Clinical characteristics and diagnosis of atypical odontalgia: Implications for dentists

BackgroundAtypical odontalgia (AO) is a poorly understood and commonly misdiagnosed condition for which patients often undergo multiple unsuccessful dental or surgical procedures. The authors conducted a study to determine the prevalence and describe the characteristics of patients with AO seen at the University of Southern California Orofacial Pain and Oral Medicine Center (USC OFP-OM Center), Los Angeles.MethodsThe authors conducted a retrospective record review from a database of more than 3,000 patient records from June 2003 to August 2007 to identify patients diagnosed with AO.ResultsThe authors identified 64 patients (44 women and 20 men) between the ages of 26 and 93 years as having a diagnosis of AO. Of those 64 patients, 71 percent initially consulted a dentist regarding their pain, and 79 percent had undergone dental treatment that failed to resolve the pain. The pain of 64 percent of the patients had no known cause.ConclusionsDentists, who often are the first health care providers to see patients with AO, must be aware of this condition and must follow the appropriate steps to determine its diagnosis.Clinical ImplicationsDentists and physicians should understand the implications and importance of early diagnosis of patients with AO and of referral to pain specialists for treatment.     

Atypical odontalgia--a diagnostic dilemma

Atypical odontalgia (AO) is a chronic orofacial pain condition of unclear pathophysiology, often presenting as toothache or pain at an extraction site. Idiopathic, psychogenic, vascular, and neuropathic causes have been proposed. In view of demonstrable somatosensory changes, and responses to management proposed for other forms of neuropathic pain, the best current evidence supports a neuropathic hypothesis. It is proposed that certain individuals with as-yet-undefined genetic vulnerability can develop AO when exposed to certain risk factors, including invasive dental treatment. The diagnosis and treatment of AO can be challenging, but can be aided by a multidisciplinary approach. Two cases of differing complexity are presented in this paper.     

Neuropathic orofacial pain

Neuropathic orofacial pain is a general term employed to describe a number of clinical syndromes, which may be spontaneous or triggered by local trauma or systemic disorders. Symptomatically these painful syndromes may be episodic or continuous and are often difficult to distinguish from dental pathology. In the present article, we review the diagnosis, pathophysiology and therapeutic approaches to trigeminal and glossopharyngeal neuralgias, orofacial pain associated with herpetic infection, persistent idiopathic facial pain (previously termed atypical facial pain), post-traumatic orofacial neuropathy and neuritis.     

Neuropathic orofacial pain part 1--prevalence and pathophysiology

Neuropathic pain is defined as "pain initiated or caused by a primary lesion or dysfunction in the nervous system". Neuropathic orofacial pain has previously been known as "atypical odontalgia" (AO) and "phantom tooth pain". The patient afflicted with neuropathic oral/orofacial pain may present to the dentist with a persistent, severe pain, yet there are no clearly identifiable clinical or radiographic abnormalities. Accordingly, multiple endodontic procedures may be instigated to remove the likely anatomical source of the pain, yet the pain persists. There have been few studies and limited patient numbers investigating the condition. Two retrospective studies revealed the incidence of persistent pain following endodontic treatment to be 3-6% and 5% of patients; one author with wide experience in assessing the condition estimated its prevalence at 125,000 individuals in the USA alone. In one study, 50% of neuropathic orofacial pain patients reported persistent pain specifically following endodontic treatment. Patients predisposed to the condition may include those suffering from recurrent cluster or migraine headaches. Neuropathic pain states include postherpetic neuralgia (shingles) and phantom limb/stump pain. The aberrant developmental neurobiology leading to this pain state is complex. Neuropathic pain serves no protective function, in contrast to physiological pain that warns of noxious stimuli likely to result in tissue damage. The relevant clinical features of neuropathic pain include: (i) precipitating factors such as trauma or disease (infection), and often a delay in onset after initial injury (days-months), (ii) typical complaints such as dysaesthesias (abnormal unpleasant sensations), pain that may include burning, and paroxysmal, lancinating or sharp qualities, and pain in an area of sensory deficit, (iii) on physical examination there may be hyperalgesia, allodynia and sympathetic hyperfunction, and (iv) the pathophysiology includes deafferentation, nerve sprouting, neuroma formation and sympathetic efferent activity.     

