Teeth Whitening With Light - Where are We Today?

Tooth bleaching light does not make teeth whiter than teeth whitening without light. It is proven that teeth whitening without light bleaches as well as whitening with light.

Several manufacturers now offer systems for teeth whitening at the dentist where the use of light is included. Such systems are also used by hairdressers, skin and beauty salons and others who offer teeth whitening.

Tooth whitening is now a treatment option for patients with discolored teeth. Bleaching can be performed either at home, where the treatment instituted and followed up by a dentist or at a dental clinic, so-called office bleaching. The products used do all have hydrogen peroxide as the active substance, either directly or as a decomposition of carbamide peroxide.

The use of light with the bleach may provide an immediate drying of the teeth if the heat transfer is sufficient. That is probably why the teeth look extra white right after the treatment with some systems.

Bleaching of teeth has become widespread, and it is largely cosmetic, rather than dental causes for the treatment. There is as of today no figures on the extent of such treatment, but some dealers report a doubling in sales of bleaching products in the last couple of years. The marketing is very active and is aimed at both dentists and patients. The treatment often given to young people and is often repeated with less than one to a few years. For several of the office bleaching systems there is recommended or expected use of the lamps that emit ultraviolet (UV) radiation and blue light.

Use of electromagnetic radiation, specifically in the ultraviolet, visible and infrared spectrum of teeth whitening procedure is currently little scientifically based. In a clinical evaluation of a bleaching system with light there was found a better effect in the group that was bleached with light than in the group which was bleached without light, both immediately and after 6 months. This study, however, was financed by the manufacturer of the bleaching system. In another study, it is not found significant difference in the bleaching effect by the use of light.

In an evaluation of the Clinical Research Associates (CRA) involving seven different whitening systems, it was shown that the bleaching light did not give whiter teeth than the use of the same systems without light. CRA also concluded that some systems bleached faster, and some achieved a good efficiency with less hydrogen peroxide. Nor was there any difference in the bleaching result after one year if a light was used or not. A laboratory study of four different bleaching systems showed that the bleaching efficiency (assessed 3 minutes after bleaching) increased by the use of light, but so did the tooth temperature, with the danger of drying and a "false" visual impression of increased whiteness.

One could imagine that lighting liberated or activated substances in the bleaching gel, but this does not seem to be the case. Thus, it is the active ingredient in bleaching material (hydrogen peroxide), which provides the bleaching effect. This is also consistent with previous studies, where one could not prove increased release of bleaching substances by using light.

Conclusion

There are no significant differences between the teeth being bleached with light and accordingly no light when the color will be reviewed after one week. These findings, together with the risk of adverse effects from light exposure means that we discourage the use of light sources in conjunction with tooth bleaching. The use of light in teeth whitening provides no additional effect, but can cause biological side effects, and is therefore not recommended.

As presented in the international journal Photochemical & Photobiological Sciences