Impacted wisdom teeth are third molars at the back of the mouth that don't have enough room to emerge or develop 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.

Symptoms

Impacted wisdom teeth don't always cause symptoms. However, when an impacted wisdom tooth becomes infected, damages other teeth or causes other dental problems, you may experience some of these signs or symptoms:

• Red or swollen gums
• Tender or bleeding gums
• Jaw pain
• Swelling around the jaw
• Bad breath
• An unpleasant taste in your mouth
• Difficulty opening your mouth

Complications

Impacted wisdom teeth can cause several problems in the mouth:

• Damage to other teeth. If the wisdom tooth pushes against the second molar, it may damage the second molar or increase the risk of infection in that area. This pressure can also cause problems with crowding of the other teeth or require orthodontic treatment to straighten other teeth.
• Cysts. The wisdom tooth develops in a sac within the jawbone. The sac can fill with fluid, forming a cyst that can damage the jawbone, teeth and nerves. Rarely, a tumor — usually noncancerous (benign) — develops. This complication may require removal of tissue and bone.
• Decay. Partially impacted wisdom teeth appear to be at higher risk of tooth decay (caries) than other teeth. This probably occurs because wisdom teeth are harder to clean and because food and bacteria get easily trapped between the gum and a partially erupted tooth.
• Gum disease. The difficulty cleaning impacted, partially erupted wisdom teeth increases the risk of developing a painful, inflammatory gum condition called pericoronitis (per-ih-kor-o-NI-tis) in that area.

When to see a doctor

See your dentist if you experience symptoms in the area behind your last molar that may be associated with an impacted wisdom tooth.