page_title: Wisdom tooth
section_title: Clinical significance
hierarchical_section_title: Wisdom tooth / Clinical significance
caption_attribution_description: English: RVG / Intraoral Periapical Xray of Impacted Lower Right Third Molar No. 48 (Wisdom Tooth) of 28 years old women
context_page_description: A wisdom tooth or third molar is one of the three molars per quadrant of the human dentition. It is the most posterior of the three. The age at which wisdom teeth come through is variable, but 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 get stuck against other teeth if there is not enough space for them to come through normally. While the impaction does not cause movement of other teeth, it can cause tooth decay if oral hygiene becomes more difficult. Wisdom teeth which are partially erupted through the gum may also cause inflammation and infection in the surrounding gum tissues, termed pericoronitis. Wisdom teeth are often extracted when or even before these problems occur. However, some, including the National Institute for Health and Care Excellence in the UK, recommend against the prophylactic extraction of disease-free impacted wisdom teeth.
context_section_description: Wisdom teeth (often notated clinically as M3 for third molar) have long been identified as a source of problems and continue to be the most commonly impacted teeth in the human mouth. The oldest known impacted wisdom tooth belonged to a European woman of the Magdalenian period (18,000–10,000 BCE). A lack of room to allow the teeth to erupt results in a risk of periodontal disease and dental cavities that increases with age.  Less than 2% of adults age 65 years or older maintain the teeth without cavities or periodontal disease and 13% maintain unimpacted wisdom teeth without cavities or periodontal disease. 
  Impacted wisdom teeth are classified by the direction and depth of impaction, the amount of available space for tooth eruption and the amount soft tissue or bone that covers them.  The classification structure allows clinicians to estimate the probabilities of impaction, infections and complications associated with wisdom teeth removal. Wisdom teeth are also classified by the presence of symptoms and disease.
  Treatment of an erupted wisdom tooth is the same as any other tooth in the mouth. If impacted, treatment can be restoration, local treatment to the infected tissue overlying the impaction, extraction or coronectomy.
caption: Dental x-ray of impacted lower right wisdom tooth with a horizontal orientation
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