A coronectomy is a dental surgery that serves as an alternative to a complete tooth extraction, most commonly performed on lower wisdom teeth. The procedure involves removing the crown, or top part of the tooth, while intentionally leaving the roots embedded in the jawbone. This is a deliberate technique chosen by an oral surgeon to prevent specific complications.
When a Coronectomy is Recommended
A coronectomy is primarily recommended to avoid damaging the inferior alveolar nerve, which provides sensation to the lower lip, chin, and gums. The roots of lower wisdom teeth can grow very close to, or even become entangled with, this nerve. Radiographic imaging like X-rays or a cone-beam CT scan reveals this high-risk proximity.
During a traditional extraction, the force required to remove the entire tooth could bruise, stretch, or sever the nerve. This type of injury can lead to paresthesia, a condition that manifests as numbness, tingling, or altered sensation in the lip and chin. While often temporary, this numbness can be permanent in some instances.
By choosing a coronectomy, the surgeon leaves the roots undisturbed. This significantly reduces the chances of causing nerve injury. The procedure is only considered if the tooth is healthy and free from significant decay or infection, as leaving diseased roots behind could cause other complications.
The Coronectomy Surgical Process
The surgery begins with anesthesia, which may be local, intravenous sedation, or general, depending on the patient’s case. Once the area is numb, the surgeon makes an incision in the gum tissue to expose the underlying bone and the wisdom tooth. A dental drill is then used to remove a small amount of bone around the tooth.
Next, the surgeon sections the tooth, separating the crown from the roots just below the gumline. The crown is removed in pieces, ensuring the roots are not disturbed. If the roots become mobile during this stage, the surgeon may need to proceed with a full extraction. After the crown is removed, the remaining root surface is smoothed down to sit below the crest of the jawbone. The gum tissue is then repositioned and closed with stitches to cover the roots and facilitate healing.
Recovery and Aftercare
The recovery period following a coronectomy is similar to that of a standard wisdom tooth extraction. Swelling and mild to moderate pain are expected for several days and can be managed with prescribed pain medication and ice packs for the first 24 hours. These symptoms peak within the first two to three days and gradually subside.
Proper aftercare is important for preventing complications like infection. Patients are advised to maintain a soft food diet to avoid disturbing the surgical site. Gentle rinsing with warm salt water can begin the day after surgery to keep the area clean. It is important to avoid smoking or using straws, as the suction can dislodge the blood clot that forms in the socket, a painful condition known as dry socket. Normal tooth brushing can continue, though care should be taken around the stitches.
Long-Term Fate of the Tooth Roots
The primary question for most patients is what happens to the roots left in the jaw. In the majority of cases, the roots remain inert and stable within the bone, causing no future problems. The body’s natural healing process leads to bone growing over the roots, sealing them off from the oral cavity. This is the most common outcome, with the roots becoming an integrated, harmless part of the jaw structure.
A second possibility is a slow, gradual migration of the roots. Over a period of months to years, the roots may move upward, away from the inferior alveolar nerve and toward the surface of the gums. The peak rate for this migration often occurs within the first six months after the procedure. Should the roots erupt through the gum tissue, they can typically be removed in a simple, secondary procedure that carries a much lower risk of nerve damage.
A less frequent outcome is procedural failure, which can occur in a small percentage of cases. This might involve post-operative infection, persistent pain, or chronic inflammation around the retained roots. In these situations, a second surgery is required to remove the roots. Research indicates the need for a second surgery due to complications or migration is low, with removal needed in about 5% of cases, often due to migration rather than symptoms.