Indian Journal of Dental Research

: 2012  |  Volume : 23  |  Issue : 4  |  Page : 529--536

Temporomandibular disorders and functional somatic syndromes: Deliberations for the dentist

S Suma, B Veerendra Kumar 
 Department of Oral and Maxillofacial Pathology, DA Pandu Memorial RV Dental College and Hospital, No. CA 37, 24th Main, JP Nagar I Phase, Bangalore, Karnataka, India

Correspondence Address:
S Suma
Department of Oral and Maxillofacial Pathology, DA Pandu Memorial RV Dental College and Hospital, No. CA 37, 24th Main, JP Nagar I Phase, Bangalore, Karnataka


Temporomandibular disorder (TMD) is an umbrella term for a collection of disorders affecting the temporomandibular joint (TMJ) and associated tissues. TMD is not a rare pathology for the dentist. The most common presenting symptom is pain, which causes the patient seek immediate treatment. Management is dictated by the cause. The most «SQ»famed«SQ» causes include trauma, inflammation, aging, parafunctional habits, infections, neoplasms, and stress; and these are always considered in the differential diagnosis of TMJ pain. There are some less «SQ»famed«SQ» causes of TMD, which are characterized by increased pain sensitivity due to psychosocial factors; these include myofascial pain syndrome and functional somatic syndromes (FSS) such as fibromyalgia and chronic fatigue syndrome. They present with chronic pain, fatigue, disability, and impairment in ability to perform daily activities. A non-systematic search in the English literature revealed numerous studies describing the occurrence of TMD in these conditions, along with few other oral manifestations. TMD has been even considered to be a part of the FSS by some. In these patients, TMD remains a recurring problem, and adequate management cannot be achieved by traditional treatment protocols. Awareness of these conditions, with correct diagnosis and modification of management protocols accordingly, may resolve this problem.

How to cite this article:
Suma S, Veerendra Kumar B. Temporomandibular disorders and functional somatic syndromes: Deliberations for the dentist.Indian J Dent Res 2012;23:529-536

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Suma S, Veerendra Kumar B. Temporomandibular disorders and functional somatic syndromes: Deliberations for the dentist. Indian J Dent Res [serial online] 2012 [cited 2021 Jul 26 ];23:529-536
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Full Text

Temporomandibular disorders (TMD) are a major cause of pain in the temporomandibular joint (TMJ) and, thus, not a rare pathology for the dentist. A host of causes have been implicated in TMD, and management is dictated by the specific cause. In some patients, TMD remains a recurring problem and adequate management is difficult to achieve. Cognizance of all the causes, with correct diagnosis and modification of management protocols accordingly, may resolve this problem.

The term 'functional somatic syndromes' (FSS) has been applied to several related syndromes that are characterized more by symptoms, suffering, and disability than by any consistently demonstrable tissue abnormality. [1] Psychological factors are a major component of FSS. There is ongoing debate as to whether the FSS comprise one entity or many. [2],[3],[4]

This paper aims at reviewing the relationship between TMD and FSS in order to create awareness among dentists regarding fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome as etiologies of TMD. We present an overview of these conditions with the intention of alerting the clinician to consider these conditions during the diagnosis and management of patients with TMD.

A non-systematic search of the English literature using the key words 'temporomandibular disorders,' 'temporomandibular joint syndrome,' 'functional somatic syndromes,' 'fibromyalgia,' 'chronic fatigue syndrome,' 'myofascial pain syndrome,' separately and in different combinations, was performed for the collection of data.

 Temporomandibular Disorders

TMD or temporomandibular joint syndrome (TMJS) is a term that embraces a number of clinical problems that involve the masticatory muscles, the TMJ, and the associated structures. [5] It was earlier famous as the myofascial pain-dysfunction syndrome. [6] Though a staggering 60%-70% of the general population has at least one sign of TMD, only 5% actually seek treatment! [7] In fact, it is the second most common cause of facial pain, [6] occurring mainly in young and middle-aged women. [5],[6],[7],[8]

The classical symptoms of TMD are orofacial pain, muscle tenderness, joint noises, and restricted jaw function [7] [Table 1]. Pain can occur in the TMJ region (described by the patient as pain in front of the ear) or can be referred to the temple, neck, and shoulders. The muscles of mastication are tender on palpation and there may be pain during chewing, yawning, or clenching of teeth. Clicking of the TMJ or crepitus within the joint can be elicited on examination. There may be limitation in jaw opening or the jaw may deviate to one side on opening of the mouth. [6],[7],[8],[9],[10] Other symptoms of TMD include headaches [6],[7],[8],9] (the most common type being migraine [11],[12] ), dizziness, nausea, blurred vision, tinnitus, and idiopathic pruritus. Increased stress levels [10],[13] and negative impact on the quality of life have been noted, [10] with these effects being directly proportional to the duration of the symptoms. [14] {Table 1}

