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MYOFASCIAL FACE PAIN
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ARTICLE 1
C O V E R S T O R Y
MYOFASCIAL FACE PAIN
Clinical Characteristics of Those With Regional vs. Widespread Pain KAREN G. RAPHAEL, PH.D.; JOSEPH J. MARBACH, D.D.S.; JACK KLAUSNER, D.D.S.
he prognosis for patients with myofascial face pain, or MFP, is uncertain. The majority of studies,1-4 including a recent review,5 have suggested that the condition of most such patients improves over time, regardless of specific treatment. Others have questioned the generalizability of this conclusion.6,7 Contributing to the controversy may be the long-recognized heterogeneity of patients with MFP.8,9 The search for subgroups of patients with MFP who have different clinical courses may improve the accuracy of prognosis.10-12 One factor that may influence the course of MFP is the presence of comorbid conditions. Fibromyalgia, or FM, is one such disorder that may affect clinical presentation of MFP. FM, according to the most recent criteria established by the American College of Rheumatology, or ACR,13 is a syndrome involving widespread pain and pain on palpation at a minimum of 11 of 18 specific tender points. MFP is one of the most common types of temporomandibular joint disorders, or TMDs.14 According to the Research Diagnostic Criteria, or RDC, for TMDs,15 a diagnosis of MFP requires ache in the jaw, face or surrounding area, as well as pain on palpation at three or more of 20 specific facial muscle sites. Thus, the criteria for both disorders require pain on palpation at specific sites, but the sites do not overlap.16 Despite the
ABSTRACT Background. The authors conducted a study to determine whether there are differences in salient clinical characteristics between patients who have both myofascial face pain, or MFP, and comorbid fibromyalgia, or FM, and patients who have MFP but not FM. Methods. The authors enrolled in the study 162 female subjects who had histories of MFP. In physical examinations at the time of initial consultation, they recorded facial pain signs and symptoms. At the research interview follow-up (seven years postconsultation), participants were screened for a lifetime history of FM and other health problems. In addition, psychiatric interviewers conducted the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition–Revised, to assess each patient’s history of depression and other psychiatric disorders. Results. Of the 162 participants, 38 (23.5 percent) reported a history of FM. At the time of treatment for MFP, both the FM and non-FM groups had similar signs and symptoms of MFP. At the time of the research interview follow-up, participants with FM histories were significantly less likely than those without FM histories to report that they were free of MFP. On recall, those with FM histories reported experiencing more symptoms of MFP. Those with FM histories also were more likely to have had major depression and to report somatization symptoms. Finally, those who had FM more commonly had a history of facial pain’s interference with social and occupational functioning and had more severe pain than did those without FM. Conclusions. Patients who have MFP and a history of widespread pain suggestive of FM are likely to have more persistent and debilitating MFP and to have higher rates of depression and somatization symptoms than those who have no history of widespread pain.
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COVER STORY diagnostic segregation of the disorders, ample evidence exists that these disorders tend to cooccur. For more than 10 years,17 there have been suggestions that the disorders have a shared pathogenesis. COMORBIDITY OF MYOFASCIAL FACE PAIN AND FIBROMYALGIA
High rates of comorbidity between MFP and FM are wellestablished in clinical samples. An early report17 on a small sample of eight patients with FM found that six had severe signs of mandibular dysfunction associated with MFP. Shortly after that, Blasberg and Chalmers18 found that nearly all (95 percent) of their large cohort of patients from a facial pain clinic who had myofascial masticatory muscle problems had complaints beyond the jaw structure. Most complaints were of head, neck and back problems. Similar findings were reported by Hagberg and colleagues.19 Marbach20 reported that 23 percent of patients with MFP also reported that they had FM. These findings indicate that patients with MFP report high rates of widespread pain. More recent studies used standardized assessment of MFP using the RDC for TMDs,15 as well as standardized assessment of FM. Wright and colleagues21 examined a mixed group of patients who had facial pain but no prior rheumatic disorder diagnoses, and they reported that between 13 and 20 percent met some or all criteria for FM. Similarly, Plesh and colleagues22 found that 18 percent of patients with MFP met ACR13 criteria for FM. None of these studies provides contrasting FM diagnostic 162
rates in a control sample of subjects who did not have MFP. Nevertheless, rates are substantially elevated, since all FM rates in patients with MFP exceed population prevalence rates of 2 percent for FM.23 CLINICAL FEATURES OF MYOFASCIAL FACE PAIN AND FIBROMYALGIA
Several recent studies have compared features of patients with FM with those of patients with MFP. Plesh and colleagues22 found
The relevant issue for the clinician treating a patient with myofascial face pain is the extent to which clinical presentation and course will differ.
