Re: Coronectomy

Purpose: Damage to the inferior alveolar nerve when extracting lower third molars is often caused by
the intimate relationship between the nerve and the roots of the teeth. The technique of coronectomy,
or intentional root retention, may minimize this problem.
Patients and Methods: Forty-one patients underwent coronectomy on 50 lower third molars with
follow-up of at least 6 months. The technique of coronectomy deliberately protected the lingual nerve
as part of the surgical procedure. All roots were left at least 3 mm below the buccal and lingual plates
of bone. All patients were radiographed preoperatively, immediately postoperatively, and after 6 months.
Results: There were no cases of inferior alveolar nerve–involved damage in this study of 41 patients
who underwent 50 coronectomies. There was 1 case of transient lingual nerve involvement, probably
from the use of the lingual retractor. One patient required subsequent removal of the roots of both lower
third molars because of failure to heal, and 1 patient required subsequent removal of a root because of
subsequent migration to the surface. Root migration was noted in approximately 30% of patients over a
6 month period.
Conclusion: Coronectomy appears to be a viable technique in those cases where removal of the whole
tooth might put the inferior alveolar nerve at considerable risk of damage. The technique appears to be
associated with a low incidence of complications, but subsequent migration of the roots may be an issue
in the long term.