To date, there are not universally accepted "official" classification and diagnostic criteria for the diagnosis of AO; yet, many have been proposed. According to the "Classification and Diagnostic Criteria for Headache Disorders, Cranial Neuralgias and Facial Pain" of the International Headache Society (IHS), AO is included, together with atypical facial pain, in diagnosis 12.8 "facial pain not fulfilling criteria in groups 11 and 12" (11: "headache or facial pain associated with disorder of cranium, neck, eyes, ears, nose, sinuses, teeth, mouth or other facial or cranial structures," 12: "cranial neuralgias, nerve trunk pain and deafferentation pain").
It is a diagnosis of exclusion, based on ruling out all other pathologies that originate from the teeth and adjacent structures. The diagnostic criteria are listed in Table 1 . In the "Comment" below the diagnostic criteria listed by the IHS, it is specified that "Pain may be initiated by operation or injury to face, teeth or gums but persists without any demonstrable local cause."
The American Academy of Orofacial Pain separates AO from facial pain corresponding to diagnosis 12.8, stating that advancements in understanding neuropathic pain allow us to better explain conditions such as AO, and avoid including it in the "waste basket" of "facial pain not fulfilling criteria in groups 11 and 12."
Graff-Radford and Solberg suggested instead a different collocation of AO (they proposed the term idiopathic toothache) in the IHS classification, within the diagnosis 11.6, headache or facial pain associated with disorder of "teeth, jaws and related structures." They suggested expanding this classification to:
11.6.5 Idiopathic toothache (atypical odontalgia)
They also suggested the diagnostic criteria reported in Table 2 . Those criteria were followed by Okeson in his symptom-based classification of orofacial pains, including AO in the category of deafferentation pain, a subcategory of continuous neuropathic pain.
In 1993, Marbach introduced other diagnostic criteria based mainly on the clinical characteristics of the pain ( Table 3 ), and called AO phantom tooth pain (PTP). A few years later, he stressed again points 5, 6, 7, 8, and 10 from his 1993 classification (see Table 3 ) as diagnostic criteria for AO. In a recent review, Marbach and Raphael presented a revision of the criteria with the purpose of aiding differential diagnosis rather than describing the syndrome ( Table 4 ). Merskey and Bogduk, in the Classification of Chronic Pain, defined AO as "severe throbbing pain in the tooth without major pathology." They also introduced these simple diagnostic criteria: "patient with history of tooth pain associated with endodontic therapy and/or extractions," and "remaining teeth while clinically sound and vital are tender to thermal stimuli and to percussion."
All the above-mentioned criteria for the diagnosis of AO differ in the details that are included by some authors yet overlooked by others; this results in slight variations in the precision of the differential diagnosis. Yet, it seems clear that AO is characterized by chronic pain that is usually continuous, and clinical, radiographic, and laboratory examinations that fail to reveal any organic pathology in the area where the pain is felt.
Our suggestion for the classification of AO is that it could be included in the IHS 12.1 classification "persistent (in contrast to tic-like) pain of cranial nerve origin," subdiagnosis "cranial neuralgias, nerve trunk pain, and deafferentation pain." The simplest diagnostic criteria, that include all the information needed for a correct diagnosis, are the criteria proposed by Pertes and colleagues. They comprehend the clinical description of the disease (presence or absence of signs and symptoms), response to diagnostic tests (radiographs, local anesthetic injection), and response to treatment (analgesics, surgery, dental procedures), neglecting other features that may be present, but are not essential for the diagnosis. Furthermore, these criteria do not assume that we know the etiology of AO, leaving the question open to future research as hypotheses remain different and controversial.
Headache. 2003;43(10) © 2003 Blackwell Publishing
Cite this: Atypical Odontalgia: A Review of the Literature - Medscape - Nov 01, 2003.