Q. Do tooth whiteners cause cancer?
A. Right now, there’s no evidence that they do. Despite worrisome headlines, the link hasn’t been scientifically studied. What happened: Georgetown University Hospital researchers found that two oral-cancer patients had used tooth whiteners, so they mentioned the coincidence at a medical conference.
Why the fuss? The active ingredient in most whiteners, carbamide peroxide, can come in contact with the gums. Peroxide can produce free radicals, molecules that may lead to cancer, but there is little evidence of risk, says Dr. Ted Gansler of the American Cancer Society. Worried? Then avoid whiteners. If you keep using them, follow directions, and don’t overdo.