Many tooth whitening treatments suggest the use of a light source as it is believed to help improve the oxidising effect of the bleaching compound hydrogen peroxide.
However, a recent study in the journal Photochemical and Photobiological Sciences, argues that using lamps makes no difference to the end result and may be dangerous for the client and the operator.
Researchers form the Nordic Institution of Dental Materials investigated 7 different bleaching systems that were commercially available on the Scandinavian and US markets in 2005.
Using human molars donated after extraction, the team bleached one half of the tooth following the manufacturers’ recommendation and the other was left as a control.
Half of the bleached teeth received both the bleaching gel and the radiation and the other half just the bleaching gel.
The team then went on to investigate the light sources to see whether the treatment time exceeded the recommended exposure times to such radiation.
Light didn’t make teeth whiter
According to the study, there was no statistical difference in the colour change of the teeth with bleaching gel and radiation and those treated simply with the product.
Although the study acknowledges that the exposure to clients and operators of the machinery will vary greatly between clinics and treatments, it concludes that the use of optical radiation in teeth bleaching poses a health risk.
Clients may be exposed to up to 60 minutes of radiation to the teeth and mouth area, and the scientists note that little is known about the effects of visible light and UV radiation on mucous membranes such as the inside of the mouth.
In addition, depending on the placing of the lamps and the protection worn, clients may experience a dangerous level of radiation to the eye, the scientists claim.
These two factors, coupled with the fact that there were no discernable benefits from the radiation, led the researchers to advise against using light-assisted tooth bleaching.
Source: Photochemical and Photobiological SciencesDOI: 10.1039/b813132eIn vitro efficacy and risk for adverse effects of light-assisted tooth bleachingEllen M. Bruzell, Bjørn Johnsen, Tommy Nakken Aalerud, Jon E. Dahl and Terje Christensen