RESEARCH

U-M Clinical Associate Professor Evaluates Studies

Dr. Hana Hasson discusses the results of her evaluations of tooth whitening studies with a reporter from Ivanhoe TV at the School of Dentistry. Ivanhoe TV has been providing television stations with news stories about medicine and dentistry since 1982.

You see commercials for them on television and ads in newspapers and magazines.

Tooth whiteners - whitening strips, guards filled with gel placed over the teeth, and paint-on films - are available at almost every drug and food store as well as from many dental offices.

But how effective are they?

Tooth whiteners appear to be effective, short term. But their long-term effectiveness has yet to be determined.

Those are the findings of a review of all published studies through 2006 by Dr. Hana Hasson, a clinical associate professor at the U-M School of Dentistry.

More than 400 studies about the effectiveness of the whiteners have been published in recent years. Hasson reviewed 25 of the higher-quality studies and evaluated their effectiveness after two weeks. Studies encompassed controlled and semi-controlled situations that involved products recommended by dentists and products that could be purchased over the counter. Tooth-whitening toothpastes were not included in the assessment.

Her conclusion of the review is that there is evidence whitening products work. However, there are differences in the efficacy of products, due primarily to the levels of active ingredients, including hydrogen peroxide and carbamide peroxide.

All trials were short term and involved high-risk bias since they were sponsored or conducted by the manufacturers of the products.

Hasson said there is a need for long-term and independent clinical studies that include participants from various groups, as well as a need to better measure common side effects of tooth sensitivity and gingival irritation.

The result of the research appeared last fall in The Cochrane Library, a publication produced by The Cochrane Collaboration, an international organization that evaluates research.