Coronectomy for high-risk mandibular third molars: neuroprotection efficacy, long-term outcomes, and clinical controversies.

Coronectomy, a surgical procedure involving intentional crown removal with root retention of mandibular third molars at high risk of inferior alveolar nerve injury, represents a validated nerve-sparing alternative to complete extraction. This review summarizes evidence demonstrating its superior neuroprotective efficacy: Coronectomy reduces inferior alveolar nerve injury risk by 87% (0%-0.65% vs. 3.7%-19% in conventional extraction), with significantly lower rates of permanent sensory deficit (0.6% vs. 0.9%). Long-term outcomes (>5 years) reveal predictable root migration (>90% of cases; mean 2.5-4.6 mm, predominantly within 6-12 months), minimal chronic pain (0% after 3 years), and enhanced bone regeneration at the distal aspect of adjacent second molars (mean gain: 3.2-3.5 mm). Secondary extraction rates remain low (3.1%-5.4%), primarily indicated for root exposure (2.1%-3.5%) or infection (0.3%-1.6%). Key controversies include the contraindication of routine root canal treatment (failure rate: 87.5% vs. 12.5% without) and emerging two-stage extraction techniques. Strict cone beam computed tomography-guided selection criteria are critical to success. Future priorities include migration prediction models and bioactive material-enhanced healing. Taken together, coronectomy represents a clinically robust strategy for high-risk mandibular third molars when balancing nerve preservation against manageable complications.