Diagnosis and treatment of atypical odontalgia: a review of the literature and two case reports

AIM: This report presents two cases diagnosed with atypical odontalgia (AO) and successfully treated with amitriptyline as well as providing a review of the current literature on the subject. RESULTS: The literature indicates the most important issue is an accurate differential diagnosis to distinguish between AO, pulpal pain, myofascial pain, and trigeminal neuralgia. CONCLUSION: Once the correct diagnosis is made the prognosis of AO is usually fair and the administration of tricyclic antidepressants often resolves symptoms. An effort should be made to avoid any unnecessary dental treatment that would only aggravate the problem.     

Phantom tooth pain: a diagnosis of exclusion

This case report addresses the difficult diagnosis of phantom tooth pain (PTP). This is a syndrome of persistent pain in the teeth and oral structures following pulp extirpation, extraction, or rarely, an inferior alveolar nerve block. The incidence of this often misdiagnosed condition is estimated to be 3% of the population undergoing pulp extirpation, and is similar to phantom limb pain. The diagnosis of PTP is discussed here as a diagnosis of exclusion, after numerous interventions. Various treatment modalities are outlined and the use of non-traditional pharmacological approaches for pain reduction are discussed.     

Atypical odontalgia--a form of neuropathic pain that emulates dental pain

In order for the neuropathic pain associated with AO to occur in the oral or facial area, a deafferentation process must be initiated as previously explained. Deafferentation happens when there is a trauma to tissues including, but not limited to, endodontic therapy, a surgical extraction or even a simple one, a deep scaling, an injurious dental injection, and even the placement of a crown. Thankfully, most patients heal uneventfully. Apparently a small percentage of patients have a genetic predisposition to deafferentation pain. In reviewing articles on this subject, there is often material about the inadvertent dental treatment of patients with AO. Many patients often have undergone numerous invasive procedures in an effort to ameliorate pain. It is not possible to read a research paper about AO without reading about the recurrent theme of either overtreatment or unnecessary treatment. Caution should be exercised when performing endodontic therapy solely for the relief of pain without objective need for such therapy. It is common for the AO patient to undergo many other irreversible dental treatments with no resolution of pain symptoms. When the dentist encounters a patient in pain for which there is no dental connection, he or she should strongly consider referring the patient to a facility or practitioner who has expertise in dealing with the non-dental source of dental pain.     

An update on pathophysiological mechanisms related to idiopathic oro‐facial pain conditions with implications for management

Chronic oro‐facial pain conditions such as persistent idiopathic facial pain (PIFP), atypical odontalgia (AO) and burning mouth syndrome (BMS), usually grouped together under the concept of idiopathic oro‐facial pain, remain a diagnostic and therapeutic challenge. Lack of understanding of the underlying pathophysiological mechanisms of these pain conditions is one of the important reasons behind the problems in diagnostic and management. During the last two decades, neurophysiological, psychophysical, brain imaging and neuropathological methods have been systematically applied to study the trigeminal system in idiopathic oro‐facial pain. The findings in these studies have provided evidence for neuropathic involvement in the pathophysiology of PIFP, AO and BMS. The present qualitative review is a joint effort of a group of oro‐facial pain specialists and researchers to appraise the literature on idiopathic oro‐facial pain with special focus on the currently available studies on their pathophysiological mechanisms. The implications of the findings of these studies for the clinical diagnosis and treatment of idiopathic oro‐facial pain conditions are discussed.     

