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.