Stained, darkened, or yellowed teeth. The color of teeth may vary widely from one person to another. Discolored teeth may be due to hereditary factors. Yellowing of the teeth typically occurs with aging. Stains may be the result of habits that deposit color on the surface enamel of the teeth, such as smoking and tobacco use, which can permanently stain the teeth. Frequent drinking of coffee and tea, which contain tannin, can etch stains into the tooth enamel. Children may have green stains on the primary teeth, typically on the top front teeth, caused by natural bacteria in the mouth. These stains tend to disappear within a few years. Environmental exposure to copper and iron dust, and medications that contain related metal salts may cause green or brown discoloration of the teeth. Tetracycline, an antibiotic drug, used during the second half of pregnancy when teeth are developing in the fetus, or when a child is 8 years old or younger, can produce gray, yellow, or brown discoloration to varying degrees. A mottled appearance on the surface of the teeth, including bands or spots of varying shades of white, yellow, brown, or black, may indicate fluorosis (caused by the ingestion of excessive fluorides). Gray discoloration may be the result of dead tissue in the inner pulp of the tooth, a condition that requires root canal treatment.