[Downloaded free from http://www.indianjpain.org on Saturday, March 05, 2016, IP: 117.194.98.119] Review Article Phantom tooth pain: The atypical facial pain Subrata Ray, Parvin Banu1, Subrata Goswami2, Ramapati Sanyal2, Basu SM2 Department of Anaesthesia and Pain, KPC Medical College and Hospital, 1Department of Anaesthesia and Critical Care, CNMC and Hospital, 2Department of Pain Management, ESI Institute of Pain Management, Kolkata, West Bengal, India ABSTRACT Chronic pain is more prevalent in the head and neck region than other parts of the body. Almost one-third of patients attending a facial pain clinic have history of undergoing some dental procedures often without success. Literature review reveals that atypical odontalgia, atypical facial pain or if teeth have been extracted phantom tooth pain are used to describe a common pain syndrome. At present, chronic pain disorders are diagnosed mainly on the basis of clinical signs and symptoms, since the mechanism underlying the pathophysiology is not well understood. Many diagnostic criteria for atypical facial pain has been proposed without much benefi t however, it remains a diagnosis of exclusion after ruling out all other pathologies of the head and neck. Clinically, phantom tooth pain is similar in many essential characteristics to deafferentation pain syndrome. In the absence of controlled clinical trials specifi cally directed to phantom tooth pain, treatment should be guided by standards used for other neuropathic pain disorders. Key words: Chronic, neuropathic, pain, phantom tooth Introduction pain. Atypical facial pain was fi rst coined by Frazier and Russell to diff erentiate it from trigeminal neuralgia.[4] It was Chronic pain is more prevalent in the head and neck region also included in the classifi cation system of international [1] than other parts of the body. Lipton et al. described that headache society (2004), and presented in the category of an estimated 22% of the general population experience facial pain not fulfi lling other criteria.[5] One group applied orofacial pain given over a period of 6 months.[2] Almost ontological principle for classifying orofacial pain disorder, one-third of patients attending a facial pain clinic have using the descriptive name, persistent dentoalveolar pain history of undergoing some dental procedures often (PDAP) syndrome, and produced initial diagnostic criteria.[6] without success. If no attributing factors such as infection, In an attempt to avoid further confusion, the Association inflammation or other pathology detected, then the for the Study of Pain (IASP) discontinued to list atypical diff erential diagnoses should include phantom tooth pain. facial pain in their classifi cation of chronic pain. Recently, Phantom tooth pain has many common features of other phantom pain disorders. IASP also advocated for the similar broader term to defi ne phantom tooth pain or atypical odontalgia, as mentioned The aim of this article is to review current knowledge about this disorder which has been validated extensively, Address for correspondence: [3] Dr. Subrata Goswami, yet reported rarely. 3A Maharani Swarnamoyee Road, Kolkata - 700 009, West Bengal, India. Literature review reveals that diff erent terms have been used E-mail: [email protected] to describe this syndrome, e.g., atypical odontalgia, atypical facial pain, or if teeth have been extracted phantom tooth This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Access this article online License, which allows others to remix, tweak, and build upon the Quick Response Code: work non-commercially, as long as the author is credited and the Website: new creations are licensed under the identical terms. www.indianjpain.org For reprints contact: [email protected] DOI: How to cite this article: Ray S, Banu P, Goswami S, Sanyal R, 10.4103/0970-5333.165817 Basu SM. Phantom tooth pain: The atypical facial pain. Indian J Pain 2015;29:124-6. 124 © 2015 Indian Journal of Pain | Published by Wolters Kluwer - Medknow [Downloaded free from http://www.indianjpain.org on Saturday, March 05, 2016, IP: 117.194.98.119] Ray, et al.: Phantom tooth pain in their bulletin of global year against orofacial pain (2013) Other attributing mechanism involves sensitization that following a recent consensus exercise involving clinical of pain fi bers, sprouting of adjacent aff erent fi bers, experts and methodologists, the entity has been termed sympathetic-sensory aff erent coupling, diminished or persistent PDAP disorder, and diagnostic criteria have been loss of inhibitory mechanism, and phenotypic switching proposed.[7] Although the criteria were expert-derived and of aff erent neurons.[14] Phenotypical changes in primary not evidence-based, and as such were less than ideal.