A few brands of dental floss do, although I think they all deny having PFAS in them, so I think the best speculative reason I've heard is that it's actually pot

A few brands of dental floss do, although I think they all deny having PFAS in them, so I think the best speculative reason I've heard is that it's actually potentiality lubricants from the machines in manufacture getting onto it - which is just as bad, so those companies saying they don't put PFAS into their floss when there's detectably PFAS on it (and raised levels showing up in people who use it) is not a good defence...