Teeth whitening, also known as dental bleaching, is a very common procedure in dentistry used to restores natural tooth colour. There are many methods available, including take home bleaching kits and also "laser" bleaching (Zoom whitening).
Bleaching methods use carbamate peroxide which reacts with water to form hydrogen peroxide. Carbamate peroxide is about a third of the strength of hydrogen peroxide which means that a 15% solution of carbamate peroxide is the rough equivalent of a 5% solution of hydrogen peroxide. The peroxide oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and bleaches stain deposits in the dentin. Custom dental trays are made to fit the patients mouth, and the patient is able to apply the bleaching material usually twice a day for about two weeks. Light-accelerated bleaching uses light energy to accelerate the process of bleaching in a dental office. Light-accelerated bleaching is commonly called "laser" bleaching which is a common misconception since lasers are an older technology that was used before the current technologies were developed. Different types of light energy can be used in this procedure, with the most common being halogen, LED or plasma arc. Clinical trials have demonstrated that halogen light is the best source for producing optimal treatment results. The ideal source of energy should be high energy to excite the peroxide molecules without overheating the pulp of the tooth. Lights are typically within the blue light spectrum as this has been found to contain the most effective wavelengths for initiating the hydrogen peroxide reaction. A "laser" bleaching treatment typically involves the isolation of soft tissue with a resin-based, light-curable barrier, application of a professional dental-grade hydrogen peroxide whitening gel and exposure to the light source for 6-15 minutes at a time, for a total of usually 30-60 minutes.