An interesting article titled “Coronectomy of the Mandibular Third Molar: A Retrospective Study of 185 Procedures and the Decision to Repeat the Coronectomy in Cases of Failure,” appears in the April 2015 issue of the Journal of Oral and Maxillofacial Surgery written by Boaz Frenkel and et. al. (vol. 73, issue 4). The article seeks to evaluate the success rate of coronectomy and if failure occurs, retreatment.
Coronectomy is an alternative extraction technique of wisdom teeth to prevent inferior alveolar nerve (IAN) injury in cases of root proximity to the IAN or complicated root anatomy of the mandibular wisdom teeth. The technique seeks to extract the crown of the mandibular wisdom teeth and leave the roots intact. Coronectomy is not without risks and complications and things such as infection, dry socket, and pain can occur in addition to healing that doesn’t fully resolve and root eruption. Coronectomy failure can be treated with reoperation (removal of the residual roots) or in some cases repeat coronectomy can occur.
The study included 173 patients undergoing 185 coronectomy procedures between December, 2008, and October, 2012, at Sheba Medical Center in Israel. Coronectomy was performed when orthopantographic imaging indicated close proximity of the roots of the mandibular wisdom teeth to the IAN or when the patient was very anxious owing about surgical extraction. The most common cause leading to coronectomy was due to pericoronitis. Patients were later evalulated 4 weeks, 6 months, and 12 months after the procedures, but not all patients presented for follow ups at these times.
Some of the results from the study when patients were evalulated four weeks after coronectomy included that
“Sixteen patients (15%) complained of pain 1 month after surgery, whereas 85 (85%) patients were pain free. Inflammatory processes were viewed in 15 coronectomy sites (14%). Only 1 patient reported hypoesthesia of the lower lip. Three coronectomy procedures were considered failures and the residual roots were removed (reoperation) owing to an inflammatory process with pus discharge. In 3 other cases, a normal healing process followed a repeat coronectomy performed after the retention of enamel was diagnosed.”
In their analysis the authors explored the migration of residual roots after 6 and 12 months and found statistical differences with younger patients having more migration. There was also one temporary IAN injury in the study. Overall the authors said 10 of the 185 cases failed. In the study their were six failures due to enamel retention and in four of these cases coronectomy was repeated. In the other 6 failures (not resolved by repeat coronectomy) the residual roots were removed.
The authors feel that coronectomy is a safe procedure to extract wisdom teeth and minimize nerve injury. Even so, the authors do recommend follow up 1 year after coronectomy is performed to make sure nothing that can not be corrected is occurring.