College of Dentistry Patient Care: Tooth Extractions
Tooth extractions are done for many reasons. Wisdom teeth (or third molars) may need to be extracted if there is not enough room in the mouth for them to come in straight. Frequently these teeth are either fully or partially trapped in the bone (impacted) or under the gums. Your dentist may have to perform oral surgery to remove these teeth. Other teeth are removed to prepare for orthodontic treatment (braces) or to correct crowding of the teeth in the arch.
Unfortunately, many teeth will decay so badly that they cannot be restored. When a cavity reaches the level of the bone, almost always, the tooth must be extracted. Also, teeth that are fractured below the bone must be extracted.
In adults, loss of the support of the teeth due to periodontal disease is the most common reason for extraction. Periodontal disease can affect a single tooth or all of the teeth. In cases of severe periodontal disease all of the teeth may need to be extracted so that dentures can be made.