No whitener is permanent: The whiteness you get from a treatment in the dentist's office may be more thorough, but it lasts about as long as the whiteness from an over-the-counter regimen, says Wolff. How fast your teeth become stained and discolored, he says, depends on your diet and medications. If you drink and eat foods that leave stains — from red wine to blueberries — stains will reappear faster and your bright white teeth will fade. If you are careful and limit these foods and liquids, your brighter teeth should stay that way for about six months.
Weigh the differences in procedures: Should you choose a visit to the dentist's office or an over-the-counter whitening product? It depends. "Often, over-the-counter teeth-whitening trays do not fit properly, which may cause the gel to leak," says Flax, of the American Academy of Cosmetic Dentistry. He says that whitening strips can slide, "getting acid on your gums." If you are starting with sensitive teeth, a dentist can offer more comfortable whitening processes. And if you want a quick fix, going to the dentist is a speedier way to whiten teeth.
On the other hand, "at-home whitening trays have worked well for more than 20 years," says Flax.
Wolff points out that while the strips are effective, the trays do work better if applied correctly.
Costs: Laser whitening will run around $1,000; a bleaching application in a dentist's office costs about $500. If the dentist does an initial bleaching and then sends you home with a kit to use, expect to pay around $300.
The costs of over-the-counter whitening kits can vary widely — from $30 to $300. Don't be snookered into the more expensive products, says Wolff. "Consult your dentist first before putting out that kind of money on an over-the-counter product."
Beth Levine is a freelance writer who lives in Stamford, Conn.