Wisdom teeth, or third molars, are the last permanent teeth to appear in the mouth. These teeth usually appear between the ages of 17 and 25. Some people never develop wisdom teeth. For others, wisdom teeth erupt normally — just as their other molars did — and cause no problems.
Many people develop impacted wisdom teeth — teeth that don't have enough room to erupt into the mouth or develop normally. Impacted wisdom teeth may erupt only partially or not at all.
An impacted wisdom tooth may:
Grow at an angle toward the next tooth (second molar).
Grow at an angle toward the back of the mouth.
Grow at a right angle to the other teeth, as if the wisdom tooth is "lying down" within the jawbone.
Grow straight up or down like other teeth but stay trapped within the jawbone.