Coronectomy, also termed intentional partial odontectomy, is a surgical technique in which the crown of an impacted mandibular third molar is deliberately removed while a portion of the root complex is left in situ, with the aim of avoiding direct surgical trauma to the inferior alveolar nerve (IAN). This narrative review synthesises the current evidence on the indications, surgical technique, outcomes, and controversies surrounding coronectomy of the mandibular third molar. A literature search of PubMed, Scopus, and the Cochrane Library was performed to identify original studies, systematic reviews, meta-analyses, and case series addressing coronectomy published from the introduction of the technique to the present. Relevant data on indications, radiographic risk assessment, operative technique, complication rates, root migration, and re-operation were extracted and synthesised narratively. Across the available literature, coronectomy is associated with a substantially lower incidence of IAN injury than complete surgical removal when the third molar root is judged radiographically to be in intimate contact with the mandibular canal, while rates of infection, dry socket, and postoperative pain are broadly comparable between the two approaches. Retained root fragments migrate away from the canal in the majority of cases, most markedly within the first six to twenty-four months, and re-operation is required in a minority of patients, most commonly for root mobility, exposure, or infection. Lingual nerve injury, pulpal disease, and failure of the technique intra-operatively (necessitating conversion to complete extraction) are recognised but infrequent. Coronectomy is a safe and clinically effective alternative to complete extraction for mandibular third molars judged to carry a high radiographic risk of IAN injury, provided that appropriate case selection, informed consent, and structured radiographic and clinical follow-up are observed. Long-term, adequately powered randomised evidence remains comparatively limited, and further prospective  research is warranted to refine patient selection criteria and to clarify the very long term fate of retained roots.

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