that patients with FM reported more psychological symptoms, more disability and more fatigue than patients with MFP. Another recent study concurred in finding increased fatigue and disability among patients who had FM compared with patients who had MFP. Interestingly, severity of facial pain did not differ between groups.24 This last finding was confirmed by two other groups of investigators25,26 studying patients who had either FM or MFP. Researchers in a final study, identifying facial pain subjects and those with more widespread pain from the general popula-
tion,27 did not concur, finding more facial pain signs and symptoms in the group with widespread pain. For the clinician treating a patient with MFP, none of these studies provides direct guidance about the consequences of comorbid FM. In all but the last population-based study, the FM group was defined by seeking treatment at a rheumatology clinic, while the patients with MFP sought treatment in a facial pain clinic. The relevant issue for the clinician treating a patient with MFP is the extent to which clinical presentation and course will differ, depending on whether the patient seeking treatment for MFP has comorbid FM. Studies comparing patient groups accrued from two different clinical settings cannot directly address this issue. Subjects recruited from different clinical settings may differ in a host of unmeasured factors associated with pathways into treatment, rather than with the specific disorder per se. This renders comparisons between groups problematic. In sum, no known study to date has specifically identified patients selected for MFP treatment and then compared the clinical profile of subgroups with and without widespread pain indicative of FM. The aim of our investigation was to fill that gap. METHODS
Subjects. Subjects with a history of MFP were drawn from the records of a clinician (J.J.M.) who specializes in the treatment of chronic facial pain. We used chart records to identify 1,013 women who had sought treatment with the clinician at least once since 1979 and
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY whose records indicated that they met diagnostic criteria for MFP at the time of consultation. Only women were selected, because the overwhelming majority of those who seek treatment for MFP are women.28-30 Only women who self-identified their race as white were selected, since there were few black or Hispanic women in the practice. Participants had to be current U.S. residents, between age 18 and 65 years of age and fluent speakers of English. The RDC for TMDs15 had not been published at the time we began the study. We made the diagnosis of MFP using the diagnostic criteria for temporomandibular pain–dysfunction syndrome established by the International Association for the Study of Pain31: tenderness in one or more muscles of mastication together with a clicking or popping noise in the temporomandibular joint and/or limitation of mandibular range. With some differences, this corresponds to the 1992 RDC category of “TMD (Myofascial subtype).” A sample of 443 subjects was randomly selected from the 1,013 patients who, according to records, appeared to meet study criteria. For other purposes not relevant to the investigation detailed here,32 we conducted a brief screening interview designed to oversample subjects with a history of major depressive disorder. After accounting for factors such as lack of current address, death of the patient, and other sources of demographic or diagnostic ineligibility, we identified 198 patients who met all study and screening criteria. Of these 198, 162 (82 percent)
completed all study phases relevant to the current investigation. Further details of subject selection procedures are available in earlier reports.32 MATERIALS
Health history. Interviewers who had master’s degrees in health-related fields conducted structured telephone interviews designed to record comprehensive physical health histories. As part of this interview, questions about 95 specific major physical conditions, including MFP and FM, were asked. A capsule description, in nontechnical language, was offered for physical disorders whose medical name might not be known by all respondents. For example, for FM, subjects were asked, “Have you ever had fibromyalgia, fibrositis or diffuse myofascial pain syndrome—that is, widespread pain in your muscles combined with tenderness to the touch in several points—for at least three months’ duration?” Similar capsule descriptions were presented for a wide range of pain-related conditions. For each disorder that the respondent reported, the interviewer asked questions about current status of the condition, date of onset, duration of disorder, treatment seeking, interference with social and occupational functioning, and severity of pain (if any). In addition, questions about lifetime occurrences of 48 specific symptoms, lasting at least six months, were asked. These included questions about MFPrelated symptoms and symptoms that were considered likely to be the result of somatization. Somatization-related symptoms are somatic com-
plaints that are unlikely to be fully explained by any known general medical condition and, therefore, are suggestive of a psychiatric condition. Such symptoms are suggestive of, but not specific to, a psychiatric diagnosis of somatoform disorder. In addition, the interview included structured questions about other health-related behaviors, such as history of use of alcohol and tobacco and current medication use. Myofascial face pain physical examination. At the time of initial consultation with the facial pain specialist (J.J.M.), each patient underwent a systematic examination. Results of this examination were recorded in closed-ended chart notes about principal complaints, sites of pain on palpation, range of motion and symptoms potentially related to other TMDs. Psychiatric history. Mental health clinicians who had Ph.D.-level degrees or were equivalent in experience were rigorously trained to directly interview study subjects by telephone to diagnose lifetime psychiatric disorders. They used the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition–Revised, or DSM-III-R,33—an instrument known by the abbreviation SCID and designed to enable trained clinicians to make reliable psychiatric research diagnoses according to the thencurrent DSM-III-R criteria. Each completed interview was taped and fully reviewed by a clinical supervisor to ensure reliability of diagnoses. Fortysix interview audiotapes, representing approximately every 12th completed SCID, were
