高リスク下顎第三大臼歯の歯冠抜去術：神経保護効果、長期予後、および臨床的論争
1State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Abstract:
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.