The varying clinical presentations, varying degree of morbidity, and varying responses to management of TMD patients have further confounded the existing uncertainty regarding the etiology of TMD. Clark [15] and Bhat [16] have reviewed the etiology of TMD in detail. Our literature search revealed the following etiological concepts [5],[15],[16]:

The early theories: These were purely mechanical concepts and did not consider biologic variations. The traditional treatment protocol for TMD was based on these concepts. Costen (1934), an otolaryngologist, brought TMD under the purview of dentistry by proposing occlusal prematurities and resultant faulty condylar positioning as the basic etiology of TMD. [5],[16] Since then, many studies have reviewed the role of occlusal factors in TMD (McNamara et al.[17] ) and found no strong causal relationship between the two. Trauma (Zarb and Speck, Reade), [5],[16] osteoarthritis (Stengenga), [16] chronic myospasm (Travell and Rinzler), [16] neuromuscular incoordination due to occlusal interferences (Ramfjord), [16] and psychological factors (Schwartz and Laskin) [5],[16] have been described as the sole cause of TMD by various authors. Gradually, the unifactorial concept lost popularity due to the accumulation of evidence implicating other etiological agents in TMD.Current concept: Currently it is believed that TMD has a multifactorial etiology. Thus biologic variations are also taken into consideration. This concept explains the differences between the young and old and between men and women in the frequency and presentations of TMD. The multifactorial concept recognizes the presence of predisposing, initiating, and perpetuating factors [16] [Table 2].{Table 2}

The 'biopsychosocial model' proposed by Dworkin et al. (1992), [15],[16] is presently the most accepted etiological model for TMD. As the name suggests, this concept takes into consideration biological, psychological, and social factors. The TMD patient has to deal with the biological problem (active pain pathways); psychological problems (emotional and behavioral factors, as both cause and consequence); and social problems (interpersonal relationships). This concept has brought about a major change in the approach towards the management of TMD and is the basis for the research diagnostic criteria for TMD. A practical rehabilitation and management of TMD is aimed at, rather than an unachievable permanent cure. [5] Parker [18] has proposed a dynamic etiologic model wherein an imbalance between destructive and adaptive factors in the masticatory system is the cause of TMD.

Two systems are used to categorize TMD [9] : The research diagnostic criteria (a very comprehensive classification by Dworkin and LeResche, 1992) and the American Academy of Orofacial Pain classification (more useful in the clinical setting, [Table 3]).{Table 3}

TMD is diagnosed by thorough clinical examination, imaging techniques (MRI preferred over CT scan), ultrasonography, and a detailed psychosocial and psychiatric assessment. [7],[9]

Owing to its multifactorial etiology and the variety of symptoms, the management of TMD requires a customized approach to each patient. Patient education, physiotherapy, stress management, occlusal corrections, pharmacological therapy, joint manipulation, and surgery are the different modalities of management that are used−alone or in various combinations−based on the cause(s) identified. [5],[6],[7],[15]

 Functional Somatic Syndromes

The term functional somatic syndrome has been applied to several related syndromes that are characterized more by symptoms, suffering, and disability than by objective structural/functional abnormalities. FSS mainly affect females, and the onset is usually under 30 years of age. The etiopathogenesis of FSS is still unknown [1],[2] and therefore the classification of FSS is still imperfect, the diagnosis complicated and, consequently, the treatment challenging. These syndromes include multiple chemical sensitivity, the sick building syndrome, repetitive strain injury (RSI), the side effects of silicone breast implants, the Gulf War syndrome, chronic whiplash injury, chronic fatigue syndrome (CFS), irritable bowel syndrome, and fibromyalgia. [1] Of these, fibromyalgia, [2],[19],[20],[21],[22],[23],[24],[25],[26],[27] myofascial pain syndrome (MPS), [2],[28] and CFS [2],[26],[29],[30],[31] have been associated with TMD and a few other oral manifestations and hence are of significance to the dentist.

Fibromyalgia is a syndrome characterized by chronic widespread musculoskeletal pain, stiffness, nonrestorative sleep, fatigue, cognitive dysfunction (famous as the 'fibro fog') and, consequently, impaired daily activities. The diagnostic feature is the presence of 'tender points' in the muscle and connective tissue in all four quadrants of the body [Figure 1]. [19],[26],[32],[33] However, it is not a musculoskeletal disorder per se. [34] There may be coexistence of other nonspecific symptoms and clinical conditions as well [2],[19],[26],[27],[32],[33] [Table 4]. Diagnosis is made by the fibromyalgia classification criteria given by the American College of Rheumatology in 1990 [19] [Table 5]. The cause is still uncertain. Abnormalities in the hypothalamic-pituitary-adrenal axis have been identified, as well as increased levels of substance P, serotonin, and growth hormone. [2],[19],[25],[33],[35],[36] {Figure 1}{Table 4}{Table 5}

