The pros and cons of teeth whiteners

Walk down the toothpaste aisle at your typical drugstore and you’ll see a range of products that promise to whiten your teeth. Whitening toothpaste, whitening strips, a whitening gel that you can paint on your teeth with a cotton swab or use in a mouth tray, a two-step “daily cleaning and whitening system,” and more.

“I see a lot more attention on pretty smiles,” says Clifton Carey, a chemist at the University of Colorado’s School of Dental Medicine. Tooth whitening, in particular, is “a big thing these days. A lot of sellers and a lot of customers.”

The products at the drugstore all have essentially the same whitening ingredient — the bleaching agent peroxide. If you go to your dentist for a professional tooth whitening, they’ll use a more concentrated peroxide product.

With the in-office procedure, “you get a lot of whitening very quickly, but it requires expertise,” says Matthew Messina, a practicing dentist at the Ohio State University College of Dentistry and a spokesman for the American Dental Association. With such a high-powered bleaching agent, he says, “the dentist has to protect the gums.”

The over-the-counter products are weaker. That means less active whitening but also less risk to the gums, should the whitening agent come in contact. “All of the products are safe if used as directed,” Messina says. Still, they can increase sensitivity of teeth and they can irritate gum tissue. “Anything that doesn’t feel right, you should see your dentist.”

Tooth whitening is best done in a “healthy mouth condition,” Messina says. “Have a thorough exam, make sure your teeth are clean and that plaque and tartar have been removed.” Also, be aware that tooth whitening doesn’t work on crowns or most fillings.

Professional whitening, which will be immediate and last for years, might cost $500 or more and is not generally covered by dental insurance. Products to use at home usually require multiple applications over a week or two, will have a gradual and lesser whitening effect, and will not last as long. Whitening strips can cost as little as $25.

“The do-it-yourself products can be used as a booster, after a professional treatment, to keep the teeth white,” Carey says. “Dentists often recommend this.”

How do these products work? “It’s a surface-type bleach,” Carey says, working on stains that are bonded to tooth enamel. “Bleach is a chemical that breaks those bonds,” Carey says. The staining compounds might remain, but the bleach turns them clear.

The concentrated product that dentists use also dehydrate the tooth somewhat. “That’s the immediate color change — bleaching plus dehydration,” Carey says. As the surface of the tooth rehydrates over the next few weeks, people may notice their teeth’s whiteness slip back a couple of shades.

If you spend a little time searching the web, you’ll find plenty of ideas about natural methods of tooth whitening.