Your teeth can become discolored by stains on its surface or by changes in the tooth material. Dentists divide discoloration into three main categories:
This occurs when the outer layer of the tooth (the enamel) is stained by coffee, wine, cola or other drinks or foods. Smoking also causes extrinsic stains.
This is when the inner structure of the tooth darkens or gets a yellowish tint. Causes include excessive exposure to fluoride during early childhood, the maternal use of tetracycline antibiotics during the second half of pregnancy and the use of tetracycline antibiotics in children 8 years old or younger.
This is a combination of extrinsic and intrinsic factors. In addition to stains caused by foods or smoking, the dentin naturally yellows over time. The enamel that covers the teeth gets thinner with age, which allows the dentin to show through. Chips or other injuries to a tooth can also cause discoloration, especially when the pulp has been damaged.