Atypical Odontalgia: A Review of the Literature

Marcello Melis, DDS, RPharm; Silvia Lobo Lobo, DDS, MS; Caroline Ceneviz, DDS; Khalid Zawawi, BDS; Emad Al-Badawi, BDS, MS; George Maloney, DMD; Noshir Mehta, DMD, MDS, MS


Headache. 2003;43(10) 

In This Article

Differential Diagnosis

For a diagnosis of AO, other pathologies characterized by tooth pain need to be ruled out. Several have been listed: pulpal toothache,[8,16,23,24,25,30,80] trigeminal neuralgia,[7,21,24,25,26,30] temporomandibular joint disorders,[24,25,30] myofascial pain,[7,8,21,26] pretrigeminal neuralgia,[24,76] sinusitis,[7,8,21,25,30] ear and eye problems,[7] cracked tooth syndrome,[21] migrainous neuralgia,[7,8] temporal arteritis,[7,8] cranial neuralgias,[7,8] acute herpes zoster,[24,25,26,30] postherpetic neuralgia,[24,25,26,30] geniculate neuralgia,[24,25,26,30] arthritis of the temporomandibular joint.[24,25,30]

Probably the most difficult task is to distinguish between AO and toothache from pulpal origin. To help clinicians, 5 characteristics that are common to AO, but not common to pulpal toothache have been listed[16,23]: (1) constant pain in the tooth with no obvious source of local pathology; (2) local provocation of the tooth does not relate consistently to the pain. Hot, cold, or loading stimulation does not reliably affect the pain. (3) The toothache is unchanging over weeks or months. Pulpal pain tends to worsen or improve with time. (4) Repeated dental therapies fail to resolve the pain. (5) Response to local anesthesia is equivocal.

Thermography has been suggested by Graff-Radford et al as an additional aid in the diagnosis.[80] Patients with pulpal pain showed no thermographic difference in the territory of the pain complaint when compared to the opposite nonpainful side. Conversely, patients suffering from AO presented with either hot or cold thermograms.

It is usually easier to differentiate AO from trigeminal neuralgia because of the typical presentation of the latter. Marbach and Raphael highlighted the clinical and epidemiological characteristics of trigeminal neuralgia as follows:[24,25,26,30] (1) paroxysmal, unilateral, sharp, sudden, electrical, stabbing, recurrent pain confined to the distribution of one or more branches of the trigeminal nerve. Atypical odontalgia pain is dull and continuous. (2) Age of onset after the fourth decade, with a peak in the fifth and sixth decades. Atypical odontalgia is more frequent in women in their mid 40s. (3) Presence of trigger points that, stimulated by touch, elicit the pain. In addition, AO is usually preceded by a traumatic event to the tooth (root canal treatment, extraction, etc).

Other conditions that might be misdiagnosed as AO are temporomandibular disorders, including temporomandibular joint disorders and myofascial pain. In these pathologies, the pain is rarely limited to a tooth; it involves the preauricular and temporal regions, face, neck, and shoulder. Movements of the mandible (chewing, talking, yawning) commonly exacerbate the symptoms.[24] Trigger points that can elicit referred pain spontaneously and on palpation also characterize myofascial pain.[81]

Patients affected by pretrigeminal neuralgia have reported symptoms that are similar to those of AO:[82] burning, throbbing, and/or aching pain with no obvious dental pathology. In addition, pain frequently is reported to start after a dental procedure.[76] Nevertheless, we must note that the diagnosis of pretrigeminal neuralgia is a debatable issue, and that the name implies a pathophysiologic link to trigeminal neuralgia without scientific evidence.[24]

It is also important to recognize patients with migraine or cluster headache because AO has been reported to be associated with these types of headache. It is notable that pain increases during the headache episode in these individuals, and that the administration of some typical migraine (isometheptene,[12] methysergide,[12,78] flunarizine,[78,79] β-blockers[78]) or cluster headache (lithium[79]) medications often gives relief from the pain.[12,77,78,79]

Other diseases localized primarily in regions other than the teeth, such as eye, ear, and sinus, present usually with other accompanying symptoms that allow us to make a correct differential diagnosis.[7]

Attention should be paid when differentiating AO from the other conditions that could sometimes mimic such a disease,[7,8,21,24,25,26,30] knowing that the diagnosis can be difficult even after a thorough examination.