Tooth Whitening

Tooth whitening or tooth bleaching is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. Many people consider white teeth to be an attractive feature of a smile. A child’s deciduous teeth are generally whiter than the adult teeth that follow. As a person ages the adult teeth often become darker. This darkening is due to changes in the mineral structure of the tooth, as the enamel becomes less porous. Teeth can also become stained by bacterial pigments, foodstuffs and tobacco.

As white teeth are subconsciously associated with youth, they have become desirable. This has been made more apparent with the spread of American culture worldwide, where an especially white smile is coined a “Hollywood smile”. Tooth whitening procedure uses oxidising agents such as hydrogen peroxide or carbamide peroxide to lighten the shade of the tooth. The oxidising agent penetrates the porosities in the rod-like crystal structure of enamel and oxidises interprismatic stain deposits; over a period of time, the dentine layer, lying underneath the enamel, is also bleached.

Two main methods of Tooth whitening. The first involves applying a high concentration of oxidising agent for a short period of time, which is the so-called office bleach. This produces quick results but risks chemical burns to the soft tissues. Therefore, most in-office bleaching procedures use a light-cured protective layer that is carefully painted on the gums and papilla (the tips of the gums between the teeth). The bleaching agent is either carbamide peroxide, which breaks down in the mouth to form hydrogen peroxide, or hydrogen peroxide itself. The tooth whitening gel typically contains up to 35% hydrogen peroxide equivalent.