Coronectomy Versus Total Extraction for Third Molar Surgery: A Systematic Review and Meta-Analysis

Surgical extraction of impacted mandibular third molars near the inferior alveolar nerve (IAN) carries a risk of neurosensory injury. Coronectomy (intentional partial odontectomy) is a neuroprotective alternative, but concerns regarding long-term complications like root migration and the necessity for re-operation persist. This systematic review and meta-analysis evaluates the comparative safety and efficacy of coronectomy versus total surgical extraction. A literature search was conducted across PubMed, Embase, Scopus, and Cochrane Library for randomized controlled trials (RCTs) and prospective cohort studies comparing coronectomy to total extraction in high-risk lower third molars. Primary outcomes included IAN injury, dry socket, and infection. Secondary outcomes included pain, root migration, and re-operation rates. Data were pooled using random-effects models (REML) with Hartung-Knapp-Sidik-Jonkman adjustment. Trial sequential analysis (TSA) was performed for the primary outcome. The certainty of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Eight studies (three RCTs, five cohorts) comprising 1,488 teeth were included. Coronectomy significantly reduced the risk of IAN injury compared to total extraction (Peto OR 0.23, 95% CI (0.13, 0.39), p < 0.0001). TSA confirmed that the evidence for IAN injury prevention is conclusive. No statistically significant differences were found between groups for dry socket (RR 0.68, p = 0.22) or postoperative infection (RR 0.87, p = 0.71). Root migration was a common physiological sequela, but the pooled rate of re-operation to retrieve roots was low at 1.2% (95% CI (0.0%, 4.4%)). Coronectomy is a superior neuroprotective technique for high-risk mandibular third molars, significantly reducing nerve injury without increasing the risk of infection or dry socket compared to total extraction. While root migration is frequent, secondary surgical intervention is rarely required. Coronectomy is a highly effective surgical alternative that should be prioritized for radiographically high-risk impactions.