Dental bleaching, also known as tooth whitening and swabbing, is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. According to the FDA, whitening restores natural tooth color and bleaching whitens beyond the natural color.
Bleaching methods use carbamide peroxide which reacts with water to form hydrogen peroxide. Carbamide peroxide has about a third of the strength of hydrogen peroxide. This means that a 15% solution of carbamide 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. Power bleaching uses light energy to accelerate the process of bleaching in a dental office.
The bleaching is not a modern invention. Ancient Romans, for example, used urine and goat milk to make and keep their teeth whiter.