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COVER STORY reviewed by both the clinical supervisor and a consultation/liaison psychiatrist to ensure reliability of the diagnosis of lifetime major depressive disorder. The Κ statistic—a measure of interrater agreement for categorical ratings— was .863, representing a disagreement about major depressive disorder status on only three of the 46 interviews. Discrepancies were resolved by consensus conference. In addition, the SCID was augmented with a structured series of questions designed to assess the possibility that symptoms of major depressive disorder were confounded with symptoms of physical health problems or substance use. If any of the potential confounders occurred just before or concurrent with the onset of symptoms of major depression, the participant’s case was reviewed by the consultation-liaison psychiatrist to determine the final diagnosis of major depression, organic mood disorder (that is, all symptoms of major depressive disorder judged to have been the result of a nonpsychiatric medical condition, medication or substance abuse) or depressive disorder not otherwise specified (that is, some, but not all, symptoms of major depressive disorder judged to have been the result of a nonpsychiatric medical condition, medication or substance abuse). RESULTS
Comorbid vs. regional myofascial face pain. Of the 162 MFP subjects, 38 (23.5 percent) reported a history of comorbid FM. These subjects are hereafter referred to as “comorbid” disorder study subjects. Those who did not report 164
having ever had comorbid FM but who had received a diagnosis of MFP on examination at the time of treatment (76.5 percent) are hereafter referred to as “regional” disorder study subjects. We used χ2 tests to compare comorbid and regional MFP subject groups on categorical measures. When small sample sizes per cell compromised the use of χ2 tests, we used Fisher exact tests. Independent sample t-tests compared the groups on continuous measures. Comorbid study subjects did not differ from regional study subjects in age at time of health history ascertainment (comorbid: mean = 41.67 [standard deviation, or SD, = 11.73]; regional: mean = 43.84 [SD = 10.96]; t = 1.05, P > .10), time between self-reported onset of MFP symptoms (ascertained during initial treatment with the facial pain clinician) and consultation with the pain clinician (comorbid: mean = 9.74 [SD = 4.79]; regional: mean = 8.78 [SD = 4.50]; t = −1.09, P > .10), or time between treatment by the pain clinician and time of health history ascertainment (comorbid: mean = 8.32 [SD = 4.95], regional: mean = 7.14 [SD = 4.58], t = −1.36, P > .10) Health histories were gathered an average of 7.1 years (SD = 4.7, median = 6) years after the initial MFP clinical examination. We determined the subjects’ current MFP status. Of the full group of 162 patients with MFP, 120 (74.1 percent) indicated that their facial pain problem was not “gone” or resolved at the time they provided their health history (that is, the facial pain
problem was reported as either “active” among 40.7 percent or “in remission, but not gone” among 33.3 percent). The rate of lifetime self-reported FM among those whose MFP was resolved was 4.8 percent . The rate of lifetime self-reported FM in the group whose MFP was unresolved was 30 percent (Fisher exact test, P < .001). Only one participant (2.6 percent) with comorbid FM reported that her FM was currently “gone,” with another 11 (28.9 percent) reporting that their FM was “in remission.” The balance of comorbid FM subjects (68.4 percent) reported that their FM was still “active.” Of the 37 comorbid subjects who were able to provide a date of onset at the time the health history was taken, the mean self-reported duration of FM was 11.3 years (SD = 9.65, median = eight years, minimum = < one year, maximum = 44 years). Among those with a history of comorbid FM and MFP who were able to provide dates of onset for each condition (n = 36), the majority (61.1 percent) provided the same year of onset for each condition. If onset dates were not in the same year, comorbid subjects more often dated onset of MFP first (27.8 percent) rather than FM first (11.1 percent). Symptom differences between groups. Data derived from MFP clinical examination were grouped into two general sets: symptoms likely to be TMD or MFP-related and symptoms likely to be FM-related. As shown in Table 1, comorbid and regional subjects did not differ significantly in frequency of endorsement of any chief complaint or on temporalis or mas-
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY TABLE 1
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN SYMPTOMS AT MFP TREATMENT. SYMPTOM
% COMORBID PATIENTS WITH MFP AND FM ‘YES’ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chief Complaint(s) TMJ ‡ pain
36.84
35.48
0.02
NS§
Earache
15.79
9.68
1.10
NS
Ear-area pain
28.85
23.39
0.48
NS
Mandible pain
21.05
16.13
0.49
NS
Face pain
10.53
10.48
0.00
NS
Cheek pain
42.11
39.52
0.08
NS
Temple pain
34.21
27.42
0.65
NS
TMJ crepitus
7.89
10.48
0.22
NS
TMJ clicking
39.47
38.71
0.01
NS
Pain on Palpation** In temporalis muscle
65.79
56.45
1.05
NS
In masseter muscle
84.21
79.03
0.49
NS
Pain reported to be “severe” at least some of the time
52.63
37.10
2.91
.088
* MFP: Myofascial face pain. † FM: Fibromyalgia. ‡ TMJ: Temporomandibular joint. § NS: Not significant. ** Unilateral or bilateral symptoms both scored as present (in other words, the patient answered “Yes” when asked if such symptoms were present).
seter muscle pain on palpation. There was a nonsignificant trend for comorbid subjects to indicate more often than regional subjects that their pain was “severe” at least some of the time. The two patient subgroups did not differ on mandibular range of motion (comorbid: mean = 32.74 mm [SD = 8.70]; regional: mean = 32.36 mm [SD = 7.53]; t = 0.24, P > .10). Table 2 details differences between comorbid and regional patient subgroups in symptoms potentially related to FM that were ascertained at time of
their clinical consultation about MFP. Complaints of pain in the back of the neck and shoulder were more frequent for comorbid subjects than for regional subjects. The one FM-related site in which palpation was conducted was the trapezius muscle. Differences between the groups were not statistically significant, although they were in the predicted direction. The clinical examination was conducted an average of seven years before ascertainment of health history, and selfreported onset of MFP was even more distant from health his-
tory ascertainment (see previous discussion). Therefore, we investigated whether comorbid subjects’ retrospective symptom reports derived from health histories differed from regional subjects’ reports of MFP symptoms in the health histories. As opposed to the clinical examination (Table 1), differences here were marked (Table 3). Comorbid subjects were more likely than regional subjects to report that they had ever had a period of six months or more in which they experienced pain on opening or chewing. They were also more likely to report
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COVER STORY TABLE 2
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FM SYMPTOMS AT MFP TREATMENT. SITE OF PAIN
% COMORBID PATIENTS WITH MFP AND FM ‘YES’ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chief Complaint(s) Side of neck
34.21
25.81
1.02
NS‡
Back of neck
52.63
25.81
9.60
.002
Occipital region
15.79
10.48
0.79
NS
Shoulder
50.00
16.94
17.10
.001
32.26
1.99
NS
Pain on Palpation§ 44.74
In trapezius muscle * † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. NS: Not significant. Unilateral or bilateral symptoms both scored as present (in other words, the patient answered “Yes” when asked if such symptoms were present).
