Teeth whitening is a cosmetic treatment to remove stains and dirt from the teeth in order to recover a whiter and brighter tone of the pieces. This technique does not cause pain to the patient and can be carried out in three different ways. The first is the in-office bleaching, which usually lasts an hour and whose advantage is to get a color change in a short period of time. To do so, the dentist applies protects the gums and teeth peroxide gel of high concentration, and then may use a special laser light that facilitates the penetration of the gel into the enamel. The second treatment is a professional home kit, in which the patient applies a lower concentration of peroxide gel on the teeth, but remains longer in the tooth, can provide better results. The application of the gel takes place in a splint tailored to the teeth by the dentist. Finally, the third system is the home bleaching, in which the patient purchase a simpler kit containing a gel professional kit lower concentration, and that is applied by a single nozzle size. The success of this treatment depends on the time of use.