Abstract
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 longterm fate of retained roots.