TABLE 3
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN ON ANAMNESTIC HEALTH HISTORIES. % COMORBID PATIENTS WITH MFP AND FM ‘YES’‡ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chronic earaches
47.37
22.95
8.43
.004
Clicking or popping in jaw
72.22
68.52
0.18
NS§
Pain when opening mouth
88.89
53.27
14.54
.001
Pain when chewing
83.33
45.71
15.35
.001
Restricted jaw movement
84.21
46.34
16.84
.001
History of trauma to face
38.24
32.61
0.35
NS
SYMPTOM
* † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. “Yes” indicates that the subject said she had ever experienced the symptom for a period of at least six months NS: Not significant.
restricted jaw movement, despite the fact that these differences were not seen at the time of clinical examination. Comorbid and regional subjects did not differ in the proportion who recalled a history of trauma to the face before onset 166
of MFP. Using self-reported health histories again, we found that comorbid subjects reported more persistent MFP symptoms. Only 2.7 percent of comorbid subjects, vs. 25.0 percent of regional subjects, indi-
cated that their facial pain was gone (Fisher exact test, P < .001). They were equally likely to report that their facial pain was in remission (32.4 percent of comorbid subjects vs. 37.5 percent of regional subjects). Comorbid subjects (64.9
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY TABLE 4
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN ON SOMATIZATION ANAMNESTIC HEALTH HISTORIES. SYMPTOM
% COMORBID PATIENTS WITH MFP AND FM ‘YES’‡ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Nausea, not associated with pregnancy
28.95
9.68
8.89
.003
Abdominal pain not associated with menstruation
42.11
29.03
2.28
NS§
Bloating or gassiness
47.37
26.61
5.81
.016
Chronic diarrhea
18.42
15.32
0.21
NS
Chronic constipation
34.21
27.42
0.65
NS
Intolerance of several foods
34.21
20.16
3.20
.074
Chronic pain during urination
18.42
5.65
6.01
.014
Chronic shortness of breath
28.95
14.52
4.12
.042
Palpitations or pounding of heart
31.58
16.26
4.28
.039
Tingling or numbness
44.74
24.19
5.96
.015
Chronically swollen glands
21.62
6.45
7.33
.007
Irregular heartbeat
21.05
15.32
0.688
NS
Chronic dizziness
36.84
12.90
11.05
.001
Chronic difficulty in swallowing
39.47
8.06
21.99
.001
Burning in sex organs
13.16
4.03
4.18
.041
General fatigue
65.79
31.71
14.08
.001
Flushing or chills
36.84
16.13
7.53
.006
Dry mouth
28.95
10.57
7.73
.005
Blurred or double vision
10.53
3.23
3.30
.069
* † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. “Yes” indicates that the subject said she had ever experienced the symptom for a period of at least six months NS: Not significant.
percent) were more likely to indicate that their facial pain still was active than were regional subjects (37.5 percent) (χ2 = 12.00, P < .01). The two groups similarly reported the extent to which facial pain, at its worst, interfered with their ability to per-
form occupational roles of worker, homemaker or student (4-point scale on which 4 = no interference and 0 = a lot of interference) (comorbid: mean = 2.00 [SD = 1.65]; regional: mean = 2.33 [SD = 1.30]; t = 1.11, P > .10). However, when assessing the
extent to which MFP, at its worst, interfered with social activities (such as seeing friends and family or going out for fun) comorbid subjects (mean = 1.59, SD = 1.04) reported significantly more social interference than regional subjects (mean = 2.35,
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COVER STORY SD = 1.23) (t = 3.65, P < .001). Rating severity of pain, when facial pain was at its worst (on a 0 to 100 severity scale on which 0 represents no pain and 100 represents pain as bad as it could be), comorbid subjects recalled significantly higher severity of worst facial pain (mean = 89.0, SD = 17.66) than regional subjects (mean = 69.92, SD = 27.20) (t = −4.88, P < .0001). Psychiatric disorder and symptoms. Next, we examined relative rates of lifetime history of major depressive disorder in comorbid vs. regional subjects. The rate of the lifetime history of major depressive disorder was significantly higher in comorbid subjects (71.1 percent) than regional subjects (43.6 percent) (χ2 = 8.80, P < .01). Among those with a history of depression, the relative dating of the onset of MFP and depression did not differ for comorbid vs. regional MFP subjects: most reported an earlier onset of depression than of MFP (59.3 percent of comorbid vs. 58.5 percent of regional subjects), with similar proportions reporting earlier onset of MFP (37.0 percent of comorbid vs. 34.0 percent of regional subjects) and small proportions reporting the same year of onset for MFP and depression (3.7 percent of comorbid vs. 7.6 percent of regional subjects) (χ2 = 0.47, P > .10). Age of onset of depression did not differ between comorbid (mean = 30.48, SD = 9.01) and regional subjects (mean = 28.13, SD = 10.51) (t = −1.05, P > .10). Current rates of major depressive disorder were low and did not differ between comorbid (2.6 percent) and regional (4.0 percent) subjects (χ2 = 0.16, P > .10). Consistent with the pattern 168
of psychiatric histories assessed by clinical interviews, health history reports of specific physical symptoms that are likely to be a function of somatization rather than a major medical condition were generally higher in the comorbid than regional subgroups (Table 4). Of the 18 somatization-related symptoms explored, comorbid subjects were significantly more likely than regional subjects to indicate that they had ever had 13 of these complaints (for a period of six or more months); differences on the
The rate of the lifetime history of major depressive disorder was significantly higher in comorbid subjects than regional subjects.
