(See also Overview of Tooth Disorders.)
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. In the office, people remain awake and are given a local anesthetic or a sedative to calm them. Sometimes the surgery is done in a hospital. In a hospital, people are given a general anesthetic to make them fall asleep.