Persistent orodental pain, atypical odontalgia, and phantom tooth pain: when are they neuropathic disorders?

Abstract

Patients with unrelenting pain in the teeth, gingival, palatal or alveolar tissues often see multiple dentists and have multiple irreversible procedures performed and still have their pain. Up to one-third of patients attending a chronic facial pain clinic have undergone prior irreversible dental procedures for their pain without success. In these cases, if no local source of infectious, inflammatory, or other pathology can be found, then the differential diagnosis must include a focal neuropathic pain disorder. The common diagnoses given include the terms atypical odontalgia, persistent orodental pain, or if teeth have been extracted, phantom tooth pain. One possibility is that these pain complaints are due to a neuropathic alteration of the trigeminal nerve. There are several diagnostic procedures that need to be performed in any patient suspected of having a trigeminal neuropathic disorder including (1) cold testing of involved teeth for pulpal nonvitality; (2) a periapical radiograph examining the teeth for apical change; (3) a panoramic radiograph examining for other maxillofacial disease; (4) a thorough head and neck examination also looking for abnormality; (5) a cranial nerve examination including anesthetic testing which documents any increased or decreased nerve trigeminal nerve sensitivity and rules out other neurologic changes outside the trigeminal nerve; and (6) MRI imaging in some cases. Finally, when a nonobvious atypical toothache first presents, direct microscopic examination of the tooth for incomplete tooth fracture is also suggested. The majority of these patients are women over the age 30 with pain in the posterior teeth/alveolar arch. Multiple causes exist for sustained neuropathic pain including direct nerve injury (e.g., associated with fracture or surgical treatment), nerve injection injury, nerve compression injury (e.g., implant, osseous growth, neoplastic invasion) and infection-inflammation damage to the nerve itself. Sustained nerve pain is commonly seen in patients with psychiatric impairment. It may be that the unrelenting nature of the pain itself alters the patient's personality. Treatment includes pharmacologic medications which suppress nerve activity. The common medications used for atypical odontalgia and phantom tooth pain include gabapentin, tricyclics, topical anesthetics, and opioids. A list of these medications is provided in table form. Data suggest that once the patient has failed dental treatment and pain persists, the long-term outcome is less than 25 percent will have complete pain relief with treatment. With earlier treatment, better pain control, and improved nerve activity suppression medications, this should also prevent secondary psychiatric disease from developing and lower the number of inappropriate treatments.