Safety of Coronectomy versus Surgical Extraction: A Randomized Control Trial

Statements of the problem: Evaluation of coronectomy of the lower third molars have been reported in the literature to be a safe way to avoid inferior alveolar nerve (IAN) damage with lower third molars being in close proximity to the nerve. The aim of this study was to further contribute to the literature to compare coronectomy with standard surgical extractions of the mandibular third molars in terms of efficacy, success, and safety.

Material and Methods: This was a randomized clinical 1-year trial that investigated 64 patients (120 teeth) who underwent either a surgical extraction or a coronectomy. Patients who exhibited high-risk signs of IAN injury on panoramic imaging were screened with a CBCT. On CBCT, the patients with any close relationship between the third molar and the inferior alveolar canal were eligible for enrollment in the study. Coronectomy or conventional surgical extraction was randomly chosen for each tooth and surgery was performed. The patient was brought in for postoperative evaluation 1 week, 1 month, 6 months, and 1 year after the surgery. Morbidities such as pain, infection, root eruption and sensory changes were evaluated at each appointment. After 1 year, a new CBCT scan was taken and evaluated for coronectomy cases. 

Data Analysis: Subjective analysis

Results: 64 patients (26 men, 38 women with a mean age of 26.3) with 54 coronectomies and 66 surgical extractions completed.  Out of the 54 coronectomies, 1.6% (3 teeth) required re-surgery due to mesial lipping of the enamel. 4 out of the 66 surgical extractions (2.64%) had dry socket, which was resolved with chlorhexidine irrigation and Alvogyl dressing. In the surgical extraction group 4 patients (2.64%) showed signs of neurapraxia, which resolved in 3 weeks. On the one year post-operative CBCT the average length of root migration in 54 cases was 2.3 mm

Conclusions: Overall, although we saw a total of 4 complications, none of the aforementioned teeth had any long-term neurosensory deficit in regards to the inferior alveolar nerve or lingual nerve.  We can conclude that both procedures are adequate in regards to safety when mandibular third molars are in close proximity to the inferior alveolar nerve. Further investigation with larger sample size will be beneficial to confirm the findings of this study. A long-term randomized controlled trial with a larger sample size is needed to assess and compare the incidence of root migration and infection rates.

References:

Renton T, Hankins M, Sproat C, et al. A randomized controlled clinical trial to compare the incidence of injury to the inferior alveolar nerve as a result of coronectomy and removal of mandibular third molars. Br J OralMaxillofac Surg 2005;43(1):7–12.

Pogrel MA, Lee JS, Muff DF. Coronectomy: a technique to protect the inferior alveolar nerve. J Oral Maxillofac Surg 2004;62:1447–52