Abstract
Objective: Injury to branches of the trigeminal nerve, particularly the inferior alveolar and
lingual nerves, is a recognised complication of both mandibular third molar surgery and
endodontic treatment. The purpose of this narrative review is to summarise current evidence
on the classification, incidence, risk factors, diagnosis, and management of nerve injury —
with particular emphasis on neuropraxia, the mildest and most common form — arising
from these two common dental procedures.
Methods: A narrative review of the English-language literature was conducted using
PubMed/MEDLINE and the Cochrane Library, employing combinations of the keywords
―neuropraxia‖, ―inferior alveolar nerve injury‖, ―lingual nerve injury‖, ―third molar
surgery‖, ―endodontic nerve injury‖, and ―sodium hypochlorite accident‖. Systematic
reviews, meta-analyses and cohort studies were prioritised and supplemented with relevant
case reports and case series where higher-level evidence was unavailable.
Results: Reported incidence of inferior alveolar nerve injury after third molar surgery
ranges from 0.35% to 8.4% for transient deficits and is generally below 2% for permanent
deficits. Lingual nerve injury is closely linked to surgical technique, with lingual flap
retraction and the lingual split technique associated with a several-fold increase in
temporary injury compared with a buccal-only approach. The great majority of these
injuries represent neuropraxia and resolve spontaneously within weeks to a few months.
Endodontic-related nerve injury is less common but can follow chemical (sodium
hypochlorite, calcium hydroxide, sealer extrusion) or mechanical (overinstrumentation,
overfilling) insult, and its course is more variable, at times accompanied by neuropathic
pain. Cone-beam computed tomography improves preoperative risk stratification in
radiographically high-risk cases. Management ranges from observation and
pharmacological neuropathic pain control to surgical removal of extruded material and
microsurgical nerve repair, with the best outcomes generally reported when repair is
undertaken within approximately twelve months of injury.
Conclusion: Neuropraxia accounts for the majority of nerve injuries encountered in third
molar surgery and endodontics and carries a favourable prognosis. Careful preoperative risk
assessment, judicious technique selection, prompt recognition of injury, objective
neurosensory testing, and timely referral for specialist or microsurgical intervention when
indicated together optimise clinical outcomes and reduce medicolegal exposure.