British scientists have released results of a study concluding that UV light-enhanced tooth bleaching is not only ineffective, but dangerous. The study, in the journal Photochemical & Photobiological Sciences, found that exposing one's choppers to the UV lamp exposed sensitive mouth skin and eyes to four times as much skin-damaging UV radiation as the same duration in the midday sun. And who wants to put sunscreen on their gums?

Tooth bleaching has become regular part of many people's cosmetic routine, usually accomplished by application of hydrogen peroxide or a similar bleaching agent. The UV light gimmick is sold with the claim that it enhances the bleaching process, which the study found untrue. It did, however, find that the bleached teeth studied showed more grooving than unbleached teeth, which weakens them and provides more surface area in which bacteria can thrive.

Perhaps the safest course of action is for us to change our perception of healthy teeth; after all, don't those snow-white teeth look a bit unnatural? Human teeth are coated in enamel, mostly made up of the mineral crystalline calcium phosphate. It is translucent, so the yellow cast of the underlying dentin usually shows through, giving a normal, healthy tooth a faint yellow color. Pure white teeth are as unnatural as a nose ring.