AThere are many methods to whiten teeth: bleaching strips, bleaching pen, bleaching gel, laser bleaching, and natural bleaching. Traditionally, at-home whitening is done with bleaching gel which is applied to the teeth using thin guard trays. At-home whitening can also be done by applying small strips that go over the front teeth. Oxidizing agents such as hydrogen peroxide or carbamide peroxide are used to lighten the shade of the tooth. The oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and oxidizes interprismatic stain deposits; over a period of time, the dentin layer, lying underneath the enamel, is also bleached. Power bleaching uses light energy to accelerate the process of bleaching in a dental surgery. The effects of bleaching can last for several months, but may vary depending on the lifestyle of the patient. Factors which will decrease whitening include smoking and the ingestion of dark colored liquids like coffee, tea and red wine.
Internal staining of dentine can discolor the teeth from inside out. Internal bleaching can remedy this. If heavy staining or tetracycline damage is present on a patient's teeth, and whitening is ineffective, there are other methods of whitening teeth. Bonding, when a thin coating of composite material is applied to the front of a person's teeth and then cured with a blue light can be performed to mask the staining. A veneer can also mask tooth discoloration.