First up – how it works: The lights must be used in conjunction with a teeth-whitening substance, such as hydrogen peroxide or other whitening agents. After you or your dentist applies the whitening agent to your teeth, targeting the light on your teeth activates the whitener.
Is using light-activation worth it, though? Researchers found that laser, halogen, and LED light-activation produced increased lightening of tooth shade and maintained the lighter shade longer than non-light-activated teeth whitening in a study published in the Journal of Conservative Dentistry. Laser and halogen lights were most effective.