CORONECTOMY VERSUS COMPLETE EXTRACTION IN HIGH-RISK MANDIBULAR THIRD MOLARS: AN INTEGRATIVE LITERATURE REVIEW

Abstract

Introduction: impacted mandibular third molars in close radiographic relationship with the mandibular canal pose a relevant surgical challenge due to the increased risk of inferior alveolar nerve (IAN) injury during conventional extraction. Coronectomy, a technique consisting of crown removal with intentional retention of the roots, has become an established surgical alternative to reduce this risk. Objective: to compare the occurrence of IAN injury between coronectomy and complete extraction of high-risk mandibular third molars, also analyzing the main clinical outcomes associated with each approach. Methods: an integrative literature review was conducted following the methodological framework of Whittemore and Knafl, with searches in PubMed/MEDLINE, Scopus, Web of Science and the Cochrane Library. Primary studies and systematic reviews published mostly between 2021 and 2026 were selected, complemented by earlier references considered fundamental for the historical contextualization of the topic, including the pioneering randomized controlled trial by Renton et al. (2005) and the radiographic study by Rood and Shehab (1990). Results: the studies analyzed, including randomized controlled trials and systematic reviews with large pooled samples, presented consistent results regarding a lower occurrence of IAN injury after coronectomy compared with complete extraction. However, coronectomy may fail intraoperatively, requiring conversion to extraction in a subset of cases, and is also associated with migration of the remaining root a phenomenon more pronounced in younger patients and occasional need for surgical re-intervention, which proved proportionally less frequent than migration itself. Evidence regarding postoperative infection was heterogeneous across studies; some larger samples reported a numerically higher proportion of infection after coronectomy compared with extraction, a finding that should not be interpreted as a proven increase in risk, since not all studies reported statistical significance for this difference. Pain, alveolar osteitis and lingual nerve injury showed no consistent pattern of superiority of one technique over the other. Preliminary studies suggest possible applicability of coronectomy in elderly patients and in third molars with associated pathology, such as cysts and carious lesions, although the small number of studies in these subgroups does not yet allow generalization. Relevant overlap of primary studies used by the different systematic reviews included was also observed, which reduces the degree of independence among the pooled estimates reported in the literature. Conclusion: the available evidence indicates that coronectomy is associated with a lower occurrence of IAN injury in high-risk mandibular third molars and may constitute an alternative to complete extraction in selected cases. Its indication should be individualized, taking into account the possibility of root migration, eventual re-intervention, and the need for prolonged clinical and radiographic follow-up, in addition to the heterogeneity of the evidence on infection. Multicenter randomized clinical trials and long-term follow-up are needed to consolidate these observations.