Dark pigments in foods, beverages, and cigarette smoke can bind to your enamel, staining the surface of your teeth. If you're concerned, you might try using a straw when you drink dark-colored juice or cola to minimize its contact with your teeth. Tannic acid, the bitter compound in coffee, tea, and wine, can also cause yellow or brown stains when it combines with other particles on your teeth. Dairy products and saliva help neutralize this acid, so add a splash of milk to your coffee and stimulate saliva production by chewing sugarless gum. No matter what you do, though, your teeth will yellow as you age.
Most teeth whitening products and treatments rely on the bleaching agent hydrogen peroxide.
This compound breaks down into highly active oxygen molecules called free radicals, which penetrate your enamel and dentin and unlock the pigments from both. Crowns and other dental work can't be bleached, so if you have capped teeth, think about whether you'd be willing to replace them to match your new pearly whites. Whitening Toothpastes Brushing with these toothpastes is only slightly more effective on superficial stains than using regular toothpaste or chewing sugarless gum. However, if you've already bleached your teeth, using a whitening toothpaste may keep them white longer. The combination may leave your mouth feeling squeaky clean, but the bleach is too weak to lighten teeth much, especially since it is on them only for as long as it takes to brush.