PTFE-coated dental floss is the most direct PFAS exposure path documented in personal care products. The 2019 Silent Spring Institute study (Boronow et al. Journal of Exposure Science and Environmental Epidemiology) found women who flossed with Oral-B Glide, then made with PTFE, had measurably elevated PFHxS in blood serum. Silk floss, biodegradable corn-PLA floss, and nylon floss with natural wax are verified PFAS-free alternatives.
Research published in 2019 by the Silent Spring Institute turned up something unusual: women who flossed with Oral-B Glide had roughly 25% higher levels of PFHxS – a type of PFAS – in their blood compared to women who didn't. The culprit? Polytetrafluoroethylene (PTFE), the same slippery fluoropolymer used in nonstick pans, which was used to make floss marketed as "glide" or "easy-slide."
Oral-B Glide, a floss originally developed by W. L. Gore & Associates (the maker of Gore-Tex) and bought by Procter & Gamble in 2003, was specifically named. This makes dental floss one of the only consumer products with direct human serum evidence linking routine use to measurable PFAS exposure.
The Silent Spring Institute study (Boronow K.E. et al. 2019) surveyed 178 middle-aged women in California, measured 11 different PFAS compounds in their blood serum, and asked about everyday behaviors thought to raise PFAS exposure. Flossing with Oral-B Glide was examined alongside takeout food packaging, nonstick cookware, microwave popcorn, stain-resistant furniture, and living in a city with PFAS-contaminated water (Boronow et al., PMC6380931).
Women who reported ever flossing with Oral-B Glide had 24.9% higher PFHxS (perfluorohexanesulfonic acid) levels. The EPA set a 10 parts per trillion drinking water limit for PFHxS in April 2024, and in May 2026 proposed rescinding that PFHxS limit while keeping the PFOA and PFOS limits (EPA). The floss association held in a model that adjusted for the other exposure sources the researchers studied.
What made this finding significant: PFHxS has a half-life of 7 to 8 years in human blood, according to the Agency for Toxic Substances and Disease Registry (ATSDR). Daily flossing for years compounds the exposure. The researchers recorded Glide use only as ever versus never, so the data cannot show whether heavier users had higher serum concentrations.
PTFE has one of the lowest coefficients of friction of any solid material. A PTFE strand slips between tight tooth contacts without shredding. Gore created Glide from the same expanded-PTFE fiber technology behind Gore-Tex, and Procter & Gamble bought the brand in 2003 (Silent Spring Institute FAQ). Competitors followed with "compare to Glide" store brands.
From a manufacturing perspective, PTFE solved a real problem. Traditional waxed nylon floss tends to catch or fray between tightly spaced teeth. PTFE-coated floss doesn't. The trade-off: you're rubbing a fluoropolymer against your gums twice a day.
Flosses that tested positive for fluorine (a PTFE marker) in the 2019 Silent Spring testing of 18 products:
Brands that have publicly reformulated:
Brands that are PFAS-free by design:
The packaging often doesn't change between PTFE and PTFE-free formulations. Check the ingredients panel. If you see "polytetrafluoroethylene" or "fluoropolymer," it contains PTFE. If the label says "polyester" or "nylon" alone, you're clear. Some brands now print "PTFE-free" on the package. That label is the manufacturer's own claim rather than an independent certification; the FDA regulates dental floss as a Class I medical device (21 CFR 872.6390), not as a cosmetic.
Even brands that reformulated didn't recall existing inventory. PTFE floss made before a reformulation can still sit on store shelves and in home medicine cabinets, and the old and new versions can share the same brand name and similar packaging.
This is supply chain inertia, and it means the package in hand matters more than the brand name. California's Toxic-Free Cosmetics Act (AB 2771) has banned intentionally added PFAS in cosmetics sold in the state since January 1, 2025, while the separate AB 1817 covers textiles. Because federal law treats floss as a medical device, it is not clear that the cosmetics ban reaches floss at all.
In August 2022, a proposed class action (Dalewitz v. Procter & Gamble) was filed in federal court in New York alleging Oral-B Glide was marketed as "Pro-Health" despite likely containing PFAS. A judge in the Southern District of New York dismissed it in September 2023, finding the plaintiff had not plausibly alleged that the product he bought contained PFAS (Dr. Bicuspid).
California's AB 2771 is not a floss law. It covers cosmetics sold in the state, including makeup, shampoo, lotion, and anything else applied to the human body for cleansing or appearance. PFAS are commonly used in cosmetics for water resistance and texture. The dental floss issue is a small piece of a much larger reformulation wave.
The EPA's April 2024 final rule on PFAS in drinking water set Maximum Contaminant Levels (MCLs) for six PFAS compounds, including PFHxS at 10 parts per trillion. That regulatory attention increases scrutiny on all exposure pathways.
