is not uncommon to see cases of non-odontogenic pain in a regular clinical
dental practice, it is one of the most challenging diagnoses for both dentist
and patient. As clinicians, it is important for dentists to have a thorough
knowledge of odontogenic and non-odontogenic causes of orofacial pain and the
need for careful diagnosis before undertaking any treatment.1 Since
persistent and chronic pain is more common in the head and neck region than in
any other part of the body, dentists are more likely to encounter these rather
complex cases in their practices.2 Due to the complexities and
diagnostic challenges, the misdiagnosis of neuropathic pain is common.3
On most occasions when unnecessary dental treatment is rendered to the patient,
it is done with the hope of relieving the pain.
purpose of this article is to review the literature of atypical odontalgia, to
discuss the pathophysiology, illustrate the complexities of diagnosing the
condition, and enumerate the treatment options. The literature search was done
by using pubmed.gov and scholar.google.com.
of its first description by English surgeon and pathologist John Hunter
(1728-1793) more than 200 years ago, the clinical condition of atypical
odontalgia was not universally accepted among dentists4 as a
pathology. McElin first reported atypical odontalgia5 in the Annals of Internal Medicine in 1947. The
term “phantom tooth pain” was first used in 1978, and since then the condition
has been validated as a clinical entity.6
atypical odontalgia is an accepted clinical condition, cases of AO are seldom
reported.6 One problem for the dentist in diagnosing neuropathic
pain has been the use of various terms ascribed by different investigators over
the years.7 The taxonomy of chronic pain syndromes has included the
terms “idiopathic odontalgia”,8 “neurovascular odontalgia”,9
and “oral neuropathic pain”.10 Even though there have been numerous
meetings among worldwide authorities on orofacial pain, there is no current
consensus on the taxonomy of the different forms of idiopathic orofacial pain,
which include stomatodynia, atypical odontalgia, atypical facial pain, and
facial arthromyalgia. These conditions on occasion are considered as separate
entities and are sometimes grouped together.11 Atypical odontalgia
has also been described as a localized form of atypical facial pain.23
The diagnosis and management of this condition can be difficult due to the
multifactorial nature of the problem, and a multidisciplinary approach can
assist the practitioner in diagnosis and treatment.12
odontalgia has been defined as severe throbbing pain in a tooth without any
pathology.25 The primary symptom of AO is pain located in a tooth or
tooth site, which may spread with time involving the entire maxilla or
mandible.26 Characteristically, AO presents as throbbing, persistent
pain in teeth or alveolar process for a prolonged period of time6
with an absence of any pathological, clinical, or radiological findings.4
AO has been reported to affect all ages, except children, with a preponderance
among women in their mid-forties and mostly affecting the maxillary molar and
premolars.14 Commonly, AO follows dental or surgical procedures such
as pulp extirpation, apicoectomy, tooth extractions, or exenteration of the
contents of the maxillary antrum,13 although it can be idiopathic.
The pain is chronic; sleep is undisturbed, and the patients may have brief
symptom-free periods on waking.5 The results of local anesthetic
injections and direct nerve blocks are mostly inconclusive, and patients rarely
find relief with analgesics, including narcotics.6,13 Several authors
have asserted that psychological factors are the underlying cause of atypical
odontalgia, but objective evidence is lacking to support this claim.15
Osteoporosis which appears with menopause and neuralgia-inducing cavitational
osteonecrosis (NICO) have also been linked to atypical facial pain.19
extensive research, the pathophysiology of atypical odontalgia still remains
uncertain. Pain is an unpleasant sensation, and nociception is a measurable
physiological event of a type usually associated with it. A nociceptor is a
sensory receptor that sends signals that cause the perception of pain in
response to a potentially damaging stimulus. In AO, different neuropathic
mechanisms may be at work, among them:
phenotypic changes and ectopic activity from the nociceptors,
sensitization possibly maintained by ongoing activity from initially damaged
sympathetic abnormal activity,
alteration of segmental inhibitory control, and
or hypoactivity of descending controls.19
conjectured the similarity in etiology of the pain of atypical odontalgia with
phantom limb pain. The most accepted theory explaining the pathophysiology of
AO is deafferentation, which is the elimination or interruption of sensory
nerve fibers, caused by traumatic injury with changes occurring at the level of
the peripheral, central, and autonomic nervous systems.18,19,24
neuromatrix theory of pain proposed by Melzack has also been described in the
literature to explain the pathophysiology of this pain. The neuromatrix, which
is genetically determined and modified by sensory experience, is the primary
mechanism that generates the neural pattern that produces pain. Its output
pattern is determined by multiple influences, of which the somatic sensory
input is only a part, that converge on the neuromatrix.
