Wisdom teeth is a term often used to describe the third molar teeth. Wisdom teeth are the final permanent teeth to erupt and usually do so during the ages of 18 to 21. Commonly there's insufficient space for the wisdom teeth to fully erupt into their correct position in the mouth or they erupt at an angle compared to the second molar teeth in front of them so they may become stuck or impacted. Sometimes the wisdom teeth may be partially erupted so only a small part of the tooth is showing, often a single tooth cusp, while the remainder of the tooth is below the gum. Wisdom teeth can be very difficult to reach and clean effectively and bacteria may find their way under the gum causing an infection. This results in pain and swelling in the gum around the tooth. In those areas that are most difficult to clean bacteria may cause decay on the back of the adjacent second molar tooth just below where the teeth contact which if left untreated can result in the loss of the second molar tooth as well as the wisdom tooth.