Healthy, normal permanent teeth are light ivory in color. Several conditions may cause them to become noticeably discolored, however.
- Surface stains: Certain foods, such as coffee, tea, and red wine, can stain the surfaces of your teeth. So can tobacco, whether smoked or chewed. These stains are likely to be concentrated in areas that are hard to keep clean by brushing, such as the gumlines and the spaces between your teeth. Usually, such stains can be removed through regular professional cleaning. If you are a heavy tea or coffee drinker or a habitual smoker, however, you may need to have your teeth cleaned more often than usual to keep them looking presentable.More troublesome are stains on tooth-colored composite fillings, of the kind used to restore the highly visible front teeth. Not only does the composite material discolor more readily than natural tooth enamel, but also stains are likely to work their way into the margins around fillings. Even professional cleaning may not remove them.
- Tetracycline stains: Certain chemical substances that are introduced into the body can stain the inner layer, or dentin, of the teeth. These deep stains cannot be removed by cleaning. Among the most severe dentin stains are those caused by the antibiotic tetracycline.Tetracycline and its various forms are useful against a wide range of infections. But if any one of them is taken by a woman during pregnancy, it may stain the developing primary teeth of her baby. If it is taken by a child under the age of eight, it may be absorbed by the developing permanent teeth, staining them orange, brown, or gray. The stain may affect the whole tooth, or it may appear as parallel, horizontal “stripes” or “ribbons,” alternating with more normal coloration.Fortunately, the danger of tetracycline staining is widely known, and most obstetricians and pediatricians now avoid prescribing this antibiotic whenever possible.
- Fluorosis: In some geographical areas, the water supply naturally contains rather large concentrations of fluorides. Drinking the water in these regions can cause a mottled grayish or brownish staining of the teeth that’s called fluorosis.Fluorosis is not caused by the artificial fluoridation of water or by professional fluoride applications or fluoride toothpaste or mouthwash, when used as directed. In all these uses of fluoride, its concentration is too low or exposure to it is too limited to cause staining.
- Developmental defects: Sometimes disease or other health problems interfere with the development of the teeth during childhood. The enamel of the teeth may develop irregularly or improperly. Some of the enamel on individual teeth may also be deficient in calcium and develop chalky-white spots popularly known as “headlights.”
- Diffusion from amalgam fillings: Silver amalgam, historically, the most common material that’s used for fillings, is largely a mixture of silver and mercury, plus small proportions of other metals. Chemical reactions in your mouth may cause a slight corrosion of those materials, to produce a gray stain that diffuses into the surrounding tooth enamel.
- Damaged pulp: In teeth that have been subjected to trauma, whether through accident or violence, or that have had root canal treatment, the blood vessels of the pulp may bleed into the surrounding dentin. Blood contains iron, which can darken teeth to a grayish or brownish color.
- Tooth wear: Though tooth enamel is the hardest substance in your body, it is not totally resistant to wear. With advancing years, parts of it may be worn thin, so that the darker dentin underneath becomes more visible. Several factors may be involved. Habitual grinding, or bruxing, of your teeth may wear off the tops of the crowns, exposing the dentin. Improper brushing may also abrade the tooth surfaces, while strong acids may erode them.
- Exposed roots: Periodontal disease or advancing age may cause your gums to recede from the necks of your teeth. This tends to expose the roots of the teeth, below the enamel. The protective cementum that covers the roots is thinner and more transparent than enamel, and reveals the darker dentin underneath.