Oral cancer is diagnosed in many young adults who haven't used tobacco or alcohol for long enough to be part of the normal high-risk group for cancers of the mouth. Doctors at Georgetown University Hospital reported on one possible risk factor at a conference in August 2004, a process that is generally considered to be safe: tooth whitening.

What the researchers wanted to know: Is there any chance of a link between tooth whitening and oral cancer?

What they did: Two oral cancer patients in their 20's at Georgetown said they had used tooth whiteners two or three years before diagnosis, so doctors got to thinking: Maybe tooth whitener isn't as safe as it appears. Hydrogen peroxide can cause cancers in mice. Saliva neutralizes hydrogen peroxide, but it's possible that the chemical could come in contact with small parts of your mouth during whitening, without being washed away. So the researchers contacted people who'd been diagnosed with oral cancer at Georgetown between 1997 and 2003. The 19 former patients answered questions about alcohol, tobacco, and tooth whitening.

What they found: Three of the 19 patients had used tooth whiteners. All three had diseased lymph nodes, compared with just three of the other 16 patients.

What the study means to you: This ab. so. lute. ly. does not prove tooth-whitening causes cancer, so it's a little early to get all whipped into a tizzy about it. But the study does suggest an intriguing topic for research.

Caveats: The study is teensy, it doesn't compare patients who had cancer with controls, and it was presented at a conference, which means it hasn't had to go through peer review.

Find out more: All about oral cancer, from the National Cancer Institute: www.cancer.gov

The study was presented at the 6th International Conference on Head and Neck Cancer in Washington, D.C. As a result, there's no published paper.