balance of these symptoms were in the predicted direction, with somewhat higher endorsement by comorbid subjects. Health-related behaviors. Health-related behaviors did not differ significantly between groups. Comorbid subjects had a slight tendency to have smoked daily for a month or more at some point (65.8 percent) compared with regional subjects (50.8 percent), but these differences were not significant (χ2 = 2.63, P = .10). Daily use of caffeinated beverages did not differ between groups (79.0 percent of comor-
bid vs. 86.3 percent of regional subjects, χ2 = 1.20, P > .10). The average frequency of visits to a health professional were significantly higher for comorbid subjects (mean = 5.03, SD = 1.33) than regional subjects (mean = 4.00, SD = 1.46) (t = −4.08, P < .0001, where 1 = rarely or never, to 6 = once a month or more). Thus, comorbid subjects averaged from seven to 11 health-related visits per year, where regional subjects averaged three to six visits per year. Current physical health ratings were significantly poorer for comorbid subjects (mean = 2.71, SD = 0.96) than for regional subjects (mean = 2.11, SD = 0.77) (t = −3.56, P < .001, where 1 = excellent and 5 = very poor). The average number of medications used in the past month significantly differed for comorbid (mean = 4.87, SD = 2.82) and regional (mean = 3.20, SD = 2.44) subjects (t = −3.55, P < .001). DISCUSSION
Patterns of myofascial face pain/fibromyalgia comorbidity. This investigation compared two subgroups of patients who sought treatment for MFP. During a health history interview conducted an average of seven years later, nearly onefourth of these patients indicated that they also had a history of FM. For the “comorbid” patients with MFP and a self-diagnosis of FM, onsets of FM and MFP most often were reported to occur within the same year. If they did not, the facial pain problem most often predated the widespread one. This is inconsistent with a study of patients with FM who also had
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY comorbid MFP.34 Two-thirds of the comorbid patients in that study reported onset of general pain first. It is possible that recall might be affected by treatment setting; our patients were recruited after having sought MFP treatment, while the other study’s patients were recruited in the context of FM treatment. Psychiatric and psychosocial factors associated with comorbid fibromyalgia. Our finding of higher rates of psychiatric disorder among those with comorbid FM than those with MFP differs from that of an earlier investigation25 in which the researchers found no significant group differences in psychological profile. However, sample sizes in the earlier study were small and statistical power was low. Moreover, although differences in the earlier study were not statistically significant, symptom scores were directionally higher in the FM group on all six psychological scales used. While elevated rates of psychiatric disorder in FM can be interpreted from several different perspectives,35 the hypothesis that elevated rates of psychiatric disorder in FM are an artifact of examining an unrepresentative, treatmentseeking sample (in which those with psychiatric disorders are overrepresented) is not a tenable explanation here. This is because both MFP and FM subjects were drawn from the same treatment-seeking filter. It may be noted that, in this study, current major depression rates in MFP were low relative to lifetime rates of major depression. This is likely the result of two factors. First, we explicitly oversampled MFP cases with a history of major
depression for other study purposes (see Methods). Since this oversampling was not differential for those who had comorbid FM compared with those who had MFP alone, this does not bias between-group comparisons but makes interpretation of the proportion of current-tolifetime major depression invalid. Second, as nearly onethird of the study subjects described their MFP as being in remission, rates of current depression may be lower in this sample than in a sample of active patients with MFP who are depressed secondary to their pain. Those with comorbid FM also reported having experienced many more facial pain symptoms at the time of retrospective health histories, even though those higher symptom rates were not detected at the time of MFP examination. At the time the retrospective health history reports were collected, comorbid subjects more often recalled having experienced extended periods of somatization-related symptoms. Both the discrepancy between examination and recalled symptoms of facial pain and the higher rates of somatization-related symptoms in the FM group may be a function of hypervigilance among patients with FM, in which an unusual degree of attention is paid to external and internal noxious sensations.36,37 Alternately, these reports may be secondary to the higher lifetime rates of major depressive disorder that we detected in the comorbid patient group, leading to biased recall38 of earlier symptoms. The elevated rates of psychiatric and psychosocial factors in patients with MFP having
symptoms of comorbid FM is generally consistent with a wide range of studies22,24,25 whose findings indicated more psychiatric and psychosocial impairment among patients with FM than patients with MFP. Whether those seeking MFP treatment who also have FM differ psychosocially from patients seeking FM treatment in rheumatology settings cannot be addressed here, as it would require accrual of a sample of patients with FM from a rheumatology practice. Research limitations. Our study based assessment of FM status on patients’ self-report. The question inevitably arises about the validity of the selfreport diagnosis of FM and how this method might have affected our conclusions. Although the self-diagnosis of FM was made without the benefit of a physical examination, the 21 percent rate of selfassessed current FM among active patients with MFP—not detailed previously—is consistent with two other studies using examination for diagnosis of FM; one22 reported FM that met ACR-criteria in 18 percent of patients with MFP, and the other 21 reported that between 13 and 20 percent of a mixed group of facial pain patients with no prior rheumatic disorder diagnoses met some or all criteria for FM. Although the current research data do not allow for direct testing of the extent to which our self-diagnosis method corresponds with more standardized methods13 of assessing FM, other epidemiologic data suggest that self-report of widespread pain corresponds well (that is, positive predictive values of 70 percent or higher)
