©2007 Publications International, Ltd. Coffee, tea, and cola are notorious for leaving stains on your pearly whites.

Tobacco -- whether it's smoked or chewed -- is one of the worst offenders. Coffee, tea, and colas are culprits as well. Other possible causes include fruit juices (especially grape), red wine, fruits such as blueberries, soy sauce, and curry. Think of it this way: If a food or beverage can leave permanent stains on clothes or carpets, it can probably taint your teeth.

Aging also contributes to the yellowing of teeth. The enamel, which is the hard outer coating of your teeth, wears thin, allowing the underlying layer of yellowish dentin to show through.

And some stains are what's called intrinsic. That is, they actually occur on the inside of the tooth. For example, children who take the antibiotic tetracycline (or whose mothers took it during pregnancy) often have such stains. Silver-colored fillings can sometimes leach out and stain the surrounding tooth.

Some folks simply go ahead and take matters into their own hands, risking damage to their teeth and gums in the process. Before you can safely take action, however, you have to understand what kind of stains are dulling your teeth. And you need to be realistic, too, in what you seek: Even the healthiest, most perfectly maintained teeth are not pure white.

Only your dentist can correct intrinsic stains, through the use of such cosmetic procedures as composite resin bonding and porcelain laminate veneers (which essentially cover the offending colored area with opaque material). Stains from food and drink can often be removed with a professional dental cleaning. Another option is in-office bleaching, such as "Zoom".