The wisdom teeth, also known as third molars, are the last teeth to emerge in the mouth, typically appearing between the ages of 17 and 25. Often, the jaw does not have enough space to accommodate these final molars, causing them to grow in at an angle or become trapped. This inability to fully erupt is known as impaction, frequently leading to the tooth growing “sideways” beneath the gum line. The decision to remove an impacted wisdom tooth is a complex assessment based on the tooth’s specific position, whether it is causing disease, and the patient’s overall health.
Defining Impacted Wisdom Teeth
An impacted third molar is the clinical term for a wisdom tooth prevented from emerging properly by bone, gum tissue, or another tooth. Impaction is classified by the tooth’s orientation and its depth of entrapment. Orientation is described by the direction the crown of the tooth is angled relative to the second molar directly in front of it.
The most common orientation is mesioangular impaction, where the tooth tilts forward toward the front of the mouth. In contrast, a distoangular impaction means the tooth is angled backward toward the throat. A truly “sideways” tooth is a horizontal impaction, which lies parallel to the jawbone and pushes directly into the root of the adjacent second molar. Finally, a vertical impaction is correctly oriented but remains trapped beneath the gum and bone due to a lack of space.
The depth of impaction determines how much tissue covers the tooth, impacting the difficulty of removal and the risk of infection. Impactions are classified by depth: soft tissue (covered only by gum tissue), partial bony (partially encased by jawbone), and full bony (completely covered and surrounded by bone).
Criteria for Necessary Surgical Removal
The presence of an impacted wisdom tooth alone does not necessitate removal, but certain pathological conditions make extraction mandatory. When an impacted tooth causes recurring pain, swelling, or infection, particularly pericoronitis, surgical removal is typically required. Pericoronitis is an inflammation of the gum tissue that partially covers a wisdom tooth, creating a trap for bacteria and food debris that leads to repeated infection.
Damage to the neighboring second molar is another major reason for extraction. A horizontally or mesioangularly impacted tooth can exert pressure causing root resorption (gradual breakdown of the adjacent tooth’s root). The hard-to-clean space between the impacted tooth and the second molar can also lead to decay (caries) on both teeth. This localized decay threatens the stability of the functional tooth.
The development of fluid-filled sacs, known as odontogenic cysts, or, in rare instances, tumors around the crown of the impacted tooth requires immediate removal. These lesions grow slowly but can progressively destroy the surrounding jawbone and damage nearby nerves. Finally, a dentist may recommend extraction if the impacted tooth is interfering with planned or existing orthodontic treatment, eliminating a potential source of pressure that could compromise the alignment of the other teeth.
Managing Asymptomatic Impacted Teeth
When an impacted wisdom tooth is not causing symptoms or active disease, the decision is made between prophylactic removal and conservative management (continued observation). Prophylactic removal, or preventative extraction, is often recommended in younger adults (ages 15 to 22) because the roots are not fully developed and the surrounding bone is less dense. This allows for an easier procedure, a lower risk of post-operative complications, and faster healing.
Conservative management involves retaining the tooth and monitoring it with regular check-ups and periodic X-rays to detect problems early. This approach is favored when the risks of surgery, such as potential nerve damage or complications from anesthesia, outweigh the immediate benefit of removal. Retaining an asymptomatic tooth carries the risk of late-onset pathology, such as developing gum disease or the tooth becoming more difficult to remove in later decades.
The decision relies heavily on an assessment of individual risk factors, including the proximity of the tooth to the main jaw nerve, the degree of impaction, and the patient’s preference. There is insufficient evidence to support the routine prophylactic removal of all asymptomatic, disease-free impacted wisdom teeth in adults. Patients who choose observation must commit to a schedule of routine imaging to ensure the tooth remains free of disease.
What to Expect During and After Extraction
Wisdom tooth removal is typically performed as an outpatient procedure by an oral surgeon or a general dentist. The surgery usually involves a form of sedation ranging from local anesthesia to general anesthesia, depending on the complexity of the impaction and the patient’s anxiety level. For impacted teeth, the surgeon makes an incision in the gum tissue to access the tooth and may need to remove a small amount of bone surrounding the tooth.
The tooth is often divided into smaller pieces to minimize the amount of bone removal. Once the tooth is extracted, the surgical site is cleaned, and sutures are placed to help the gums heal. The procedure itself often takes only a few minutes per tooth, though the total time in the office is longer due to preparation and recovery.
Post-operative care is crucial for preventing complications, most notably alveolar osteitis, or dry socket. This painful condition occurs when the blood clot in the empty socket fails to form or becomes dislodged. Patients must avoid sucking actions, such as using straws or smoking, for at least three to five days to protect the clot.
Swelling and discomfort are expected, managed with prescription or over-the-counter medication, often beginning before the local anesthetic wears off. Applying ice packs to the face for the first 24 hours minimizes swelling. A soft diet (including mashed potatoes, yogurt, and soup) is necessary for the first few days. Patients should gently rinse the mouth with warm salt water beginning 24 hours after surgery to keep the area clean.