Wisdom teeth are also referred to as third molars and usually erupt between 17-25 years of age. Anthropological studies show that wisdom teeth erupt in order to compensate for the excessive wear and forward drifting of teeth due to the rough diet of early humans. But modern diet is soft and refined and excessive wear of teeth is not observed. So, as a result there is no room for wisdom teeth to erupt.
A tooth becomes impacted when there is lack of space in the dental arch. The tooth becomes essentially locked in place by the overlying gum, bone or another tooth. A tooth may be partially impacted (which means a portion of it has broken through the gum) or totally impacted (when it is unable to break through the gum at all.)
There can be numerous problems depending on the type of impaction. Partially impacted wisdom teeth cause the overlying gum tissue to become inflamed and irritated. So, there will be food lodgment in the area which may eventually lead to tooth decay on both the wisdom tooth and the tooth next to it. In such a case, failure to remove the wisdom tooth in a timely manner will necessitate root canal treatment on the tooth adjacent to it. The area can also become infected and the infection can spread to the muscles that help to open the mouth leading to restricted opening of the mouth, stiffness and illness. The pressure from the erupting wisdom tooth may move other teeth and disrupt the alignment of teeth.
Wisdom teeth are easier to remove when the patient is younger, since their roots are not completely formed, the surrounding bone is softer, and there is less chance of damaging nearby nerves or other structures. Removal of wisdom teeth at a later age becomes more complicated as the roots have fully developed (may involve the nerve) and the jawbone is denser. Also, early removal will ensure optimal and less complicated healing. For some patients, the wisdom teeth may erupt normally and will properly align in the arch. In such instances, the wisdom teeth can be retained with proper home care.