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PFAS in dental floss: Bad for our health?

Feb. 18, 2022
An article about coated floss prompted Kirsten Brancheau, BA, RDH, to take a deeper dive into whether polyfluoroalkyl substances—PFAS—on floss is truly a concern. Here's what she learned.

Recently, Dr. Mehmet Oz, a cardiothoracic surgeon, author, controversial television personality, and 2022 US Senate candidate, wrote an article for his daily newspaper column on a link between gum disease and mental illness. One line in particular caught my attention: “Don’t use coated floss—it may have PFAs on it, those carcinogenic chemicals that have been linked to kidney and testicular cancer, decreased semen quality, and ulcerative colitis in adults and thyroid disease and lowered sex and growth hormones in children.”

I am aware of Dr. Oz’s reputation for promoting pseudoscience.1-3 So when I read that sentence in his column, I shook my head and figured it was just another one of his unfounded claims. But I am also aware that he has a wide audience, including many of our patients. I expected some of them would ask me about this claim, and I had better have some hard evidence to refute it. I did a quick Google search of “coated floss and PFAS” and was shocked at the number of sites that popped up with this information. Why had I, a longtime dental hygienist, never heard of this before? I asked my colleagues if they had heard of this, and they had no knowledge of it either.

Also by Kirsten Brancheau:

Melanoma: Daniel's story

These old hands

I knew I had to dig deeper to find the truth because I love my coated floss. That uncoated stuff is just too frustrating to use on tight teeth, and I recommend coated floss all the time—the slipperier the coating, the better. Have I been recommending a carcinogen all this time? The thought shocked me.

What I discovered was that there is one peer-reviewed, scholarly article on the subject, and most of the other sites that mention PFAS in floss either don’t document their sources or refer to the one article I found. According to this article, using a PFA-coated floss was associated with higher serum concentrations of PFAS.4

What are PFAS?

According to the United States Environmental Protection Agency (EPA), PFAS, or polyfluoroalkyl substances, are:

  • Widely used, long-lasting chemicals, components of which break down very slowly over time.
  • Because of their widespread use and their persistence in the environment, many PFAS are found in the blood of people and animals all over the world and are present at low levels in a variety of food products and in the environment.
  • PFAS are found in water, air, fish, and soil at locations across the nation and the globe.
  • Scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals.
  • There are thousands of PFA chemicals, and they are found in many different consumer, commercial, and industrial products. This makes it challenging to study and assess the potential human health and environmental risks.5

None of what I read on the EPA’s website was very reassuring to me. It seems that PFAS are everywhere. So will the amount in floss make a difference in the overall scheme of things? As far as I can tell, right now the answer is that we just don’t know.

Not enough evidence to say for sure

I also contacted the manufacturer of a popular floss for tight teeth and was told that, yes, the floss does contain PFAS. They added, “Please be assured that our products undergo thorough testing and are safe and effective for their intended use. If you have any further questions or concerns, do let us know and we will do our best to assist.” Naturally, I did have further questions and contacted them again. After a couple of weeks I received a response from the floss manufacturer. They once again assured me of their floss’s safety and sent a link to the response that the American Dental Association (ADA) made to the peer-reviewed article mentioned above.6

The ADA’s response basically stated that the one study on this topic was not enough, nor was there a large enough sample size in the study to warrant concern over the safety of FDAs in certain flosses. It was also critical of the methodology used in the study.

The ADA’s response does not actually state that coated flosses are safe; it merely states that there is not enough evidence to conclusively say they are not safe. Given what we do know about PFAS, it seems to me that there is an urgent need for more studies to be done on coated floss to be able to conclusively say that it is either safe or not safe. But until that time, it is up to each dental hygienist to do their own research and make their own decisions on whether or not they feel comfortable using and recommending certain coated flosses.

Please keep in mind that not all coated flosses contain PFAS. Some waxed flosses are PFA free, but hygienists should check with manufacturers to ascertain whether the floss they use or recommend contains PFAS. Unfortunately, my favorite floss—the one I recommend all the time and use myself—contains PFAS. I am now in the process of trying out different flosses on myself to find one that works well with tight teeth.

I would encourage hygienists to not only check whether their floss recommendations contain PFAS, but to also write to manufacturers of flosses with PFAS and request proof of their safety. If they cannot provide it, perhaps it’s time to abandon those nice slippery flosses and begin using and recommending different flosses or alternatives to floss. Better yet, perhaps if the manufacturers hear from enough of us, they will work to find alternative coatings that don’t shred easily and are safe and PFA free.


  1. Gabriel T. ‘Magic’ weight-loss pills and Covid cures: Dr. Oz under the microscope. The New York Times. December 26, 2021.
  1. Gantz S. Mehmet Oz has peddled ‘fat burners’ and other pseudoscience. Now he’s running for Senate in Pa.The Philadelphia Inquirer. December 2, 2021.
  1. Panetta G. Dr. Oz is running for US Senate in Pennsylvania. Here are 8 times he’s made false or baseless medical claims. Business Insider. November 30, 2021.
  1. Boronow KE, Brody JG, Schaider LA, et al. Serum concentrations of PFASs and exposure-related behaviors in African-American and non-Hispanic white women. J Expo Sci Environ Epidemiol. 2019;29(2):206-217. https://pubmed.ncbi.nlm.nih.gov/30622332/
  1. United States Environmental Protection Agency. PFAS explained. https://www.epa.gov/pfas/pfas-explained
  1. American Dental Association. ADA Statement on Study Involving Dental Floss. Oral Health Group. January 21, 2019. https://www.oralhealthgroup.com/news/ada-statement-on-study-involving-dental-floss-1003939091/#:~:text=One%20of%20many%20shortcomings%20of%20this%20study%2C%20according,were%20found%20to%20have%20elevated%20levels%20of%20PFHxS