Tooth Whitening Procedures Explained

So, you want whiter teeth. You are not alone. Habits such as tobacco use, wine drinking, and a propensity for a daily Starbucks is driving patients to their dentist offices in droves for professional tooth whitening. In this first of a two part series, I will discuss what tooth whitening is, how it works, and common methods of application.

Professional tooth whitening is a procedure that uses a chemical agent to remove intrinsic (inside the tooth) stain from teeth, thereby making them whiter. Many products on the market claim to whiten teeth. Toothpastes, toothbrushes, mouth rinses, gels, pastes, coated "strips," gum... the list goes on and on, but most of these only remove or reduce surface (extrinsic) stains, not the brown, gray, and yellow intrinsic stains that can truly dull your smile. The chemical agent in professional tooth whitening preparations is hydrogen peroxide or carbamide peroxide. It comes in gel form and works by penetrating the enamel layer of teeth and oxidizing discolorations in the dentin layer below the enamel.

Carbamide peroxide is hydrogen peroxide plus urea. Urea is added to stabilize the hydrogen peroxide and to give it a longer shelf life. Carbamide peroxide solutions usually come in 10% - 22% strengths. Because it is more concentrated, hydrogen peroxide solutions are available 3% - 14% strengths. Your dentist can evaluate your teeth to decide what is best for you. The two most popular professional applications are done by custom tray method and in-office, direct-application method.

Most professional whitening is done at home by the custom tray method. The dentist will take impressions of your teeth and fabricate thin plastic trays molded from your impressions. The dentist, hygienist or assistant will match your teeth to a "before" shade, give you instructions on using the product, and send you home. Home treatment usually takes two to six weeks depending on the product. Your dentist should monitor your treatment and make changes if necessary. A major benefit of at-home whitening is that the custom trays should fit your teeth for years to come, so occasional touch-up treatments for maintaining your white smile should be easy and relatively inexpensive.

In-office whitening is becoming more and more popular due to its fast, dramatic results. It is done in the dentist's office, usually in about an hour, though some treatments may require two visits for maximum whitening. For this procedure, a much stronger concentration of hydrogen or carbamide peroxide is used. Care should be taken by the dentist to protect the gums and other soft tissues of the mouth to prevent burns. Sometimes a light is used to illuminate the teeth during the process, supposedly to speed up the process, though studies are showing that it does not produce whiter teeth. In-office whitening is more expensive and may cause increased sensitivity, topics I will discuss later, but for patients who may not follow through with the home treatments, this may be a better option.

Other options for whitening are available, though they are not as popular as custom tray tooth whitening and in-office whitening. These are trayless methods which use peroxide-coated, plastic film that is placed directly on the teeth at home. These may be a good option for those considering tooth whitening, but are not sure if they can tolerate the procedure.

Now you know the basics of how tooth whitening is achieved. In Part 2, I will discuss the limitations and side effects of tooth whitening, maintenance options, the costs associated with tooth whitening, plus some ideas that might get you a discount.