Facial Nerve Injury Complications During Inferior Alveolar Nerve Block: A Review Article

The Inferior Alveolar Nerve Block (IANB) is the most utilized regional anesthetic technique in dentistry, but it carries a rare risk of transient Facial Nerve (CN VII) palsy, reported at approximately 0.3\%.This motor complication manifests as unilateral facial weakness, drooping of the corner of the mouth, and critical inability to close the ipsilateral eye (lagophthalmos). The primary etiology is a technical error: the inadvertent deposition of local anesthetic directly into the parotid gland capsule, a consequence of overly deep or posterior needle placement . While immediate palsy is a chemical conduction block, delayed presentation is hypothesized to stem from localized ischemic neuritis and secondary edema. Management is focused on immediate patient reassurance, mandatory ocular protection (lubricants and patching) to prevent corneal damage , and the use of systemic corticosteroids to mitigate inflammation . The prognosis is excellent, with complete functional recovery commonly observed within eight weeks. Prevention relies on rigorous adherence to injection protocol, including aspiration, slow injection, and strict depth control to prevent posterior needle penetration .