Regardless of how well you care for your teeth, it is inevitable that, over time, some yellowing or discoloration will occur. This gradual change can be caused by aging, substances that stain your teeth (such as coffee and tobacco), excessive fluoride, or the deterioration of a tooth's nerve. A tooth whitening treatment can be performed either as an at-home, dentist-supervised process or in the dentist's chair. While neither of these methods stops future discoloration, these treatments bring about whiter teeth and help create a brighter smile.

At-home Whitening
The most popular method of whitening teeth is the at-home, dentist-supervised option. During your visit to the dentist, he or she takes a mold of your teeth and creates a comfortable, customized mouthtray. The mouthtray holds a mild solution whose main ingredient is carbamide peroxide, a substance that reacts with water to release a non-toxic bleaching element (hydrogen peroxide). The mouthtray is placed inside the mouth, and sits only against the teeth, thereby avoiding contact with the gums. Patients can choose either to wear the mouthtray throughout the night or for stretches that last from two to four hours. When the mouthtray is worn throughout the night, the treatment lasts one to two weeks. Patients with more sensitive teeth may opt for the latter approach, which lasts three to five weeks.