According to Hana Hasson, DDS, clinical associate professor at the University of Michigan, a new review of existing research suggests that there is a good chance that tooth-whitening products are effective. However, Hasson and colleagues don’t consider the studies in favor of the products to be rock-solid, and they couldn’t find evidence supporting anything other than short-term use.

In the review, Hasson and colleagues assessed the state of research into tooth-whitening products that are designed to be used in the home. Tooth-whitening toothpastes weren’t included in this review.

The review authors looked at 416 studies and chose 25 that they thought were of the highest quality. Then they analyzed the findings of those studies. All 25 studies reviewed were funded or conducted by manufacturers of tooth-whitening products, and all measured their effectiveness after 2 weeks. Only 13 examined effectiveness after 3 weeks, and just six after 1 month or longer.

While the review authors weren’t impressed with the quality of the studies–most were deemed to have a “high” risk of bias—they did find plenty of evidence that the products actually whiten teeth.

“They all work, no matter what type or how they’re applied,” says Hasson. “However, products with lower concentrations of active ingredients such as hydrogen peroxide or carbamide peroxide took longer to work.”

In the studies that analyzed side effects, some patients reported mild-to-moderate tooth sensitivity and irritation to the gums. Whitening strips and products with high concentrations of hydrogen peroxide were most likely to cause tooth sensitivity.

The review authors said that there is a need for independent studies that compare tooth-whitening products to one another. The authors also called for studies into the effects of using the products for more than 6 months.

To date, the ADA has given its seal of acceptance seal to only two tooth-whitening products other than toothpaste: Colgate Platinum Daytime Professional Whitening System and Opalescence Whitening Gel. Both are available directly from dentists.

[Newswise, October 16, 2006]