Whiter teeth, by popular demand

In the past, perfectly white smiles were found exclusively in magazines and achieved only by retouching photos. Today, they seem to be everywhere and are frequently because the teeth themselves have been retouched -- with whitening agents.

Americans spend more than $600 million a year on teeth-whitening products, according to the Academy of General Dentistry, with sales growing 15% to 20% a year.

Patients question their dentists about tooth whitening and bleaching more frequently than any other topic, the American Dental Assn. has found. In 2003, almost 20% of patients asked about whitening procedures; that’s up from 12% in 2001.

Available whiteners range from prescription products costing several hundred dollars to over-the-counter products available for just a few dollars. Effectiveness varies too.

Some people are born with naturally whiter teeth than others, but everyone’s teeth tend to gradually discolor. Coffee, tea and tobacco products are among the biggest offenders, but any colored food can potentially cause staining.

“If you wouldn’t like it to fall on your clothes, then watch out for your teeth,” says Dr. Matthew Messina, a general dentist in Cleveland and consumer advisor for the American Dental Assn.

Most staining involves only the outer surface of the tooth, but deeper discoloration can occur. This type of staining usually develops while the permanent teeth are forming. Exposure to excessive amounts of fluoride and the use of certain medications are among the most common causes.

Although the term “bleaching” is frequently used, Messina says it’s misleading. “Whitening agents don’t alter the tooth enamel chemically,” he explains. “They use a bubbling action that lifts the stain out.”

Because they can potentially damage the gums and soft tissue, the strongest whitening products are available only through a dentist. The most concentrated contain 35% hydrogen peroxide and must be used under the supervision of a dentist.

Dentists can also prescribe similar but less-concentrated whitening agents for use at home. These whiteners are applied using customized mouth trays that have been molded to fit an individual’s upper and lower teeth. Despite their lower potency, home-use products may work as well as the professionally applied treatments.

Dentist-dispensed whiteners don’t come cheaply. A single in-office procedure can cost more than $500; the customized mouth trays required for use at home run $300 or more.

For a less expensive solution, many people are turning to over-the-counter products. Tray-based systems are among the most popular, but adhesive strips, gels and paint-on liquids are also available. Most of these products contain the same active ingredient as products dispensed by the dentist, although in much lower concentrations Some over-the-counter products, however, contain whiteners that are just as potent as home-use products from dentists.

Unfortunately, consumers can’t easily determine which products will work well and which won’t. You won’t find the American Dental Assn.’s Seal of Acceptance on any over-the-counter products. The organization says a dental examination is necessary to identify the underlying cause of the tooth discoloration and determine whether whitening is appropriate.

“There are a number of reasons that teeth are not white,” Messina says. “Not all problems can be solved with whitening products.”

If you decide to try an over-the-counter whitener, select one with a relatively high peroxide concentration. Most contain either hydrogen peroxide or carbamide peroxide. (A product with 10% carbamide peroxide is equivalent to one with approximately 3% hydrogen peroxide.) Choosing a product that’s easy to use is equally important. A whitener that’s too troublesome to apply won’t get used.

If it’s eliminating stains you’re after, you probably won’t be disappointed by tooth-whiteners. But they aren’t the answer for everyone. Even the most expensive procedures won’t eliminate deep stains caused by too much fluoride or lighten a tooth darkened from decay.

Also, keep in mind there’s only so much that whitening your teeth will do for you. In fact, some evidence suggests that “brightening your smile” doesn’t necessarily improve the way you look. Researchers demonstrated this by manipulating the tooth color of men and women in pictures, and then asking people to rate their attractiveness. It turns out that ratings were not influenced by tooth color.

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Dr. Valerie Ulene is a board-certified specialist in preventive medicine practicing in Los Angeles. She can be reached at themd@att.net. The M.D. appears the first Monday of the month.