Using a laser with a whitening gel, this is an in-office bleaching system. The translucent bleaching gel is applied to the teeth and a laser light is used to activate the crystals to absorb the energy from the light and penetrate the teeth enamel to increase the lightening effect on the teeth. The length of time in the cosmetic dentist's chair depends on the degree of discoloration you have.
Advantage: One visit is usually all it takes for a bright smile.
Disadvantage: The sudden change of color is likely to be noticed by those around you immediately. This is the more expensive of the procedures available, but also the quickest.