Several factors can affect the color of your teeth. While you have some control over certain causes, others occur naturally, like aging. Antibiotic use during childhood or exposure to high levels of fluoride or tetracycline can lead to dull or discolored teeth later in life. Coffee, tea, and any food or drink with tannins can leave behind stains on your teeth. Smoking or chewing tobacco discolors teeth. Genetics play a part in tooth color, and some people are predisposed to off-colored teeth. Aging contributes to tooth discoloration because your teeth naturally darken as you get older.