
From MSN Health & Fitness:
Nine Cosmetic Treatments to Rethink // Close-up of woman's smile (© Mario Castello/Fancy/Photolibrary)
Why get it: Who doesn't want a mouth full of gleaming, pearly whites? Most whitening methods rely on hydrogen peroxide solutions, but some companies claim the hydrogen peroxide works better and faster when combined with UV lamps.
The problem: New research shows UV lamps don't boost the bleaching process, and even worse, can be dangerous. In February 2009, research published in the online version of the Journal of Prosthodontics showed no difference between teeth whitened with a combination of hydrogen peroxide and light or heat lamps, and those whitened with the solution alone. A January 2009 study in the British journal Photochemical & Photobiological Sciences went further. Not only does light-activation not work, the article reported, but it also exposes users to startlingly high levels of cancer-causing UV radiation. One lamp the team tested gave a dose four times as high as what you'd get from sunbathing for a full afternoon in midsummer.











