Pathophysiology of referred pain in dentistry: a case report.

This article presents the clinical case of a 42-year-old woman with chronic pain in her left temporomandibular joint (TMJ) and limited mouth opening. The patient also reported anxiety and difficulty sleeping. Cone beam computed tomography revealed impacted maxillary third molars and hypertrophy of the nasal turbinates. An auriculotemporal nerve block performed with 2% lidocaine decreased the pain but did not eliminate it, suggesting that the TMJ was not the primary source of the patient's pain. At a follow-up appointment 24 hours after the nerve block, infiltration anesthesia was administered via a simple buccal injection at the level of the impacted left third molar. The infiltration anesthesia completely eliminated the TMJ pain, indicating that the patient was experiencing referred pain (also known as heterotopic pain). The patient's anxiety and disordered sleep (possibly the result of hypopnea arising from hypertrophic nasal turbinates) could have produced a central hypersensitivity that initiated or exacerbated the referred pain. The patient was advised to consult an otorhinolaryngologist to evaluate her respiratory and sleep problems and a psychiatrist to evaluate her anxiety state. In addition, extraction of the third molars and continued dental follow-up were proposed. Dentists may encounter patients with chronic referred pain in daily practice. Additional research is needed to better understand the mechanisms of referred pain and contributory psychological factors, which would allow dentists to identify and apply the best treatment strategies for these patients.