What Is It?

Tooth whitening lightens teeth and helps to remove stains and discoloration. Whitening is among the most popular cosmetic dental procedures because it can greatly improve how your teeth look. Most dentists perform tooth whitening.

Whitening is not a one-time procedure. It will need to be repeated from time to time if you want to maintain the brighter color.

What It's Used For

The outer layer of a tooth is called the enamel. The color of natural teeth is created by the reflection and scattering of light off the enamel, combined with the color of the dentin under it. Your genes affect the thickness and smoothness of the enamel. Thinner enamel allows more of the color of the dentin to show through. Having smoother or rougher enamel also affects the reflection of light and therefore the color.

Every day, a thin coating (pellicle) forms on the enamel and picks up stains. Tooth enamel also contains pores that can hold stains.

The most common reasons for teeth to get yellow or stained are:

• Using tobacco
• Drinking dark-colored liquids such as coffee, cola, tea and red wine
• Not taking good care of your teeth

Aging makes teeth less bright as the enamel gets thinner and the dentin becomes darker.

It is also possible to have stains inside the tooth. These are called intrinsic stains. For example, intrinsic stains can be caused by exposure to too much fluoride as a child while teeth are developing. Other causes include tetracycline antibiotics. They can stain a child's teeth if taken by a mother during the second half of pregnancy or by a child who is 8 years old or younger. Teeth are still developing during these years. Trauma may also darken a tooth.

Tooth whitening is most effective on surface (extrinsic) stains.

Preparation

Other dental problems can affect the success of tooth whitening. For example, cavities need to be treated before teeth are whitened. That's because the whitening solution can pass through decayed areas and reach the inner parts of the tooth. If your gums have receded, the exposed roots of your teeth may appear yellow or discolored. Whitening products will not make them whiter.

If you have tooth decay or receding gums, whitening may make your teeth sensitive. Whitening also does not work on ceramic or porcelain crowns or veneers.

Whitening can be done in the dental office or at home. For in-office whitening, your dentist probably will photograph your teeth first. This step will help him or her to monitor the progress of the treatment. Your dentist also will examine your teeth and ask you questions to find out what caused the staining.

Next, the dentist or a dental hygienist will clean your teeth. This will remove the film of bacteria, food and other substances that build up on your teeth and contribute to the staining. Once this is done, the whitening procedure begins.

For whitening at home, your dentist can make trays to hold the whitening gel that fit your teeth precisely. Home whitening gel usually needs to be applied daily for two to three weeks. Over-the-counter kits also are widely available for home use. They provide trays to hold the gel, or whitening strips that stick to your teeth. Talk to your dentist if you want to use these home products. Be sure to follow directions to avoid overuse and possible damage to your teeth and mouth.

Follow-Up

If you find that your gums are white or sore, follow up with your dentist.

Whitening is not a permanent solution. The stains will come back. If you smoke or consume a lot of staining foods or drinks, you may see the whiteness start to fade in as little as one month. If you avoid these sources of staining, you may not need another whitening treatment for 6 to 12 months.

Re-whitening can be done in the dentist's office or at home. If you have a custom-made mouthpiece and whitening agent at home, you can whiten your teeth as often as you need to. Discuss your whitening schedule with your dentist. You can talk about what whitening products would work best for you.

Risks

Whitening is unlikely to cause serious side effects, although some people's teeth may become more sensitive for a short while. You may get mild gum irritation as well. Women should not have their teeth whitened while pregnant. The effect of the whitening materials on the development of the fetus is not known. Since the procedure is cosmetic, it should be postponed until after delivery.