Dental Bleaching, also known as teeth whitening, is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. According to the FDA, whitening restores natural tooth colour and bleaching whitens beyond the natural colour. There are many methods available, including brushing, bleaching strips, bleaching pens, bleaching gels, laser bleaching and natural bleaching.
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 structures of enamel and bleaches stain deposits in the dentin. Power bleaching uses light energy to accelerate the process of bleaching in a dental office.
Causes of Tooth Discolouration
As a person ages, the adult teeth often become darker due to changes in the mineral structure of the tooth, as the enamel becomes less porous and phosphate deficient. Teeth can also become stained by bacterial pigments, food-goods, and vegetables rich with carotenoids or xanthonoids. Certain antibacterial medications such as tetracycline can also cause teeth to stain or a reduction in the brilliance of the enamel. Ingesting coloured liquids like coffee, tea and red wine can also discolour teeth.