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PFAS in Dental Floss: Checking a Viral Post About Glide
A viral post says Oral-B Glide floss had 'forever chemicals' linked to cancer. The 2019 study is real, Oral-B says it dropped PFAS in 2026, and the risk is unclear.
Original commentary from the Cancer Explained editorial team.
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“Independent lab testing found Oral-B Glide had the highest level of PFAS "forever chemicals" of any floss tested.”
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"Independent lab testing found Oral-B Glide had the highest level of PFAS 'forever chemicals' of any floss tested."
That line opens a reel from @purascans that has been shared widely. It goes on to say PFAS are linked to cancer, that Maine banned them in dental floss as of 2026, and that Oral-B says Glide is now made without the coating. Instagram labels the post as AI content.
Most of that checks out. But the testing is from 2019, the cancer link is more complicated than one line can carry, and the product has since changed.
The study behind the claim
In January 2019, researchers at Silent Spring Institute, led by Katie Boronow, published a study in the Journal of Exposure Science & Environmental Epidemiology. They did two things.
First, they tested 18 dental flosses for fluorine, a sign that PFAS may be present. All three Oral-B Glide products they tested were positive, as were two store brands labeled "compare to Oral-B Glide" and one floss described as a single-strand Teflon fiber.
Second, they measured 11 PFAS in the blood of 178 middle-aged women and asked about their habits. Women who flossed with Glide tended to have higher levels of one PFAS, called PFHxS.
The 2019 study reported which flosses contained fluorine. It did not rank them, so the post's "highest level of any floss tested" does not come from that study.
What changed in 2026
On March 31, 2026, Silent Spring reported that Oral-B has eliminated PFAS from its Glide line. Oral-B says the updated Glide uses a "micro-textured fiber" and that none of its flosses are made with PFAS. Silent Spring's report does not include new independent testing of the updated floss.
The post is also right about Maine. The Maine Department of Environmental Protection lists dental floss among the products that cannot contain intentionally added PFAS as of January 1, 2026. Colorado passed a similar ban that took effect the same day.
Do PFAS cause cancer?
PFAS are a large family of thousands of chemicals, and they are not all the same.
In 2023, the International Agency for Research on Cancer (IARC), the World Health Organization's cancer agency, classified two of them:
- PFOA: "carcinogenic to humans" (Group 1)
- PFOS: "possibly carcinogenic to humans" (Group 2B)
The PFAS linked to Glide in the 2019 study, PFHxS, is a different chemical. IARC's 2023 review did not classify it. And none of these studies measured cancer in people who floss. So "PFAS are linked to cancer" is true for some PFAS, but it does not tell you the cancer risk of using a particular floss. Our page on PFAS and cancer explains what is and is not known.
The verdict
Mostly accurate, but dated. The 2019 study found PFAS markers in Glide, and Maine's ban is real. The "highest of any floss" ranking is not in that study, the cancer link applies more clearly to other PFAS, and Oral-B says the product has changed.
What you can do
Keep flossing. Cleaning between your teeth matters for your gums and teeth. If you want to avoid PFAS, Silent Spring suggests skipping flosses that list PTFE (the Teflon material) on the label. For bigger sources of PFAS exposure, such as drinking water, see our PFAS guide.
For help judging posts like this, see how to read a carcinogen classification.
Put the story in context
Prevention, possible warning signs, screening, and diagnosis
The information below is general, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
A news story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.