Many tooth whitening treatments suggest the use of a light source, as it is believed to help improve the overall result.
However, a recent study in the Journal of Photochemical and Photobiological Sciences (Jan 16, 2009) argues that ultraviolet (UV) light not only doesn’t enhance teeth whitening, it can actually be dangerous to patients and dentists who are exposed to it.
UV light is claimed by most manufacturers to improve whitening efficiency. But Ellen Bruzell, Ph.D., of the Nordic Institute of Dental Materials said her team’s research found no evidence to support this claim and that, in fact, UV light-assisted teeth whitening can damage skin and eyes up to four times more than sunbathing.
The study conducted compared teeth whitened with UV light according to the manufacturers recommendations, vs teeth whitened without irradiation. Seven different light whitening systems were evaluated. The whitening effect for both groups was measured immediately after treatment and one week later. The study showed that one week after whitening, there was no significant difference between those teeth whitened with a light source and those whitened without irradiation. Much of the difference seen in office whitening done with a light source vs in office whitening done with a stronger solution is the result of dehydration, and once the teeth re-hydrate, there is little difference.
This study suggests that light-assisted whitening is a waste of time and money. In addition they conclude that “the use of optical radiation in tooth whitening poses a health risk to the client and violates radiation protection regulations”. Therefore they advise against light-assisted tooth whitening.
In-office whitening can still produce faster results than the take-home whitening kits available, but it relies on a stronger solution to speed up the whitening process, not a UV light. Because of the strength of the solution, direct dental supervision is required and therefore the procedure must be completed in a dental office.