Chronic orofacial pain: a clinical challenge

Most orofacial pain originates in the oral cavity and the surrounding structures. However, advances in the understanding of pain neurophysiology have shown that convergent afferent nociceptive transmissions from non-trigeminal, extraoral sources can enter the trigeminal system. This may confuse the diagnosis by presenting as (or contributing to) dental, sinus, temporomandibular and other head and neck pains. Incorrect diagnoses may lead to inappropriate and/or invasive procedures, creating further problems. Professor Richard Kroening (former Director of the UCLA Pain Management Center) repeatedly emphasised the maxim that "without correct diagnosis, there can be no prognosis". My own areas of special interest have included acute pain management (anaesthesia and conscious sedation) and chronic orofacial pain. I have seen many dental patients who have been referred to multidisciplinary pain management clinics, often after years of failed treatment attempts. More recent experience as a member of a hospital team evaluating long term ACC patients with many types of persistent pain problems again confirms the premise that accurate diagnosis is critical if management is to be successful.     

Chronic intraoral pain--assessment of diagnostic methods and prognosis

The overall goal of this thesis was to broaden our knowledge of chronic intraoral pain. The research questions were: What methods can be used to differentiate inflammatory, odontogenic tooth pain from pain that presents as toothache but is non-odontogenic in origin? What is the prognosis of chronic tooth pain of non-odontogenic origin, and which factors affect the prognosis? Atypical odontalgia (AO) is a relatively rare but severe and chronic pain condition affecting the dentoalveolar region. Recent research indicates that the origin is peripheral nerve damage: neuropathic pain. The condition presents as tooth pain and is challenging to dentists because it is difficult to distinguish from ordinary toothache due to inflammation or infection. AO is of interest to the pain community because it shares many characteristics with other chronic pain conditions, and pain perpetuation mechanisms are likely to be similar. An AO diagnosis is made after a comprehensive examination and assessment of patients' self-reported characteristics: the pain history. Traditional dental diagnostic methods do not appear to suffice, since many patients report repeated care-seeking and numerous treatment efforts with little or no pain relief. Developing methods that are useful in the clinical setting is a prerequisite for a correct diagnosis and adequate treatment decisions. Quantitative sensory testing (QST) is used to assess sensory function on skin when nerve damage or disease is suspected. A variety of stimuli has been used to examine the perception of, for example, touch, temperature (painful and non-painful), vibration, pinprick pain, and pressure pain. To detect sensory abnormalities and nerve damage in the oral cavity, the same methods may be possible to use. Study I examined properties of thermal thresholds in and around the mouth in 30 pain-free subjects: the influence of measurement location and stimulation area size on threshold levels, and time variability of thresholds. Thresholds for cold, warmth and painful heat were measured in four intraoral and two extraoral sites. Measurements were repeated 3 times over 6 weeks, using four sizes of stimulation area (0.125-0.81 cm2). The threshold levels were highly dependent on location but less dependent on measuring probe size and time variability was small, and this knowledge is important for the interpretation of QST results. Study II applied a recently developed standardized QST examination protocol (intended for use on skin) inside the oral cavity. Two trained examiners evaluated 21 pain-free subjects on three occasions over 1-3 weeks, at four sites-three intraoral and one extraoral. Most tests had acceptable reliability and the original test instruments and techniques could be applied intraorally with only minor adjustments. Study III examined the value of cone-beam computed tomography (CBCT) in pain investigations. Twenty patients with AO and 5 with symptomatic apical periodontitis (inflammatory tooth pain) participated. The results indicate that when AO is suspected, addition of CBCT can improve the diagnostic certainty compared to sole use of periapical and panoramic radiographs, especially because of the superior ability of CBCT to exclude inflammation as the pain cause. Study IV assessed the long-term prognosis of AO, and analyzed potential outcome predictors. A comprehensive questionnaire including validated and reliable instruments was used to gather data on patient and pain characteristics and pain consequences from 37 patients in 2002 and 2009. Thirty-five percent of the patients reported substantial overall improvement at follow-up, but almost all still had pain of some degree after many years. The initial high level of emotional distress was unchanged. Low baseline pain intensity predicted improvement over time.     

