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Week of 21 November 1997

Vol. I, No. 13

Health Matters

How white is right?

My teeth have been getting yellow over the past few years, and I've considered bleaching them. Will that make them perfectly white again?

The effectiveness of tooth bleaching depends in part on the color of your teeth. While some patients can restore their tooth color to pearly white, others will observe less dramatic improvement. However, according to Dan Nathanson, D.M.D., professor of dentistry and chair of the department of restorative sciences and biomaterials at Boston University's Goldman School of Dental Medicine, most patients who opt to bleach their healthy teeth will notice a difference. "Bleaching cannot change the shades of crowns or other fillings, but it often can counteract the effects of aging on teeth in older people, whose teeth get more yellow with age. It can also be useful for children who have taken tetracycline for a medical condition, since tetracycline can sometimes discolor teeth," he says.

People can bleach their teeth either by visiting a dentist or by using a home bleaching kit available through a dentist. In the former, the dentist first isolates the teeth to be bleached, then applies a gel of concentrated hydrogen peroxide (H2O2) solution for about 20 minutes. Sometimes a dentist may augment the solution by applying heat and light. "The treatment takes from one to three visits to complete, and the applications have to be at least seven to ten days apart," he says. "About one-third of patients will experience a brief sensitivity to heat and cold, although this will diminish." Office treatments can range from about $150 to $250 per session.

Home bleaching, which has become more popular recently, uses a less concentrated gel. Patients come to the office to be fit for a bleaching tray, similar to mouth guards used by athletes. Each night for a period of two to four weeks, they apply a carbamide peroxide gel and sleep with the tray in place. Nathanson warns patients not to put the gel on for longer than their doctors prescribe. "Some people want their teeth to be as white as possible, but if you apply peroxide for too long you can damage your teeth," he says. As with the office treatments, about one-third of patients will experience sensitivity to heat and cold, but because of the milder gel, the sensitivity is less. The home bleaching process can range in price from $250 to $600 and includes the bleaching kit, the tray, and several visits.

Both treatments are usually effective for one to two years and can be supplemented by boosters about every two years. An office booster involves a quick visit to the dentist, while a home bleach booster involves wearing the bleaching tray for a shorter amount of time than during the initial course. Those satisfied with the results can continue with boosters indefinitely.

Some home bleaching kits are available in stores, although Nathanson does not recommend using them. "Often the mouthpiece won't fit correctly, and sometimes the solutions can harm the teeth. When you apply these gels to your teeth, it is essential that you be supervised."

Keep in mind that teeth that have undergone root canal treatment cannot be bleached in the same way as healthy teeth. Nonvital bleaching is effective, however, although it is a more complicated procedure.

Finally, bleach toothpastes are beginning to enter the marketplace. They are safe to use because they contain a low concentration of the bleaching solution, much lower than the concentration used in the home kits. However, their effectiveness has not yet been well documented. If you have any questions about this, consult your dentist.

"Health Matters" is written in cooperation with staff members of Boston Medical Center. For more information on tooth bleaching or other health matters, call 800-682-2862.