Home tooth-bleaching works, safe over short-term

NEW YORK (Reuters Health) - Tooth-whitening kits for use at home will indeed brighten your smile, according to an analysis by independent researchers of the results of 25 studies of these products.

However, there's no evidence that the kits are safe to use for longer than two weeks, the authors of the review note, and all of the studies they analyzed were conducted by or paid for by the product makers.

"There is an urgent need for independent long-term studies evaluating the effectiveness and harms associated with the home use of bleaching products," Dr. Hana Hasson of the University of Michigan in Arbor and colleagues conclude in their report in The Cochrane Library.

Bleaching products generally contain hydrogen peroxide or carbamide peroxide, and may be dispensed by dentists or sold over the counter. These products first became widely available in the 1990s, but to date there has been no critical evaluation of studies supporting their safety and effectiveness, the authors note.

The researchers sorted through 416 published articles on home tooth-whitening products and identified the 25 highest-quality trials. They then examined the studies in detail, analyzing the quality of the results and the risk that the findings were biased.

Twenty-one of the studies had a high risk of bias, while four had a moderate bias risk, the authors report. All studies that compared the kits to placebo found that they were effective for whitening teeth.

Side effects included mild to moderate tooth sensitivity and gum irritation. While products with a higher concentration of bleaching agent worked faster, they also carried a higher risk of side effects.

The researchers conclude that the products appear to be safe for short-term use, but urge that independent studies be performed to evaluate their long-term safety.

SOURCE: The Cochrane Library, October 18, 2006.