Chronic fatigue syndrome is a disabling illness, with patients complaining of profound fatigue of at least 6 months duration as well as other rheumatological, infectious, and neuropsychiatric symptoms. [30],[33] Fibromyalgia and CFS have many symptoms in common, but fatigue is the predominant symptom in CFS, whereas pain predominates in fibromyalgia. The underlying pathophysiology is uncertain though evidence points towards central nervous system dysfunction. [30],[36] CFS has been reviewed in detail by Afari and Buchwald in 2003. [30] Diagnosis of CFS is made by the criteria given by the Center for Disease Control in 1988; [29] these criteria are as follows:

Severe chronic fatigue of 6 months or longer duration, with other known medical conditions excluded by clinical diagnosisConcurrently, four or more of the following symptoms:

Impaired short-term memory or concentrationSore throatTender lymph nodesMuscle painMulti-joint pain without swelling or rednessHeadaches of a new type, pattern, or severityUnrefreshing sleepPostexertional malaise lasting more than 24 hours

The symptoms must have persisted or recurred during 6 or more consecutive months of illness and must not have predated the fatigue.

The diagnostic clues to CFS have been discussed by Harvery and Wessely and an etiological model proposed. [37]

Myofascial pain syndrome (MPS) is a noninflammatory musculoskeletal disorder that manifests as musculoskeletal pain, limited mobility, weakness, and referred pain. [32],[33],[38] It is not to be confused with the 'myofascial pain-dysfunction syndrome'. MPS commonly occurs in the maxillofacial area. [28] The diagnostic feature is the presence of taut bands (linear band-like hardness) in one or more muscles. These are precise 'trigger points' that when palpated give rise to intense pain at the site as well as referred pain to a distal site. MPS is not included in the list of FSS by some authors [1] since it is a muscle disorder caused due to local metabolic stress leading to an energy crisis in the muscle and tautness. However, it is discussed here in this article since it is the main differential diagnosis for fibromyalgia and CFS. MPS is more localized than fibromyalgia. The differences between the two have been discussed by Chandola et al.[32] and others. [34],[39],[40],[41]

The FSS have many symptoms in common [Figure 2] and [Figure 3]. All of them coexist with psychosocial disorders [2],[3] and are associated with cumulative lifetime stress; [41] in addition, a central nervous system dysfunction has been found in most of them. [2],[3] Overlapping conditions, with more than one FSS occurring together in a patient, have been described, particularly combinations of fibromyalgia, CFS, MPS, and psychiatric disorders. [1],[2],[19],[30],[32],[42],[43] Literature review showed few major differences between fibromyalgia, CFS, and MPS. [21],[22],[26],[32],[33],[39],[40] [Table 6]. Many scholars disbelieve the existence of specific somatic syndromes and say that the different syndromes have been categorized separately because health professionals of different specialties focus only on those symptoms that are relevant to their discipline. For example, rheumatologists give importance to muscle pain and favor the diagnosis of fibromyalgia, gastroenterologists concentrate on the abdominal symptoms and diagnose irritable bowel syndrome, physicians concentrate on fatigue and infectious symptoms and hence their diagnosis is chronic fatigue syndrome. However, other authors consider each syndrome to be different. Hence, they are currently considered as a group of somatic manifestations that are essentially different expressions of the same abnormality. [2],[3],[4],[42] {Figure 2}{Figure 3}{Table 6}

The diagnosis of FSS is complex due to many reasons: for example, many health professionals do not believe in the existence of these entities, diagnosis is by symptoms rather than signs, no reproducible investigations exist, and there is the possibility of overlapping conditions. Ruling out the presence of other medical conditions is important. The treatment of FSS is customized for each patient; is multimodal (including pharmacological and nonpharmacological methods); and is multidisciplinary, with the physician, rheumatologist, neurologist, neuropsychiatrist, psychiatrist, physical therapist, and TMJ specialist/dentist acting as a team [19],[23],[28],[30],[32] [Figure 4].{Figure 4}

 Relationship Between Temporomandibular Disorders and Functional Somatic Syndromes

During our literature search we found that TMD was mentioned in association with FSS in most of the scholarly articles pertaining to FSS. [2],[19],[20],[21],[23],[26],[27],[29],[30],[36],[37],[40],[41] Curiously, however, only a few articles on TMD mentioned the association with FSS. [5],[10] The reason could be that most FSS have TMD as one of the clinical manifestations, but only a small percentage of TMD patients have FSS. Studies have shown that at least 75% patients with fibromyalgia have TMD, and only 10%-18% of TMD patients have fibromyalgia. [9],[26],[44] Nevertheless, the association is significant enough to be considered in the dental clinical setting. After scrutinizing the literature data, two possible relationships between TMD and FSS were found:

