Atypical Odontalgia (AO) is a condition in which a tooth is very painful but nothing can be found wrong with it. The pain is continuous, usually burning, aching and sometimes throbbing and most often occurs in a maxillary (top) molar (back tooth) or in a tooth next to a molar. Since symptoms are very similar to those caused by a “toothache”, often numerous dental procedures are done. To complicate matters, these treatments may offer temporary relief from pain, only to have the pain return.
Symptoms
Symptoms include a continuous burning, aching pain in a tooth or in the bone/gum surrounding a tooth. Often there in increased sensitivity to pressure over the painful region. Diagnostic tests show no abnormality on x-ray and no obvious cause of tooth pain can be found.
Possible Causes
There is much speculation on possible causes, including psychological disorders, deafferentation (some sort of nerve damage / pathology), and vascular problems.
Psychological problems have been posed as a cause mainly based on studies in which no other physical cause for the pain could be found. A study done by Graff-Radford and Stolberg using the Minnesota Multiphasic Personality Inventory for facial pain patients found elevations of the MMPI scales were within standards for other medical populations, thus making it unlikely that psychological problems are a cause of AO or other facial neuralgia problems.
A vascular cause for AO similar to that described for migraine pain also seems unlikely because AO pain is continuous rather than episodic like migraine pain. However, one thermographic study of AO patients showed 100% of them having asymmetric heat emission patterns, suggesting vascular involvement of some sort causing some researchers to speculate that vascular involvement is a result of some other process.
Deafferentation may be a partial explanation. Many AO patients relate the onset of their pain to a dental procedure or tooth trauma.
Diagnosis
Diagnosis is based primarily on symptoms and on elimination of other possible disorders. Tests may include diagnostic dental x-rays, panorax, CAT scan and possibly MRI. If a nerve block does not result in pain reduction or if the results are ambiguous, then a diagnosis of AO should be considered.
Treatment
Pain medications such as analgesics and sedatives are not effective for AO. Surgery and other dental interventions rarely provide relief. Antidepressants medications can reduce AO pain which is probably due to their analgesic effects and not the antidepressant effects. AO patients are generally not depressed (Graff-Radford) .
Graff-Radford has noted a 75% reduction in pain among 25 AO patients using an average dose of 80mg of amitriptyline. He notes that a low dose of phenothiazine in combination with amitriptyline may increase pain reduction but that the potential serious side effects of phenothiazine may outweigh its benefits.
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