An impacted tooth is a tooth that fails to fully pass through the gums.

Teeth start to pass through the gums (emerge) during infancy, and again when the primary (baby) teeth are replaced by the permanent teeth.

If a tooth fails to emerge, or emerges only partially, it is considered to be impacted. The most common teeth to become impacted are the wisdom teeth (the third set of molars). They are the last teeth to emerge, usually between the ages of 17 and 21.

An impacted tooth remains stuck in gum tissue or bone for various reasons. It may be that the area is just overcrowded and there's no room for the teeth to emerge. For example, the jaw may be too small to fit the wisdom teeth. Teeth may also become twisted, tilted, or displaced as they try to emerge, resulting in impacted teeth.

Impacted wisdom teeth are very common. They are often painless and cause no apparent trouble. However, some professionals believe an impacted tooth pushes on the next tooth, which pushes the next tooth, eventually causing a misalignment of the bite. A partially emerged tooth can trap food, plaque, and other debris in the soft tissue around it, leading to inflammation and tenderness of the gums and unpleasant mouth odor. This is called pericoronitis.

• Bad breath
• Difficulty opening the mouth (occasionally)
• Pain or tenderness of the gums (gingiva) or jaw bone
• Prolonged headache or jaw ache
• Redness and swelling of the gums around the impacted tooth
• Swollen lymph nodes of the neck (occasionally)
• Unpleasant taste when biting down on or near the area
• Visible gap where a tooth did not emerge

Your dentist will look for swollen tissue over the area where a tooth has not emerged, or has only partially emerged. The impacted tooth may be pressing on nearby teeth. The gums around the area may show signs of infection such as redness, drainage, and tenderness. As gums swell over impacted wisdom teeth and then drain and tighten, it may feel like the tooth came in and then went back down again.

Dental x-rays confirm the presence of one or more teeth that have not emerged.

No treatment may be needed if the impacted tooth is not causing any problems.

Over-the-counter pain relievers may help if the impacted tooth causes discomfort. Warm salt water (one-half teaspoon of salt in one cup of water) or over-the-counter mouthwashes may be soothing to the gums.

Removal of the tooth (extraction) is the usual treatment for an impacted tooth. This is usually done in the dentist's office, but difficult cases may require an oral surgeon. Antibiotics may be prescribed before the extraction if the tooth is infected.

Impacted teeth may cause no problems for some people and may never require treatment. Treatment is usually successful when it does cause symptoms.

It is often preferable to have wisdom teeth removed before age 30 due to the flexibility of bone, which will allow an easier removal and better healing. As a person ages, the bone becomes more rigid and complications can develop.

Complications of an impacted tooth include:

• Abscess of the tooth or gums
• Chronic discomfort in the mouth
• Infection
• Malocclusion of the teeth
• Plaque trapped between teeth and gums

Call your dentist if there is an unemerged tooth (or partially emerged tooth) and pain in the gums or other symptoms have developed.