Wisdom teeth are the last teeth to erupt within the mouth. When they align properly, room in the mouth is adequate, and surrounding gum tissue is healthy, wisdom teeth do not have to be removed. Unfortunately, this does not generally happen. The extraction of third molars are necessary when they are prevented from properly erupting within the mouth. They may grow sideways, partially emerge from the gum, and even remain trapped beneath the gum and bone. These teeth that are positioned beneath or partially beneath the gums and the jawbone are known as "impacted" teeth. Impacted teeth can take many positions in the bone as they attempt to find a pathway that will allow them to erupt successfully. These poorly positioned teeth can cause many problems. When they are partially erupted, the opening around the tooth allows bacteria to invade, and will eventually result in an infection. The result: swelling, stiffness, pain and illness. The pressure from the erupting wisdom tooth may move other teeth and disrupt the proper alignment of the other teeth. The most serious problems occur when tumors or cysts form around the impacted wisdom tooth, resulting in the destruction of the jawbone and/or adjacent teeth. Removal of the offending tooth or teeth usually resolves these problems. Early tooth extraction, typically in the teen years, is recommended to avoid such problems and to decrease the surgical risk involved with the procedure.