Recognition and management of headache

Pain of all types continues to cause substantial burdens to society because of high health care costs and decreased productivity. Dental patients may present with facial pain (often subjectively defined as pain below the ala-tragus line) associated with headache (subjectively defined as pain above the ala-tragus line), both of which are often poorly diagnosed and treated. People with ongoing pain lasting for more than 3-6 months (chronic pain) may experience multiple types of pains in the head and neck region, including headache, facial pain or even global head pain (pain throughout the head, from the neck up). Some pain problems do not follow strict anatomic boundaries, and the pain may spread into adjacent regions, which complicates diagnosis. A better understanding and appreciation of headaches and facial pain can lead to improved outcomes and better overall management. This article reviews frequently occurring headache disorders that should be considered in the differential diagnosis of pain seen in the dental office.     

Atypical odontalgia - pathophysiology and clinical management.

Atypical odontalgia (AO) is a chronic form of dental pain without signs of pathology. Several hypotheses have been put forward regarding the pathophysiology. AO has been proposed to be psychogenic, vascular, neuropathic or idiopathic. The scientific evidence supporting or rejecting these hypotheses are reviewed in this paper. At this time, the best supported hypothesis is that AO is a neuropathic pain condition. Relevant differential diagnoses, such as odontogenic pain, sinusitis, trigeminal neuralgia among others, are presented and the evidence regarding possible management strategies is reviewed. A treatment algorithm for AO is proposed based on the rather scarce scientific evidence available and inspired by a similar treatment algorithm for peripheral neuropathic pain. The proposed strategy involves an interdisciplinary approach including patient education, psychological counselling, topical and systemic medication and, importantly, avoidance of invasive treatments like surgery and endodontics. Two illustrative cases are presented.     

Identification of patients at risk for unnecessary or excessive TMJ surgery

Musculoskeletal pain in the head and neck may be associated with a variety of psychological and psychiatric conditions. Therefore, patients with persistent temporomandibular (TMJ) and masticatory muscle complaints must also be evaluated for affective disorders. Identification of patients at risk for unnecessary or excessive TMJ surgery is enhanced when the surgeon is aware of a pattern of persistent pain and illness insistence that characterizes these patients. This article presents a list of characteristics that may identify a patient with an undiagnosed affective disorder who may be exposed to unnecessary treatment.     

Atypical odontalgia – pathophysiology and clinical management

Summary  Atypical odontalgia (AO) is a chronic form of dental pain without signs of pathology. Several hypotheses have been put forward regarding the pathophysiology. AO has been proposed to be psychogenic, vascular, neuropathic or idiopathic. The scientific evidence supporting or rejecting these hypotheses are reviewed in this paper. At this time, the best supported hypothesis is that AO is a neuropathic pain condition. Relevant differential diagnoses, such as odontogenic pain, sinusitis, trigeminal neuralgia among others, are presented and the evidence regarding possible management strategies is reviewed. A treatment algorithm for AO is proposed based on the rather scarce scientific evidence available and inspired by a similar treatment algorithm for peripheral neuropathic pain. The proposed strategy involves an interdisciplinary approach including patient education, psychological counselling, topical and systemic medication and, importantly, avoidance of invasive treatments like surgery and endodontics. Two illustrative cases are presented.     

Toothache of cardiac origin

Pain referred to the orofacial structures can sometimes be a diagnostic challenge for the clinician. In some instances, a patient may complain of tooth pain that is completely unrelated to any dental source. This poses a diagnostic and therapeutic problem for the dentist. Cardiac pain most commonly radiates to the left arm, shoulder, neck, and face. In rare instances, angina pectoris may present as dental pain. When this occurs, an improper diagnosis frequently leads to unnecessary dental treatment or, more significantly, a delay of proper treatment. This delay may result in the patient experiencing an acute myocardial infarction. It is the dentist's responsibility to establish a proper diagnosis so that the treatment will be directed toward the source of pain and not to the site of pain. This article reviews the literature concerning referred pain of cardiac origin and presents a case report of toothache of cardiac origin.     

