Dental bleaching, also known as tooth whitening, is a common procedure in cosmetic dentistry. 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 breaks down stain deposits in the dentin. Power bleaching uses light to accelerate the process of bleaching in a dental office. Bleaching whitens beyond the natural color.