The amount of PFAS absorbed from floss is small compared to contaminated drinking water or occupational exposure. But PFHxS accumulates. With a 7-8 year half-life in blood, daily flossing for a decade means you never fully clear what you absorbed last year.
The Silent Spring researchers didn't quantify total body burden; they measured serum concentration. A 25% elevation in PFHxS blood levels is meaningful because it links a specific, everyday product to a measurable difference in body levels, although the confidence interval was wide (0.2% to 55.7%).
Combined with other PFAS sources – drinking water contamination, food packaging, stain-resistant fabrics – small exposures compound. There's no safe threshold for PFAS exposure that the scientific community agrees on. The EPA based its 10 ppt PFHxS figure on noncancer effects such as thyroid and developmental harm, and in May 2026 proposed withdrawing that limit entirely.
Silk floss – natural fiber, biodegradable, very thin. Breaks more easily between tight contacts, which some dentists argue protects gums from aggressive flossing. Best for standard tooth spacing. Radius Pure Silk and Dental Lace silk are the main brands. Dr. Tung's Smart Floss is often mistaken for silk but is an expanding polyester with natural waxes that the company says is PTFE-free (Dr. Tung's).
Corn-PLA floss – polylactic acid derived from corn starch, compostable in facilities that accept bioplastics. Dental Lace sells a PLA vegan floss alongside its silk. Best for people who want plant-based material. For a stronger synthetic, Cocofloss is woven from mostly recycled polyester with coconut oil and wax, and the company says it is made without PTFE (Cocolab); it is not biodegradable.
Nylon with natural wax – traditional floss without PTFE coating. Smooth enough for most people, slightly less glide than PTFE but most users adapt within a week. Tom's of Maine and Desert Essence make solid versions. Best for tight contacts where silk breaks but you want to avoid fluoropolymers.
Water flossers – entirely different category. Great supplement to traditional floss but don't fully replace it. Water flossers flush debris but don't replicate the scraping mechanical action that removes plaque from the contact surface between teeth.
If you have tight contacts where floss catches or shreds, try a woven polyester floss such as Cocofloss first. It's strong enough to slip through without breaking, though it is not biodegradable. If that still shreds, Oral-B's reformulated micro-textured Glide is an option; Oral-B says it is no longer made with PTFE.
If you have normal spacing, silk floss (Radius or Dental Lace) is the lowest-impact choice. Natural fiber, biodegradable, no synthetic coating. It breaks more easily than nylon or PLA, but that's by design – silk snaps before you damage your gums.
If you have heavy plaque buildup, waxed nylon (Tom's of Maine) works well. The natural wax (usually beeswax or candelilla) helps the floss grip plaque without adding fluoropolymers.
PFAS in dental floss is one exposure path. Drinking water is usually the bigger one. If you're concerned enough to switch floss brands, check your tap water for PFAS contamination. We pull EPA UCMR5 data for every tested system in the US. Enter your ZIP code and see what's in your water.
For areas with detected PFAS, certain water filters remove over 99% of these compounds. Reverse osmosis and activated carbon filters rated for PFAS removal are the most effective home treatment options.
Is Oral-B Glide PFAS-free now? Oral-B says its reformulated Glide uses a new micro-textured fiber that is no longer made with PTFE, and that none of its floss products are formulated with PTFE or any PFAS. Older Glide made with PTFE may still be in stores or at home, and independent testing of the new fiber has not been widely published. If the ingredients panel lists "polytetrafluoroethylene" or "fluoropolymer," it contains PFAS. Old inventory of the PTFE formula may still be on shelves.
Does dental floss actually absorb PFAS into the body? The evidence points that way. In the 2019 Silent Spring Institute research, women who had ever flossed with Oral-B Glide (then made with PTFE) had about 25% higher serum PFHxS. The association held after adjusting for other exposure sources such as takeout food packaging and contaminated drinking water. PFHxS has a 7-8 year half-life in human blood, so daily flossing compounds exposure over time.
Is silk dental floss safe? Yes. Silk floss is a natural fiber with no fluoropolymer coating, making it completely PFAS-free. It's also biodegradable. The main downside: silk breaks more easily between tight tooth contacts than nylon or PLA floss. Most dentists consider this a feature, not a flaw, since it prevents aggressive flossing that can damage gums.
How can I tell if my floss has PTFE? Check the ingredients panel on the package. PTFE may be listed as "polytetrafluoroethylene" or "fluoropolymer." If the marketing emphasizes "glide" or "slide" but doesn't list ingredients, assume it contains PTFE. Brands that reformulated to PTFE-free usually print that claim on the package. Floss labeled only "nylon" or "polyester" without additional coatings is PTFE-free.
Is a water flosser a substitute for regular floss? Water flossers are a supplement, not a substitute. They flush debris and bacteria from between teeth and below the gumline, but they don't replicate the scraping mechanical action that removes plaque from the contact surface where two teeth touch. Most dentists recommend using both – water flosser for irrigation, string floss for plaque removal.