It is a cosmetic dentistry application which is made to patients who are satisfied with the shape of their teeth and want to have a whiter and a brighter smile . As it can be done in a clinical environment at a physician control within 1 hour , it can also be applied at home by using a special gel prepared by the dentist , its application is already explained by the dentist . In some cases both methods can be applied in a combined way . However, the whitening proces is not a permenant process , and it is important to consume fewer amounts of coloring foods and drinks such as tea , coffee, cigarettes , after the bleaching process is done . The general oral hygiene and the nutritional habits are determinig in the reoccuring of the coloring . According to the amount of the coloring , the teeth whitening can be repeated once a year for reinforcement purposes.