[8] aff erents and dorsal horn neurons have revealed that after nerve injury long term changes may occur in gene Diagnosis expression such as changes in ionic channel proteins, neurotransmitters, and neurotrophins.[16] Although The majority of time this problem is misdiagnosed by a sympathetic axons sprouting into dorsal root ganglion dentist, which can lead to unnecessary interventions with where they form baskets around sensory neuron has not no resolution of the pain symptoms. Patient in the dental been shown in the trigeminal region yet.[17] The episodic environment are more likely to be considered to have neuropathic pain presents as a period of remission of dental pain as opposed to patient referred to a physician. symptoms in contrast to continuous neuropathic pain, Myofascial, neurovascular, sinus, and cardiac structures which is unremitting pain condition.[18] The inconclusive can all be the source of referred dental pain, frustrating the data assessing psychological factors in relation to diagnostic eff orts of the general practitioner.[9] At present, persistent dental pain prevents any conclusion regarding chronic pain disorders are diagnosed mainly on the basis their role in the development of this chronic pain of clinical signs and symptoms, since the mechanism disorder.[8] underlying the pathophysiology is not well understood. Unlike acute pain, persistent pain has no biological Treatment advantage. Many diagnostic criteria for atypical facial pain has been proposed without much benefi t however, it In the absence of controlled clinical trials specifi cally remains a diagnosis of exclusion after ruling out all other directed to phantom tooth pain, treatment should be pathologies of the head and neck.[10] guided by standards used for other neuropathic pain disorders.[10] Furthermore, experts agree that earlier Pathophysiology recognition and initiation of therapy is more benefi cial than delayed diagnosis and treatment. Based on available The pathophysiology of phantom tooth pain or evidence from other neuropathic pain conditions, atypical odontalgia is poorly understood. One study tricyclic antidepressants (TCAs) or gabapentin would be calculated odds ratios and it found that extended the fi rst drug indicated.[19] Undesirable side eff ects require duration of preoperative pain, presence of other that TCAs be titrated to the lowest clinically eff ective chronic pain problems, female gender, and a history dose and discontinued if pain abates.[20] Topical capsaicin of painful treatment in the orofacial region are application to the painful tissue has also been investigated statistically signifi cant risk factors for persistent pain for atypical odontalgia.[21] Nonsteroidal anti-infl ammatory following root canal therapy.[11] Marbach hypothesized drugs are either ineff ective or produce a temporary result. that atypical odontalgia was of similar etiology to Several sets of observational data recommend against phantom limb pain.[12] Clinically, phantom tooth repeated interventional procedures.[8] Repeated surgical pain is similar in many essential characteristics to injury, unless there is a specifi c indication may worsen deaff erentation pain syndrome. A limitation to this the situation. Additional treatment options proposed taxonomy is the lack of defi nitive information with include transcutaneous electrical nerve stimulation, respect to the pathophysiology of deaff erentation pain sympathetic nerve blocks, psychotherapy, and behavioral in the trigeminal nerve.[13] The cortical reorganization approaches.[22] hypothesis proposes that after deaff erentation injury, organization and activity of central and peripheral Conclusion nerves can change. This can result in chronic pain symptoms,[14] which is basically neuropathic in nature. About one-third of patient attending facial pain clinic Epidemiologic information indicates that 3-6% of have history of undergoing some dental procedure. patient develop atypical odontalgia after endodontic Phantom tooth pain or atypical odontalgia has many therapy.[15] After root canal therapy, persistent pain characteristics of neuropathic pain syndrome. Diagnosis was reported in 3-13% of cases.[11] Neuroma secondary is challenging and based on clinical signs and symptoms. to nerve injury is thought to result in such pain.[12] Early initiation of treatment is benefi cial. Treatment Indian Journal of Pain | September-December 2015 | Vol 29 | Issue 3 125 [Downloaded free from http://www.indianjpain.org on Saturday, March 05, 2016, IP: 117.194.98.119] Ray, et al.: Phantom tooth pain should be based on other neuropathic pain disorders. 9. DuPont JS Jr. Neuritic toothache. Gen Dent 2001;49:178-81. Further surgical injury without specifi c