Teeth Whiteners Work, At Least Briefly

Thinking of sprucing up your smile with at-home tooth-whitening products? Your pearly whites may indeed get pearlier with those products, at least in the short run.

That news appears in The Cochrane Library's online edition.

Hana Hasson, DDS, and colleagues reviewed 25 studies on at-home tooth-whitening products, including products sold in stores and in dentists' offices.

Hasson is a clinical associate professor at the University of Michigan School of Dentistry.

In the reviewed studies, patients used various tooth-whitening gels and strips. For comparison, some got placebos, which contain no active ingredients.

The review shows that the tooth-whitening products did what they promised to do — make teeth whiter. As expected, the placebo was a dental dud.

Long-Term Results?

Most of the studies tracked patients for up to two or three weeks after treatment. So the reviewers don't weigh in on the products' long-term results.

The most common side effects were mild to moderate tooth sensitivity and gum irritation, especially in products with high levels of hydrogen peroxide.

Those side effects might fade away after people stop using the products, the reviewers note.

Looking for a list of the top products? Sorry, the reviewers didn't go there. Most of the studies weren't head-to-head contests.

But they do note that whitening strips containing 5.5 to 6.5 percent hydrogen peroxide were apparently more effective than gel containing 10 percent carbamide peroxide in trays.

Higher concentrations of chemical whiteners were more effective than those with lower concentrations, the review also shows.

Review's Limits

The review only included products containing the chemical whiteners hydrogen peroxide and carbamide peroxide. Abrasive products weren't included.

The review was complex to organize because the products and studies varied so much — and all of the studies may have been biased, note Hassan and colleagues.

"Given the lack of information on long-term benefits and harms, there may be a huge void between the state of knowledge based on the trials sponsored by the manufacturers and the experiences of millions of users of tooth whitening products," write the reviewers.

Their bottom line: "over-the-counter or dentist-dispensed tooth-whitening products can be recommended to the public but with strong cautions."

SOURCES: Hasson, H. The Cochrane Library, Oct. 18, 2006; online edition. Health Behavior News Service.