FSS is one of the factors in the etiology of TMDTMD belongs to the group of FSSFSS is one of the etiological factors in TMD [19],[24] : Many studies have focused on the presence of TMD symptoms in various FSS. Most of the attention has been on fibromyalgia, and a strong relationship has been found between fibromyalgia and TMD [2],[19],[20],[21],[22],[23],[24],[25] [Table 7]. Though TMD and fibromyalgia share many symptoms, TMD is a localized disorder unlike fibromyalgia, which is generalized; fibromyalgia manifests with more tender points and causes more distress than TMD. [20] The presence of TMD has also been reported in other FSS such as CFS, MPS, irritable bowel syndrome, premenstrual syndrome, stress syndrome, tension headaches, nonulcer dyspepsia, interstitial cystitis, atypical cardiac pain, atypical facial pain, glomus syndrome, and hyperventilation syndrome. [2],[45] Central nervous system dysfunction and the resultant alteration in pain perception might be the cause for the TMD in these patients. [5],[19] {Table 7}

In the etiology of TMD, FSS can be included under the category of myofascial pain (internal derangement of TMD is unlikely to be related to FSS [19] ). It is important to recognize TMD that is present along with a developing or an underlying and undiagnosed fibromyalgia. In such cases, routine management protocols may not be successful.TMD belongs to the group of FSS: Fantoni et al.[2] advocate the inclusion of TMD in the group of FSS due to the following evidence in literature: TMD share many symptoms with FSS, including chronic pain, headaches, dizziness, nausea, and unrefreshing sleep. [2],[19],[26],[36] In particular, TMD are strongly associated with psychosocial disturbances (80% of cases)-particularly depression, stress, and anxiety-similar to FSS. [2],[5],[9],[10],[43],[46] The prevalence of mood disorders in TMD has been found to be 43% in Asians and 30%-60% in Caucasians. Both disorders have a multifactorial etiology and require a multidisciplinary management approach. [2] Therefore, including TMD in the group of FSS could result in superior assessment, diagnosis, and management of TMD patients.

 Deliberations for the Dentist

Although only a few TMD patients also have FSS, the dentist can participate in the diagnosis and management of these conditions in the following ways:

Through awareness of these functional somatic syndromes, especially fibromyalgia, CFS, and MPS: It is important for the dentist to be aware of these conditions as a cause of TMD. Myofascial pain syndrome involves the TMJ commonly. [28] Other orofacial manifestations, e.g., Sjögren syndrome, glossodynia, dysgeusia, xerostomia (due to medications), and nonspecific oral ulcers, have been reported in fibromyalgia and CFS. [19],[20],[29],[31]Through participation in the diagnosis of FSS: The dentist may be the first to detect the presence of these conditions. A detailed history might point toward FSS [Figure 5]. The dentist must refer such cases to a physician for confirmation of the diagnosis and typing of the FSS, since the differential diagnoses for FSS include medical disorders such as multiple sclerosis, Lyme disease, thyroid disorders, bipolar disorder, and vitamin deficiencies. [33] {Figure 5}Through participation in the management of TMD with FSS: The dentist can be an active participant in the management of TMD patients who also have FSS. In such cases, a multidisciplinary approach is required for satisfactory therapeutic results since management of only the TMD by the dentist will definitely result in a failed treatment.

 Special Considerations in the Dental Office

TMD patients with FSS demonstrate reduced range of jaw movement, decreased maximum voluntary mouth opening, more jaw tiredness, greater difficulty in mouth opening, more pain during jaw function, more number of tender points, and a lower pain threshold than individuals with TMD alone. [18],[21],[22],[47] Their quality of life is restricted. Therefore, certain special considerations during the treatment of these patients (both treatment of TMD as well as routine dental treatment) can make a world of difference to them. Balasubramaniam et al.[19] have enumerated certain modifications in dental treatment procedures for patients with TMD. The same would be applicable for other FSS also. Shorter dental appointments, adequate support to the jaw during treatment, keeping in mind the possibility of drug interactions before prescribing any medications (these patients are usually on antidepressant medications) are some of the considerations.


There is evidence of a significant relationship between TMD and FSS such as fibromyalgia, CFS, and MPS. The debate is regarding whether to consider FSS as a cause of TMD or include TMD under the umbrella of FSS. Whatever the relationship, the dentist should consider these conditions during the diagnosis and management of TMD. At any indication of the presence of or development of FSS in a TMD patient, the dentist should refer the patient to a physician for exclusion of other medical conditions, definitive diagnosis, psychological assessment, typing of FSS, and treatment planning. TMD management in these patients cannot be achieved by the traditional methods of TMD treatment alone and, as such, certain modifications are required for these patients even during routine dental treatment. A multidisciplinary approach for the management of the underlying FSS is required and the dentist should be an active participant in this team.


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