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COVER STORY with the standard clinical diagnosis of FM, especially among women.39 In addition, in this study, we have shown that pain in the back of the neck and shoulder on examination was more frequent among those who self-reported a history of FM. These comparisons lend validity to self-reports of FM used in this study. If self-diagnosis of FM contains random error, it is likely to have led to an underestimation of the magnitude of the relationship between FM/MFP comorbidity and a poor clinical course of MFP. Nevertheless, future researchers attempting replication of our findings would be encouraged to use state-of-theart FM diagnostic methods.13 Clinical implications. At the time of treatment for facial pain, MFP symptoms were similar among all subjects, whether they had comorbid widespread or only regional MFP complaints. By themselves, patterns of MFP signs and symptoms are unlikely to provide clues to the likelihood of a patient’s having comorbid FM. However, FM-related symptoms were detected at the time of facial pain treatment more often among those who had a later self-diagnosis of FM. This suggests that the clinician who sees a patient seeking treatment for MFP would be well-advised to ascertain the presence of symptoms related to FM. The screening for FM among patients seeking treatment for MFP is especially important, as course and outcome are likely to be different in patients with solely a regional vs. a widespread myofascial disorder. This study found that patients who had MFP and comorbid self-assessed FM were less likely to say that their facial pain symptoms were 170
gone at the time of follow-up health history assessment. Comorbid patients recalled that their MFP problem more often interfered with social functioning and that the severity of pain was higher than among those who did not report having FM. The impact and prevalence of comorbid FM on MFP is likely to be greatest in tertiary care settings, in which patients with more chronic MFP are likely to be seen. The fact that we did not employ standardized FM diagnostic methods is clearly a research limitation. However, the self-report method we used may lend itself better to clinical application. Given the constraints of routine dental practice, it is unreasonable to expect the clinician to conduct a full diagnostic assessment of FM for all patients with MFP. Screening for FM, by asking patients with MFP about their history of widespread pain, is a manageable task in most clinical settings. In addition, a patient’s report of neck and shoulder pain should raise the dentist’s index of suspicion about the possibility of FM. Our finding that MFP comorbid with FM is more recalcitrant to treatment than MFP alone is important. It confirms the observations made in a recent study34 of patients with FM, 39 of whom had comorbid MFP. Among the 75 percent of patients with comorbid MFP and FM in that study who sought treatment, all indicated that their MFP treatment—typically oral appliances—was ineffective. Given these data and other data questioning the efficacy of oral appliances40,41 in treating MFP, the dentist is uniquely qualified to advise the
patient with FM/MFP about the devices’ potentially limited use. Although our study was not designed specifically to test the differential efficacy of particular MFP treatments for those with comorbid widespread vs. regional MFP, such studies are clearly needed. As we await more research explicating the customization of MFP treatment for comorbid widespread vs. regional MFP, what treatment recommendations can be made? If the patient’s reported symptoms suggest that he or she may have FM, referral to a rheumatologist for FM diagnostic assessment is recommended. However, this does not mean that dentists should abdicate their role in treatment of MFP, as “physicians have relegated the treatment of chronic musculoskeletal facial pain to the dental realm.”16(p.477) Low-dose tricyclic antidepressants, exercise and intramuscular injections—treatments advocated for both FM and MFP16—may be uniquely indicated for treatment of MFP in those who have comorbid FM. These treatments may be indicated particularly for patients in whom more conservative treatments, such as vapocoolant sprays and analgesics, are not effective. CONCLUSION
A retrospective study such as the one described here cannot firmly address issues surrounding similar or different pathogenesis of FM vs. MFP. Nor can it evaluate the plausibility of different explanatory models for the association between FM and MFP.42 Our data suggest the possibility that MFP secondary to FM is a different clinical entity than MFP secondary to
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY other causes. Other studies will be needed to confirm this possibility. Our findings, however, are clinically significant in that they show that the course of, outcome of and disability associated with MFP are influenced by whether MFP is accompanied by symptoms of FM. Thus, it is recommended that symptoms of FM be assessed among patients seeking treatment of a regional myofascial problem such as MFP. ■ Dr. Raphael is an associate professor, New Jersey Medical School, Department of Psychiatry, and New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, 30 Bergen St., ADMC 14, Newark, N.J. 07107. Address reprint requests to Dr. Raphael. Dr. Marbach is a professor, New Jersey Medical School, Department of Psychiatry, and Robert and Susan Carmel professor in algesiology, New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, Newark. Dr. Klausner is an instructor, New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, Newark. He also is in private practice in Boston. This study was supported by National Institute of Dental and Craniofacial Research grants DE05989 and DE11714, as well as grants from the J. Aron Charitable Foundation and the Revlon Foundation. 1. Greene CS, Laskin DM. Long-term evaluation of treatment for myofascial pain-dysfunction syndrome: a comparative analysis. JADA 1983;107(12):235-8. 2. Randolph CS, Greene CS, Moretti R, Forbes D, Perry HT. Conservative management of temporomandibular disorders: a posttreatment comparison between patients from a university clinic and from private practice. Am J Orthod Dentofacial Orthop 1990;98(1):77-82. 3. Wedel A, Carlsson GE. A four-year follow-up, by means of questionnaire, of patients with functional disturbances of the masticatory system. J Oral Rehabil 1986;13(2):105-13. 4. Ohrbach R, Dworkin SF. Five-year outcomes in TMD: relationship of changes in pain to changes in physical and psychological variables. Pain 1998;74(2-3):315-26. 5. Drangsholt M, LeResche L. Temporomandibular disorder pain. In: Crombie IK, Croft PR, Linton SJ, LeResche L, Von Korff, M, eds. Epidemiology of pain: A report of the Task Force on Epidemiology of the International Association for the Study of Pain. Seattle: IASP Press; 1999: 203-34. 6. Raphael KG, Marbach JJ. A year of chronic
