After years of grinding, chomping, and chewing, your once-pearly whites may have seen better days. The gloss of lustrous white enamel has faded, exposing the natural yellow layer beneath. Add to that a lifetime's worth of pigments from coffee, tea, red wine, and soda that have gotten lodged in tiny cracks in your teeth. The result: that unattractive yellowish-brown tint that's made tooth whitening one of the most popular cosmetic dental procedures in the United States. Nearly all cosmetic dentists offer whitening treatments and the number of procedures they perform has jumped about 50 percent each year since 2005, according to the American Academy of Cosmetic Dentistry. More people are also turning to cosmetic enhancements beyond whitening, such as bonding and veneers, which can improve both the function and appearance of crooked, chipped, or worn-down teeth.
Whether applied at home or in a professional's office, reputable whitening products use peroxides, chemicals that release oxygen bubbles to lift out staining pigments and debris. Where whiteners differ is in their peroxide concentrations, the time they take to work, and, of course, cost.
Whitening toothpastes. Supermarkets and pharmacies offer a dizzying array of whitening pastes for less than $10 a tube. Crest alone boasts seven varieties of toothpaste whiteners. Colgate has eight. And that's not even counting the number of different flavors (Caribbean cool, anyone?), gels, baking sodas, and 2-in-1 paste/mouthwashes that promise to brighten your smile. But do they really work? "It depends on the active ingredient," says Laura Kelly, president of the American Academy of Cosmetic Dentistry. Only some brands contain a peroxide, and those that do have very low concentrations—usually 1 to 2 percent. That's enough to remove surface stains and give teeth a good outer cleaning but not enough to make tooth shades whiter. "They're more effective at maintaining your shine after you've undergone stronger in-office or at-home whitening treatments," says Kenton Ross, a spokesperson for the Academy of General Dentistry.
Over-the-counter (OTC) whitening products. The best-known OTC whiteners are strips—thin, cellophane-like tape that adheres directly to the teeth—and gel-filled trays, both falling in the $15-to-$50 range. The bleaching agent in these products can cause irritation or blotching if it comes in contact with the lips or gums, says Ross. To minimize that problem, manufacturers keep peroxide concentrations low, which means you should expect relatively slow, modest results. "The OTC products are ideal for someone going to prom in a week or needing a little touch up here and there," says Messina.
In-office whitening. You'll fetch the most dramatic improvement in the shortest time with bleaching procedures done at a dentist's office. But convenience and results come at a price—often between $500 and $1,000 and even more in major metropolitan areas. Some products, including Zoom and BriteSmile, make use of a high-intensity blue light or laser that purportedly activates the highly concentrated hydrogen peroxide solution and speeds up the process, but it's debatable whether such flashy extras make a difference. In studies, researchers such as Bruce Matis, the director of clinical research at Indiana University School of Dentistry, have found that they don't.
With minimal home follow-up care, in-office bleaching can last for up to five years. However, teeth are vulnerable to restaining shortly after the procedure, so Messina recommends a "white diet" for the first few days: fish, chicken, rice, and water.