Teeth start to pass through the gums (emerge) during infancy. This happens again when permanent teeth replace the primary (baby) teeth.

If a tooth does not come in, or emerges only partially, it is considered to be impacted. This most commonly happens with the wisdom teeth (the third set of molars). They are the last teeth to erupt. They usually come in between the ages of 17 and 21.

An impacted tooth remains stuck in gum tissue or bone for various reasons. The area may be overcrowded, leaving 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. This results in impacted teeth.

Impacted wisdom teeth are very common. They are often painless and do not cause problems. However, some professionals believe an impacted tooth pushes on the next tooth, which pushes the next tooth. Eventually, this can cause a misaligned bite. A partially emerged tooth can trap food, plaque, and other debris in the soft tissue around it, which can lead to inflammation and tenderness of the gums and unpleasant mouth odor. This is called pericoronitis. The retained debris may also lead to the decay on the wisdom tooth or the neighboring tooth, or even bone loss.

There may be no symptoms of a fully impacted tooth. Symptoms of a partially impacted tooth may include:

• Bad breath
• Difficulty opening the mouth (occasionally)
• Pain or tenderness of the gums 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 an impacted wisdom tooth is not causing any problems. If the impacted tooth is somewhere towards the front, braces may be recommended to help put the tooth into proper position.

Over-the-counter pain relievers may help if the impacted tooth causes discomfort. Warm saltwater (one-half teaspoon or 3 grams of salt in one cup or 240 milliliters of water) or over-the-counter mouthwashes may be soothing to the gums.

Removal of the tooth is the usual treatment for an impacted wisdom tooth. This is done in the dentist's office. Most often, it will be done by 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 not need treatment. Treatment is most often successful if the tooth causes symptoms.

Having wisdom teeth removed before age 20 often has better results than waiting until you are older. This is because the roots are not yet fully developed, which makes it easier to remove the tooth and to heal better. As a person ages, the roots become longer and curved. Bone becomes more rigid, and complications can develop.

Complications of an impacted tooth can include:

• Abscess of the tooth or gum area
• Chronic discomfort in the mouth
• Infection
• Malocclusion (poor alignment) of the teeth
• Plaque trapped between teeth and gums
• Periodontal disease on the neighboring tooth
• Nerve damage, if the impacted tooth is near a nerve in the jaw called the mandibular nerve

Contact your dentist if you have an unemerged tooth (or partially emerged tooth) and you have pain in the gums or other symptoms.

Tooth - unemerged; Unemerged tooth; Dental impaction; Unerupted tooth

Campbell JH, Nagai MY. Pediatric dentoalveolar surgery. In: Fonseca RJ, ed. Oral and Maxillofacial Surgery. 3rd ed. St Louis, MO: Elsevier; 2018:chap 20.

Hupp JR. Principles of management of impacted teeth. In: Hupp JR, Ellis E, Tucker MR, eds. Contemporary Oral and Maxillofacial Surgery. 7th ed. St Louis, MO: Elsevier; 2019:chap 10.

Klene CA, Ferneini EM, Bennett JD. Oral Surgery for the pediatric patient. In: Dean JA, ed. McDonald and Avery's Dentistry for the Child and Adolescent. 11th ed. St Louis, MO: Elsevier; 2022:chap 29.

Updated by: Michael Kapner, DDS, General Dentistry, Norwalk Medical Center, Norwalk CT. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.