wisdom tooth

The third molar, commonly called wisdom tooth, is the most posterior of the three molars in each quadrant of the human dentition. The age at which wisdom teeth come through (erupt) is variable, but this generally occurs between late teens and early twenties. Most adults have four wisdom teeth, one in each of the four quadrants, but it is possible to have none, fewer, or more, in which case the extras are called supernumerary teeth. Wisdom teeth may become stuck (impacted) and not erupt fully, if there is not enough space for them to come through normally. Impacted wisdom teeth are still sometimes removed for orthodontic treatment, believing that they move the other teeth and cause crowding, though this is disputed.

Impacted wisdom teeth may suffer from tooth decay if oral hygiene becomes more difficult. Wisdom teeth that are partially erupted through the gum may also cause inflammation and infection in the surrounding gum tissues, termed pericoronitis. More conservative treatments, such as operculectomies, may be appropriate for some cases. However, impacted wisdom teeth are commonly extracted to treat or prevent these problems. Some sources oppose the prophylactic removal of disease-free impacted wisdom teeth, including the National Institute for Health and Care Excellence in the UK.