Wisdom teeth, or third molars, generally erupt into the mouth between the ages of 17 to 24 years. These are normally the last teeth to erupt and mostly into a position closely behind the last standing teeth (second molars). Space for these teeth to erupt can be limited and more than other teeth, wisdom teeth often fail to erupt or erupt only partially. Failure of the third molars to fully erupt is often due to impaction of the wisdom teeth against the second molars (teeth directly in front of the wisdom teeth). This occurs when the second molars are blocking the path of eruption of the third molar teeth and act as a physical barrier preventing further eruption. An impacted wisdom tooth is called asymptomatic if the patient does not experience signs or symptoms of pain or discomfort associated with this tooth.
Impacted wisdom teeth may be associated with pathological changes, such as swelling and ulceration of the gums around the wisdom teeth, damage to the roots of the second molars, decay in the second molars, gum and bone disease around the second molars and the development of cysts or tumours. General agreement exists that removal of wisdom teeth is appropriate if symptoms of pain or pathological conditions related to the wisdom teeth are present. This review found no evidence to support or refute routine prophylactic removal of asymptomatic impacted wisdom teeth in adults. The only included trial provided no evidence that removal of impacted wisdom teeth has an effect on late crowding of front teeth.