Impacted wisdom teeth

Impacted wisdom teeth
Other names	Impacted third molars
3D CT of an impacted wisdom tooth adjacent the inferior alveolar nerve prior to removal of wisdom tooth
Specialty	Dentistry, oral and maxillofacial surgery
Symptoms	Localized pain and swelling behind the last teeth
Complications	Infections, loss of adjacent teeth, cysts
Usual onset	Late teens, early 20s
Types	Full vs partially impacted, direction of impaction
Causes	Congenital
Diagnostic method	Examination, x-ray
Differential diagnosis	Other causes for dental pain, TMJ pain
Treatment	Good dental care, removal of wisdom teeth
Frequency	70-75% of the population

Impacted wisdom teeth is a condition where the third molars (wisdom teeth) are prevented from erupting into the mouth.^[1] This can be caused by a physical barrier, such as other teeth, or when the tooth is angled away from a vertical position.^[2] Completely unerupted wisdom teeth usually result in no symptoms, although they can sometimes develop cysts or neoplasms. Partially erupted wisdom teeth or wisdom teeth that are not erupted but are exposed to oral bacteria through deep periodontal pocket, can develop cavities or pericoronitis. Removal of impacted wisdom teeth is advised for the future prevention of or in the current presence of certain pathologies, such as caries (dental decay), periodontal disease or cysts. Prophylactic (preventative) extraction of wisdom teeth is preferred to be done at a younger age (middle to late teenage years) to take advantage of incomplete root development, which is associated with an easier surgical procedure and less probability of complications.^[3]

Impacted wisdom teeth are classified by their direction of impaction, their depth compared to the biting surface of adjacent teeth and the amount of the tooth's crown that extends through gum tissue or bone. Impacted wisdom teeth can also be classified by the presence or absence of symptoms and disease. Screening for the presence of wisdom teeth often begins in late adolescence when a partially developed tooth may become impacted. Screening commonly includes a clinical examination as well as x-rays such as panoramic radiographs.

Infection resulting from impacted wisdom teeth can be initially treated with antibiotics, local debridement or surgical removal of the gum overlying the tooth. Over time, most of these treatments tend to fail and patients develop recurrent symptoms. The most common treatment for recurrent pericoronitis is wisdom tooth removal. The risks of wisdom tooth removal are roughly proportional to the difficulty of the extraction. Sometimes, when there is a high risk to the inferior alveolar nerve, only the crown of the tooth will be removed (intentionally leaving the roots) in a procedure called a coronectomy. The long-term risk of coronectomy is that chronic infection can persist from the tooth remnants. The prognosis for the second molar is good following the wisdom teeth removal with the likelihood of bone loss after surgery increased when the extractions are completed in people who are 25 years of age or older. A treatment controversy exists about the need for and timing of the removal of disease-free impacted wisdom teeth. Supporters of early removal cite the increasing risks for extraction over time and the costs of monitoring the wisdom teeth. Supporters for retaining wisdom teeth cite the risk and cost of unnecessary surgery.

The condition can be common, with up to 72% of the Swedish population affected.^[4] Wisdom teeth have been described in the ancient texts of Plato and Hippocrates, the works of Darwin and in the earliest manuals of operative dentistry. It was the meeting of sterile technique, radiology, and anesthesia in the late 19th and early 20th centuries that allowed the more routine management of impacted wisdom teeth.