Impacted teeth are teeth that are unable to emerge (erupt) properly from the gum.
Impaction is usually caused by the overcrowding of teeth, which leaves insufficient room for a new tooth to emerge. Impaction can occur when a baby tooth is lost before the new tooth is ready to emerge, which allows the remaining teeth to drift into the space reserved for the new tooth. However, most teeth that become impacted are wisdom teeth because they are the last permanent teeth to come in and the jaw lacks enough room to accommodate them.
Impacted teeth are likely to become infected and are of little use in chewing, so they are usually removed. Often the removal can be done in the dentist's office with the person remaining awake, with use of a local anesthetic or with sedation to calm the person. Sometimes the surgery is done in a hospital with the person asleep, with use of a general anesthetic.
Last full review/revision October 2008 by James T. Ubertalli, DMD