Typically, adults have four wisdom teeth--one in the back of each quadrant. These teeth are also referred to as the third molar and numbered as 1, 16, 17, 32.
Wisdom teeth may begin to erupt around the age of 17. If there is not enough room in the mouth, wisdom teeth may remain impacted. They can cause such trouble as the shifting of other teeth or discomfort, thus requiring surgery to remove them.
(see Human Teeth)