There are two forms of tooth discoloration. Exogenous (surface staining) can be caused by frequent drinking of coffee, sodas, or tea, inadequate oral hygiene, some antibiotics, and use of tobacco products. A professional cleaning by a dentist can remedy exogenous tooth discoloration. In extreme cases, bleaching might be necessary.
The other form of tooth discoloration is endogenous (from within the tooth). This occurs if a tooth has been injured. Sometimes the nerve will gradually “die” and the tooth will become dark. A root canal treatment can sometimes cause a tooth to darken. Endogenous discoloration can be remedied by bonding, veneers, or crowns.