investigators have proposed many diagnostic criteria for AO. However, the
diagnosis is made by exclusion.4 The diagnostic criteria proposed by
S.B. Graff-Radford and W.K. Solberg can be a helpful tool (Table One). This
diagnostic criteria is very simple and focuses on all the typical
characteristics of AO.24 In 1995, Pertes and colleagues revised the
criteria and included the non-responsiveness of pain to dental treatment.17
successful diagnosis of orofacial pain depends upon the following:28
1. An accurate and detailed history of the pain.
2. A detailed clinical examination of the face and associated organs.
3. A thorough knowledge of those conditions that may produce facial pain.
important to differentiate the pain of AO from pulpal pain, myofacial pain, and
from pain of trigeminal neuralgia. A common misdiagnosis is to consider the
pain from AO to be of pulpal origin, leading to unnecessary endodontic
Treatment of atypical odontalgia is similar
to that for other neuropathic conditions.3 Various drugs have been
used to treat AO, among them Gabapentin,29 Clonazepam,29
cocaine,29 monoamine oxidase (MAO) inhibitors,13 and
capsaicin has been used successfully to control neuropathic pain, and it has
been effective in most patients with atypical odontalgia.21 The
treatment of choice is a tricyclic antidepressant like Amitriptyline, alone or
in combination with a phenothiazine. The outcome is usually fair, with many
patients obtaining complete relief from pain.20 Treatment starts
with a low dose of 20 mg up to 75 mg of Amitriptyline that needs to be adjusted
according to two factors: pain control and adverse reactions. The dose is
titrated until an acceptable pain level is achieved, usually reaching up to 75
mg per day,24,30 but the appearance of side effects can prevent the
clinician from increasing the dosage. It is important to discuss the side
effects of Amitriptyline with the patient. Side effects may include dizziness,
drowsiness, headache, xerostomia, constipation, increased appetite, weight
gain, nausea, weakness, hypotension, arrhythmias, tachycardia, nervousness,
sedation, and diarrhea.31 It is also important to defer any invasive
dental procedures until after a definitive diagnosis of AO has been made.22
With regard to diagnosing this condition, Sir
William Osler’s maxim should always be remembered: “What you don’t know — you
won’t diagnose.”28 The condition of AO can be a challenging case to
diagnose and treat. It is important to have a thorough knowledge before
initiating any drug treatment. Sometimes it is prudent to refer the patient to
a pain specialist.
Neuropathic pain in the head and neck region
can be difficult to diagnose, and often the lack of diagnosis can lead to
unnecessary dental treatment and frustrating outcomes. Unfortunately, dentists
usually consider this diagnosis only after the failure of invasive treatment.16
The dentist and physician need to recognize AO and to remember that a proper
diagnosis can prevent unnecessary and irreversible dental treatment. n
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Proposed Diagnostic Criteria of Graff-Radford and Solberg.16
Idiopathic Toothache (atypical odontalgia).
in a tooth or a tooth site.
or almost continuous pain.
persisting more than four months.
sign of local or referred pain.
somatic nerve block.
*Dr. Koratkar is a general dentist in
private practice in the Twin Cities area. E-mail is firstname.lastname@example.org.
**Dr. Pedersen is the director of the Hibbing Dental Clinic of the University of Minnesota’s Department of
Primary Dental Care. E-mail is email@example.com.