TMPDS: evaluating patients’ pain patterns. JADA 1992;123(11):53-8. 7. Raphael KG, Marbach JJ. Comments on Ohrbach and Dworkin, Pain, 74 (1998) 315-26. Studies on factors predicting the longterm outcome of pain disorders and TMDs. Pain 1999;79(2-3):319-23. 8. Reene CS, Lerman MD, Sutcher HD, Laskin DM. The TMJ pain-dysfunction syndrome: heterogeneity of the patient population. JADA 1969;79:1168-72. 9. Wedel A. Heterogeneity of patients with craniomandibular disorders. a longitudinal study. Swed Dent J Suppl 1988;55:1-51. 10. Rudy TE, Turk DC, Kubinski JA, Zaki HS. Differential treatment responses of TMD patients as a function of psychological characteristics. Pain 1995;61(1):103-12. 11. Fricton JR, Olsen T. Predictors of outcome for treatment of temporomandibular disorders. J Orofac Pain 1996;10(1):54-65. 12. Krogstad BS, Jokstad A, Dahl BL, Vassend O. Relationships between risk factors and treatment outcome in a group of patients with temporomandibular disorders. J Orofac Pain 1996;10(1):48-53. 13. Wolfe, F, Smythe HA, Yunus MB, et al. The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis Rheum 1990;33(2):160-72. 14. LeResche L. Research diagnostic criteria for temporomandibular disorders. In: Fricton, JR, Dubner R, eds. Orofacial pain and temporomandibular disorders. New York: Raven Press; 1995:189-203. 15. Dworkin SF, LeResche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examinations and specifications, critique. J Craniomandib Disord 1992;6(4):30055. 16. Marbach JJ. Temporomandibular pain and dysfunction syndrome: history, physical examination, and treatment. Rheum Dis Clin North Am 1996:22(3):477-98. 17. Eriksson PO, Lindman R, Stal P, Bengtsson A. Symptoms and signs of mandibular dysfunction in primary fibromyalgia syndrome (PSF) patients. Swed Dent J 1988;12(4):141-9. 18. Blasberg B, Chalmers A. Temporomandibular pain and dysfunction syndrome associated with generalized musculoskeletal pain: a retrospective study. J Rheumatol Suppl 1989;19:87-90. 19. Hagberg C, Hagberg M, Kopp S. Musculoskeletal symptoms and psychosocial factors among patients with craniomandibular disorders. Acta Odontol Scand 1994;52(3):170-7. 20. Marbach JJ. Is myofascial face pain a regional expression of fibromyalgia? J Musculoskeletal Pain 1995;3(2):93-97. 21. Wright EF, Des Rosier KF, Clark MK, Bifano SL. Identifying undiagnosed rheumatic disorders among patients with TMD. JADA 1997;128:738-44. 22. Plesh O, Wolfe F, Lane N. The relationship between fibromyalgia and temporomandibular disorders: prevalence and symptom severity, J Rheumatol 1996;23:1948-52. 23. Wolfe F, Ross K, Anderson J, Russell IJ, Hebert L. The prevalence and characteristics of fibromyalgia in the general population. Arthritis Rheum 1995;38(1):19-28. 24. Dao TT, Reynolds WJ, Tenenbaum HC. Comorbidity between myofascial pain of the masticatory muscles and fibromyalgia. J Orofac Pain 1997;11:232-41.
25. Cimino R, Michelotti A, Stradi R, Farinaro C. Comparison of clinical and psychologic features of fibromyalgia and masticatory myofascial pain. J Orofac Pain 1998;12(1):35-41. 26. Hedenberg-Magnusson B, Ernberg M, Kopp S. Symptoms and signs of temporomandibular disorders in patients with fibromyalgia and local myalgia of the temporomandibular system: a comparative study. Acta Odontol Scand 1997;55:344-9. 27. Wanman A. The relationship between muscle tenderness and craniomandibular disorders: a study of 35-year-olds from the general population. J Orofac Pain 1995;9: 235-43. 28. Dworkin SF, Huggins KH, LeResche L, et al. Epidemiology of signs and symptoms in temporomandibular disorders: clinical signs in cases and controls. JADA 1990;120:273-81. 29. LeResche L. Epidemiology of temporomandibular disorders: implications for the investigation of etiologic factors. Crit Rev Oral Biol Med 1997;8(3):291-305. 30. Marbach JJ, Ballard GT, Frankel MR, Raphael KG. Patterns of TMJ surgery: evidence of sex differences. JADA 1997;128:609-14. 31. International Association for the Study of Pain. Classification of chronic pain. Pain 1986;3(suppl):59-60S. 32. Dohrenwend BP, Raphael KG, Marbach JJ, Gallagher RM. Why is depression co-morbid with chronic myofascial face pain? A family study test of alternative hypotheses. Pain 1999;83:183-92. 33. Spitzer RL, Williams JBW, Gibbon M, First M. Instruction manual for the structured clinical interview for DSM-III-R. New York: NYS Psychiatric Institute Biometrics Research; 1988. 34. Korszun A, Papadopoulos E, Demitrack M, Engelberg C, Crofford L. The relationship between temporomandibular disorders and stress-associated syndromes. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86(4):41620. 35. White KP, Nielson W, Harth M. Psychological distress and healthcare seeking behavior: caution warranted in interpreting data. J Rheumatol 1999;26:244-6. 36. McDermid AJ, Rollman GB, McCain GA. Generalized hypervigilance in fibromyalgia: evidence of perceptual amplification. Pain 1996;66:133-44. 37. Scudds RA, Rollman GB, Harth M, McCain GA. Pain perception and personality measures as discriminators in the classification of fibrositis. J Rheumatol 1987;14:563-9. 38. Raphael KG, Cloitre M. Does mood congruence or causal search govern recall bias? A test of life event recall. J Clin Epidemiol 1994;47(5):55564. 39. White KP, Harth M, Speechley M, Ostbye T. Testing an instrument to screen for fibromyalgia syndrome in general population studies: the London Fibromyalgia Epidemiology Study Screening Questionnaire. J Rheumatol 1999;26(4):880-4. 40. Marbach JJ, Raphael KG. Treatment of chronic musculoskeletal facial pain: the role of evidence-based care. Oral Surg Oral Med Oral Pathol 1997;83:170-6. 41. Raphael KG, Marbach JJ. Evidence-based care of musculoskeletal facial pain: implications for the clinical science of dentistry. JADA 1997;128:73-9. 42. Wolfe F. Fibromyalgia. In: Sessle BJ, Bryant PS, Dionne RA, eds. Temporomandibular disorders and related pain conditions. Vol. 4. Seattle: IASP Press; 1995.
