The Truth About All-Natural Teeth Whiteners

What to try: An in-office whitening treatment.

Why: Deep stains penetrate under the enamel and get stuck in the chicken-wire-like structure of your tooth. Professional-grade treatments use an effervescent whitening agent (a cousin of peroxide) that bubbles out the enamel and lifts the stain out of the chicken wire, explains Messina. (At-home whitening kits work the same way, but they're not nearly as powerful.) Be aware that stains aren't always due to a long-term love affair with coffee and red wine; Messina says that discoloration can also be a sign of a developmental issue, infection, receding gums (due to crowding, grinding or age) or periodontal disease. Your dentist can help get to the root causes of your stains and advise you on next steps.

What not to try: These Internet-approved fixes just don't work: pure bleach (it could burn the inside of your mouth); rinsing with lemon juice (it's an acid that can chemically dissolve enamel, Messina says); scrubbing strawberries on your teeth (they don't have any sort of magical plaque-destroying vitamins, but they do have some potent stain-producing acids and natural coloring).