helps it glide between teeth without shredding.
- Unwaxed nylon floss: Thinner than waxed versions and can squeeze into tighter spaces, though it’s more prone to fraying.
- Silk floss: A biodegradable option that’s gained popularity among people looking to reduce plastic use. It tends to be coated in natural wax for smoother movement.
- Bamboo fiber floss: Another eco-friendly choice, though availability and quality vary by brand.
When shopping, look for products that specifically state they are PFAS-free or PTFE-free on the label. Some brands that tested positive for fluorine in the original research were not marketed as “Glide” or “smooth” products, so the brand name alone isn’t always a reliable guide. Consumer Reports and environmental advocacy groups maintain updated lists of tested floss products if you want specifics.
The Bottom Line on Safety
The original concern about Glide floss was grounded in real science: PFAS chemicals were present in the product, those chemicals were showing up at higher levels in users’ blood, and PFAS carry well-documented health risks. But Oral-B has since removed PFAS from the formula, which directly addresses the core problem. If you’re buying Glide today, the product is materially different from the one that generated the headlines.
What hasn’t changed is that skipping flossing altogether poses a far clearer risk to your health than any floss material on the market. Gum disease, tooth decay, and the systemic inflammation linked to poor oral health are well-established dangers. Whatever floss you choose, using it daily matters more than the brand on the package.