title: Sodium hypochlorite-related injury with chronic pain sequelae.
abstract: BACKGROUND
  A 29-year-old woman visited a general dental residency clinic with a complaint of severe aching and burning facial pain with occasional sharp stabbing pain and persistent numbness. The symptoms had been present for seven months after sudden onset during endodontic irrigation with sodium hypchlorite. She was evaluated and treated by one of the authors, who was trained in orofacial pain management.
  
  
  METHODS
  The patient reported experiencing debilitating symptoms since the hypochlorite injury. She had been treated with methylprednisolone followed by antiseizure, anti-inflammatory and opioid medications prescribed by a neurologist. Examination and testing revealed static and dynamic mechanical allodynia along with neurological deficits on the left side of the face, implicating both peripheral and central pain mechanisms. The orofacial pain clinician made a diagnosis of peripheral painful traumatic trigeminal neuropathy involving all three branches of the left trigeminal nerve. The addition of an oral neurosensory stent and modification of medications reduced the patient's pain, resulting in improved function and quality of life.
  
  
  CONCLUSIONS
  Sodium hypochlorite irrigation may lead to injury and persistent neuropathic pain. Diagnosis and management of chronic orofacial pain require an understanding of pain mechanisms and appropriate treatment options. A multidisciplinary approach with clear communication among the general dentist, dental specialists, primary care physician and medical specialists often is necessary.
authors.affiliation: Dr. Matthews was in advanced clinical training, Department of Orofacial Pain and Sleep Medicine, School of Dentistry, Center for Health Sciences, University of California, Los Angeles, when this article was written. He now is an assistant professor, Department of Dental Medicine, University of New Mexico School of Medicine, Albuquerque. Address correspondence to Dr. Matthews, P.O. Box 1574, Los Alamos, N.M. 87544, e-mail jmattdent@aol.com.
authors.forename: Joseph
authors.initials: J
authors.lastname: Matthews
authors.affiliation: Dr. Merrill is an adjunct professor, Section of Orofacial Pain and Oral Medicine, School of Dentistry, Center for the Health Sciences, University of California, Los Angeles.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Merrill
mesh_terms: D000328:Adult; D059350:Chronic Pain / Q000139:chemically induced*; D005260:Female; D006801:Humans; D012973:Sodium Hypochlorite / Q000633:toxicity*
chemical_list: D012973:Sodium Hypochlorite
keywords: Trigeminal nerve; endodontic therapy; facial pain; irrigation; neuralgia; orofacial pain; postoperative pain; root canal