Dental bleaching, also known as tooth whitening, is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. A child's deciduous teeth are generally whiter than the adult teeth that follow. As a person ages the adult teeth often become darker due to changes in the mineral structure of the tooth, as the enamel becomes less porous. Teeth can also become stained by bacterial pigments, food, wine and tobacco. Certain antibiotic medications (like tetracycline) can also cause teeth stains or a reduction in the brilliance of the enamel.
Generally speaking, whitening tooth pastes mostly use an abrasive to sand down the enamel layer of the tooth to expose the unstained, white layer. The problem with this is that there is a very thin, non-reproducing, finite amount of enamel and by sanding it down, you are bound to run out of enamel one day and expose the yellowish second layer of the tooth called dentin. Dentin can not be whitened. The best way to whiten a smile is in two ways. They both use the porosity aspect of the enamel and deliver a bleaching agent that penetrates the porous enamel and dissolves and removes the stain. This process is separated into two categories. The custom made Take-Home Whitening Trays and the in office, one hour whitening such as ZOOM, Opalescence or any other Laser Tooth Whitening system.
Internal staining of dentin can also discolor the teeth from the 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 the person's teeth can be performed to mask the staining. A veneer can also mask tooth discoloration. The ADA recommends to have one's teeth checked by a dentist before undergoing any whitening method. The dentist should examine the patient thoroughly: take a health and dental history (including allergies and sensitivities), observe hard and soft tissues, placement and conditions of restorations, and sometimes x-rays to determine the nature and depth of possible irregularities.