Teeth Whitening - Chemical Versus Light-activated Procedures

With all the buzz surrounding teeth whitening these days arming your self with good information gives you the best opportunity to choose the right procedure suited to your lifestyle and budget. This article will help you understand the difference between chemical and light-activated teeth whitening and whether there is clinical evidence proving one procedure out performs the other.

Chemical tooth whitening is simply the application of a hydrogen peroxide-based bleaching agent to the teeth for a specified time, usually three applications of twenty minutes each. The concentration of hydrogen peroxide used is usually stronger than what is used in light-activated procedures. A chemical based bleaching solution will typically consist of thirty eight percent hydrogen peroxide whereas a light-activated procedure may use only a fifteen percent solution of hydrogen peroxide.

The usefulness of the addition of light to activate the bleaching agent has long been a subject of controversy in the cosmetic dental community. Those in favor of light activation procedures argue that the introduction of a very high intensity plasma arc light or argon laser triggers a chemical reaction causing the hydrogen peroxide to break down into its component parts of oxygen radicals and water speeding up and enhancing the whitening process.

However controlled experiments in the laboratory have shown laser-activated hydrogen peroxide did not produce any perceivable color change. Another laboratory study showed the use of intense light elevated the temperature of the bleaching solution resulting in an increase in the temperature inside the tooth root. This could have an effect on post bleaching tooth sensitivity and pulpal health.

One possible reason for the introduction of light-activated devices such as plasma arc, light emitting diodes, argon lasers, met­al halide, and xenon-halogen lights is dental manufacturers want to create a public awareness and demand for light-enhanced tooth whitening procedures. The purchase of a bleaching light can cost a dentist tens of thousands of dollars, a strong motive for dental manufacturers to promote these devices as the future of cosmetic dentistry.

Another reason is light-activated bleaching systems result in increased whitening immediately following bleaching compared with strictly chemical teeth whitening procedures. A randomized, parallel and blinded clinical evaluation study published in a January 2006 dental magazine deduced this was because of tooth dehydration due to the creation of heat from the light source.

However the increased whitening effect produced by light-activated procedures was only temporary as the teeth in all evaluated subjects showed an increase in yellow coloration for two weeks. At two weeks post bleaching yellowing stopped and this clinical study showed no difference in the tooth shade of patients using strictly chemical based or light-activated procedures.

Tooth sensitivity was not a problem for any of the participants of this clinical evaluation and everyone was satisfied with their results. Until more conclusive evidence is found, it appears there is no perceivable difference in the teeth whitening results produced by either chemical or light activated procedures.