Teeth whitening or bleaching is probably the most frequent treatment in the area of cosmetic dentistry, which seeks to improve the appearance of teeth, as distinguished from improving their function, or treating tooth diseases.

Teeth may be whitened from one-hour bleaching treatments at the dentist’s office, or home-use whitening kits available at pharmacies. The effect in either case is not permanent and requires occasional touch ups.

Cause of Tooth Discoloration

Although people start life with white teeth, tooth enamel gets worn down after enough years, becoming transparent enough to reveal the yellow-colored underlying material — dentin — to show through. Millions of microscopic cracks in the enamel allow the dentin to show, and also accumulate stains and debris, resulting in a duller appearance. Teeth whitening treatments remove the stains and debris.

• Extrinsic Stains – Extrinsic stains are caused by tobacco, coffee, tea, and other dark-colored drinks. The stains can be partly improved by home brushing, but for people who are middle-aged or older bleaching may be required to get the desired whiteness. The longer stains are not attended to, the more difficult it may be to treat them, as they may penetrate to the dentin.
• Intrinsic Stains – Intrinsic stains are ones that originate in a tooth’s interior, and may be caused by such factors as aging, trauma, and malformation of the tooth. These, too, may be treated with whitening products, but in the worst cases may instead require dental veneers, in which a layer of porcelain is applied over the visible surface of a tooth.
  
  

Professional Dental Whitening

Whitening may be affected with either in-office treatment or take-home kit provided by your dentist. You can expect the effect to last for about a year.

In-Office Whitening

In this procedure, the dentist or technician first applies a painted-on rubber dam to protect your gums. Then a high-concentration peroxide gel is applied to the teeth. It remains on for up to an hour or a few 15 to 20 minute intervals adding up to an hour. The typical cost for this service is $650.

Dentist-Provided Take-Home Whitening Kits

With this method, the patient is provided with a kit that has a lower-concentration peroxide gel. The gel is applied with bleaching trays that resemble mouth guards. The trays may be left on for an hour or even overnight, as specified by the dentist.