Wisdom tooth
![](/Images/godic/202502/16/Weisheitszähne-11440.jpg")
![A wisdom tooth protrudes outwards from the gumline with inflamed tissue at the back (pericoronitis; green arrow)](/Images/godic/202502/16/38_pericoronitis_with_pus1440.jpg")
![Some problems which may or may not occur with third molars: A Mesio-impacted, partially erupted mandibular third molar, B Dental caries and periodontal defects associated with both the third and second molars, caused by food packing and poor access to oral hygiene methods, C Inflamed operculum covering partially erupted lower third molar, with accumulation of food debris and bacteria underneath, D The upper third molar has over-erupted due to lack of opposing tooth contact, and may start to traumatically occlude into the operculum over the lower third molar. Unopposed teeth are usually sharp because they have not been blunted by another tooth (attrition).](/Images/godic/202502/16/Lower_mandibular_third_molar_impaction_pericoronitis_diagram1440.jpg")
A wisdom tooth or third molar is one of the three molars per quadrant of the human dentition. It is the most posterior (most distal) of the three. Wisdom teeth generally erupt between the ages of 17 and 25. Most adults have four wisdom teeth (a third molar in each of the four quadrants), but it is possible to have fewer or more, in which case the extras are called supernumerary teeth. Wisdom teeth commonly affect other teeth as they develop, becoming impacted or "coming in sideways". They are often extracted when this occurs.