Neuropathy of the infraorbital area following rapid palatal expansion: A case report

RATIONALE: Neuropathic pain in the orofacial region, although relatively uncommon, can occur after dental procedures performed in trigeminally innervated areas. Miniscrew-assisted rapid palatal expansion (MARPE) is widely adopted to correct maxillary transverse deficiency in adults and is generally safe; however, neurosensory complications are rarely documented. This case highlights infraorbital neuropathy following MARPE, underscoring the need for clinical vigilance. PATIENT CONCERNS: A healthy 28-year-old female presented with numbness and tenderness on the left midface approximately 5 weeks after MARPE appliance placement. Her symptoms included hypesthesia in the zygomatic, upper lip, philtral, and palatal regions, and palpation-induced pain in the buccal mucosa and lower lip. The discomfort was described as dull and throbbing, partially numb, provoked by touch but not by thermal stimuli, with a visual analog scale score of 2 to 3. DIAGNOSES: Clinical examination revealed normal oral function and painless maximal opening. Sensory testing demonstrated marked asymmetry: reduced direction discrimination (30% vs 100%), abnormal 2-point discrimination (perceiving 1 point as 2), elevated pressure pain threshold (60 g vs 30 g), and diminished cold perception, while contact threshold remained symmetrical. Standard panoramic and Waters' radiographs showed no bony abnormalities. A provisional diagnosis of left maxillary trigeminal neuropathy, localized to the infraorbital nerve distribution, was made. INTERVENTIONS: Pharmacological treatment was initiated with gabapentin titrated to 300 mg 3 times daily, a short course of oral prednisolone, and subsequent introduction of low-dose amitriptyline for enhanced neuropathic pain control. Medication was well tolerated except for mild oral dryness and drowsiness, which resolved with tapering. OUTCOMES: Serial follow-up over 5 months demonstrated progressive reduction in neurosensory deficits, with near-complete resolution by the third month and full recovery without recurrence at the fifth month. LESSONS: This case illustrates that MARPE, while effective and generally safe, can occasionally induce neuropathic complications extending beyond palatal branches to involve the infraorbital pathway. Mechanical stress redistribution in skeletally mature patients likely contributes to this outcome. Careful monitoring for atypical sensory changes, early recognition, and timely pharmacological intervention are essential to optimize prognosis. Further research is warranted to clarify biomechanical mechanisms and risk factors for trigeminal nerve injury during orthodontic maxillary expansion.