Also called third molars, are often extracted either before or after they come in. They commonly come in during the late teens or early 20s. They need to be removed if they are decayed, cause pain or if they are pushing your other teeth out of alignment. They may be out of their normal position or impacted if other teeth or bone are blocking them. These teeth often get stuck in the jaw (impacted) and do not come in. This can irritate the gum, causing pain and swelling. In this case, the tooth must be removed. Dentist will explain your situation, prescribe treatment and explain what to expect during and after the treatment.