A big, bright smile isn't just your best accessory, it also happens to be a key indicator of your overall well-being so it's crucial to schedule a professional cleaning at least twice a year to help buff away tartar, bacterial deposits and external stains, and to check for cavities. During your visit, your dentist can also scope out early warning signs of sickness elsewhere in the body since poor oral hygiene has been linked to heart disease and diabetes.

Not all discolorations can be bleached, so it's best to check in with your dentist to set expectations. For instance, according to the ADA, grayish gnashers, bonded teeth and tooth-colored fillings won't be whitened by a bleaching agent, whereas yellow and brown stains will lighten right up. If your smile is bleachable, ask your doc about an in-office treatment like Luma-light or Zoom, which activates a high concentration of hydrogen peroxide with light wavelengths, taking teeth up to 10 shades lighter.

When it comes to what you can do at home to whiten your teeth, most products rely on contact time to spruce up your smile -- think Crest Whitestrips -- but there's a new generation of gadgets like the Glo Brilliant Personal Whitening Device, $275, which recreates the one-two punch of light plus bleach in the comfort of your own bathroom.

Keep your whitened-teeth longer by avoiding a few common causes of discoloration. Steer clear of blue- or green-tinted mouthwashes, which, according to Emanuel Layliev, D.D.S., director of the New York Center for Cosmetic Dentistry, contain dyes that can lead to staining, especially if the rinse is loaded with alcohol. He says, "The alcohol dries the surface of teeth and restorations thus making the teeth more prone to darkening." He also advises patients to sip coffee, red wine and dark sodas through a straw, since these daily treats can contribute to yellowing. Not sure what will compromise your bright white smile? Layliev says, "A good rule of thumb is, anything that will stain a white shirt will stain your teeth."

While brushing and flossing is "the very best way to clean teeth," according to Layliev, certain foods can help naturally scrub your smile if you're caught unprepared. When you can't brush, nosh on fibrous fruits and veggies like spinach, lettuce, broccoli and apples -- their crunchy textures help eliminate build-up. For fresher breath, chew on all-natural bacteria-busters like parsley, cilantro, and mint. Cucumbers also contain "odor-fighting phytochemicals," Layliev says.

If you've been lax on flossing, your body may be trying to send you a message. Jonathan B. Levine, a doctor of dental medicine in New York City, says, "The main reason your gums bleed is because plaque has been allowed to form along the gum line." Since the health of the mouth affects your general health, Levine says it's important to nip gum disease in the bud by adhering to a daily flossing and a twice-daily brushing routine. If you're not a fan of traditional ribbon floss, clean between teeth with an interdental floss-up or flossette, which is much easier to maneuver.

Somewhere along the way it was drilled into us that we have to brush after imbibing, and for the most part that's true. But according to research, there's a glaring exception to that rule-of-tooth. If you're sipping on drinks containing citric or phosphoric acid -- i.e. fruit juices and sodas -- wait a full hour before brushing, says Kenton A. Ross of the Academy of General Dentistry. "The acid in the drink weakens the enamel and brushing can then remove microscopic amounts of that important enamel layer." Give your mouth a swish with cool water to dilute the acid then brush up later.

If your dentist has determined that a cavity or cracked tooth isn't the cause of sensitivity, worn enamel or an exposed root could be the problem. Too-rough brushing is one of the possible causes of worn-down enamel and receding gums, so ban hard-bristle brushes. To treat sensitivity, try swabbing on a desensitizing toothpaste, which will necessitate several treatments before pain is mitigated. A trip to the dentist can also help quell discomfort since your doc can apply an enamel-strengthening fluoride gel or seal the tooth root to prevent painful jolts every time you snack on something hot or cold.

The beauty of a sonic toothbrush is that it does the work for you. Levine says, "People who use a manual brush have to learn how to angle the bristles properly to get under the gum area at the root." Instead of using a gentle up-and-down stroke to remove plaque, he says, "Many people brush too hard and use a horizontal back-and-forth motion that can erode the gum area and accelerate tooth wear." Play it safe and invest in a sonic model, which costs anywhere from $90-$150 but often comes with a long-term warranty.