Atypical odontalgia: a systematic review following the evidence-based principles of dentistry

Atypical odontalgia (AO) is a severe and persistent pain involving controversial pathophysiological mechanisms and clinical management. Presented here is a systematic review of the literature on AO, using the SORT criteria (Strength of Recommendation Taxonomy) to assess the level of evidence and the quality of randomized clinical trials (RCT). A total of 54 articles were obtained of which 34 belonged to level 3 evidence, 17 to level 2, and 3 to level 1. Of these, only 8 RCT had an average quality of four points. The main finding of this systematic review is that only a few studies have systematically evaluated AO. It also determines a strength recommendation of level B to the theory of neuropathic origin of pain in AO and strength of recommendation level C for the pharmacological management of this condition. The aim of this study was to carry out a systematic review of the published literature on AO in order to determine the physiopathology and treatment based on the level of scientific evidence and following the evidence-based principles of dentistry.     

Treatment of common orofacial conditions

The conditions discussed in this article are those most likely to cause a patient to seek emergency care, primarily for pain. All the characteristics given for the conditions to aid in the diagnosis do not necessarily need to be present and other characteristics not mentioned may in fact be present. A complete differential diagnosis, especially of more obscure lesions, was also not attempted. An attempt was made to provide the practitioner with enough information to develop a working diagnosis from which to alleviate the patient's discomfort. A definitive diagnosis may not be available in an emergency setting. However, it must be emphasized that the final responsibility of the dentist is to make a definitive diagnosis at a later time if one cannot be made when emergency treatment is sought. Alleviating pain without dealing with the underlying cause may be more detrimental to the patient's health in the long run, as palliative therapy may mask a more severe condition.     

Orofacial pain in cancer: part II--clinical perspectives and management

Cancer-associated pain is extremely common and is associated with significant physical and psychological suffering. Unfortunately, pain associated with cancer or its treatment is frequently under-treated, probably due to several factors, including phobia of opioids, under-reporting by patients, and under-diagnosis by healthcare workers. The most common etiology of cancer pain is local tumor invasion (primary or metastatic), involving inflammatory and neuropathic mechanisms; these have been reviewed in Part I. As malignant disease advances, pain usually becomes more frequent and more intense. Additional expressions of orofacial cancer pain include distant tumor effects, involving paraneoplastic mechanisms. Pain secondary to cancer therapy varies with the treatment modalities used: Chemo-radiotherapy protocols are typically associated with painful mucositis and neurotoxicity. Surgical therapies often result in nerve and tissue damage, leading, in the long term, to myofascial and neuropathic pain syndromes. In the present article, we review the clinical presentation of cancer-associated orofacial pain at various stages: initial diagnosis, during therapy (chemo-, radiotherapy, surgery), and in the post-therapy period. As a presenting symptom of orofacial cancer, pain is often of low intensity and diagnostically unreliable. Diagnosis, treatment, and prevention of pain in cancer require knowledge of the presenting characteristics, factors, and mechanisms involved.     

Treatment of injuries to the inferior alveolar nerve after endodontic procedures

Overextension of filling material into the mandibular canal after root treatment in the lower jaw is a rare but serious complication. Mechanical compression, chemical neurotoxicity and local infection may cause irreversible nerve damage. A report on 11 patients with neurological complaints of the inferior alveolar nerve after endodontic treatment is summarised. The neurological findings are dominated by hypaesthesia and dysaesthesia. Half of the patients reported pain. Hyperaesthesia is found much more rarely. Nearly all the patients had a combination of one or more symptoms. Initial X-rays showed root filling material in the area of the mandibular canal. Nine cases were treated with apicectomy and decompression of the nerve; in two cases, extraction of the tooth was necessary. Only one patient reported persistent pain after surgery. If neurological complaints appear after root filling in the lower jaw, a nerve injury due to root filling material should be ruled out. In cases of overfilling, immediate apicectomy and decompression of the nerve with conservation of the tooth is often the treatment of choice; the tooth may be preserved and the best chance of avoiding permanent nerve damage is provided.