Impacted wisdom teeth are third molars at the back of the mouth that don't have enough room to emerge or grow normally.
Wisdom teeth are the last adult teeth to come into the mouth (erupt). Most people have four wisdom teeth at the back of the mouth — two on the top, two on the bottom.
Impacted wisdom teeth can result in pain, damage to other teeth and other dental problems. In some cases, impacted wisdom teeth may cause no apparent or immediate problems. But because they're hard to clean, they may be more vulnerable to tooth decay and gum disease than other teeth are.
Impacted wisdom teeth that cause pain or other dental complications are usually removed. Some dentists and oral surgeons also recommend removing impacted wisdom teeth that don't cause symptoms to prevent future problems.