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ARTICLE 1
C O V E R S T O R Y
MYOFASCIAL FACE PAIN
Clinical Characteristics of Those With Regional vs. Widespread Pain KAREN G. RAPHAEL, PH.D.; JOSEPH J. MARBACH, D.D.S.; JACK KLAUSNER, D.D.S.
he prognosis for patients with myofascial face pain, or MFP, is uncertain. The majority of studies,1-4 including a recent review,5 have suggested that the condition of most such patients improves over time, regardless of specific treatment. Others have questioned the generalizability of this conclusion.6,7 Contributing to the controversy may be the long-recognized heterogeneity of patients with MFP.8,9 The search for subgroups of patients with MFP who have different clinical courses may improve the accuracy of prognosis.10-12 One factor that may influence the course of MFP is the presence of comorbid conditions. Fibromyalgia, or FM, is one such disorder that may affect clinical presentation of MFP. FM, according to the most recent criteria established by the American College of Rheumatology, or ACR,13 is a syndrome involving widespread pain and pain on palpation at a minimum of 11 of 18 specific tender points. MFP is one of the most common types of temporomandibular joint disorders, or TMDs.14 According to the Research Diagnostic Criteria, or RDC, for TMDs,15 a diagnosis of MFP requires ache in the jaw, face or surrounding area, as well as pain on palpation at three or more of 20 specific facial muscle sites. Thus, the criteria for both disorders require pain on palpation at specific sites, but the sites do not overlap.16 Despite the
ABSTRACT Background. The authors conducted a study to determine whether there are differences in salient clinical characteristics between patients who have both myofascial face pain, or MFP, and comorbid fibromyalgia, or FM, and patients who have MFP but not FM. Methods. The authors enrolled in the study 162 female subjects who had histories of MFP. In physical examinations at the time of initial consultation, they recorded facial pain signs and symptoms. At the research interview follow-up (seven years postconsultation), participants were screened for a lifetime history of FM and other health problems. In addition, psychiatric interviewers conducted the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition–Revised, to assess each patient’s history of depression and other psychiatric disorders. Results. Of the 162 participants, 38 (23.5 percent) reported a history of FM. At the time of treatment for MFP, both the FM and non-FM groups had similar signs and symptoms of MFP. At the time of the research interview follow-up, participants with FM histories were significantly less likely than those without FM histories to report that they were free of MFP. On recall, those with FM histories reported experiencing more symptoms of MFP. Those with FM histories also were more likely to have had major depression and to report somatization symptoms. Finally, those who had FM more commonly had a history of facial pain’s interference with social and occupational functioning and had more severe pain than did those without FM. Conclusions. Patients who have MFP and a history of widespread pain suggestive of FM are likely to have more persistent and debilitating MFP and to have higher rates of depression and somatization symptoms than those who have no history of widespread pain.
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COVER STORY diagnostic segregation of the disorders, ample evidence exists that these disorders tend to cooccur. For more than 10 years,17 there have been suggestions that the disorders have a shared pathogenesis. COMORBIDITY OF MYOFASCIAL FACE PAIN AND FIBROMYALGIA
High rates of comorbidity between MFP and FM are wellestablished in clinical samples. An early report17 on a small sample of eight patients with FM found that six had severe signs of mandibular dysfunction associated with MFP. Shortly after that, Blasberg and Chalmers18 found that nearly all (95 percent) of their large cohort of patients from a facial pain clinic who had myofascial masticatory muscle problems had complaints beyond the jaw structure. Most complaints were of head, neck and back problems. Similar findings were reported by Hagberg and colleagues.19 Marbach20 reported that 23 percent of patients with MFP also reported that they had FM. These findings indicate that patients with MFP report high rates of widespread pain. More recent studies used standardized assessment of MFP using the RDC for TMDs,15 as well as standardized assessment of FM. Wright and colleagues21 examined a mixed group of patients who had facial pain but no prior rheumatic disorder diagnoses, and they reported that between 13 and 20 percent met some or all criteria for FM. Similarly, Plesh and colleagues22 found that 18 percent of patients with MFP met ACR13 criteria for FM. None of these studies provides contrasting FM diagnostic 162
rates in a control sample of subjects who did not have MFP. Nevertheless, rates are substantially elevated, since all FM rates in patients with MFP exceed population prevalence rates of 2 percent for FM.23 CLINICAL FEATURES OF MYOFASCIAL FACE PAIN AND FIBROMYALGIA
Several recent studies have compared features of patients with FM with those of patients with MFP. Plesh and colleagues22 found
The relevant issue for the clinician treating a patient with myofascial face pain is the extent to which clinical presentation and course will differ.
that patients with FM reported more psychological symptoms, more disability and more fatigue than patients with MFP. Another recent study concurred in finding increased fatigue and disability among patients who had FM compared with patients who had MFP. Interestingly, severity of facial pain did not differ between groups.24 This last finding was confirmed by two other groups of investigators25,26 studying patients who had either FM or MFP. Researchers in a final study, identifying facial pain subjects and those with more widespread pain from the general popula-
tion,27 did not concur, finding more facial pain signs and symptoms in the group with widespread pain. For the clinician treating a patient with MFP, none of these studies provides direct guidance about the consequences of comorbid FM. In all but the last population-based study, the FM group was defined by seeking treatment at a rheumatology clinic, while the patients with MFP sought treatment in a facial pain clinic. The relevant issue for the clinician treating a patient with MFP is the extent to which clinical presentation and course will differ, depending on whether the patient seeking treatment for MFP has comorbid FM. Studies comparing patient groups accrued from two different clinical settings cannot directly address this issue. Subjects recruited from different clinical settings may differ in a host of unmeasured factors associated with pathways into treatment, rather than with the specific disorder per se. This renders comparisons between groups problematic. In sum, no known study to date has specifically identified patients selected for MFP treatment and then compared the clinical profile of subgroups with and without widespread pain indicative of FM. The aim of our investigation was to fill that gap. METHODS
Subjects. Subjects with a history of MFP were drawn from the records of a clinician (J.J.M.) who specializes in the treatment of chronic facial pain. We used chart records to identify 1,013 women who had sought treatment with the clinician at least once since 1979 and
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COVER STORY whose records indicated that they met diagnostic criteria for MFP at the time of consultation. Only women were selected, because the overwhelming majority of those who seek treatment for MFP are women.28-30 Only women who self-identified their race as white were selected, since there were few black or Hispanic women in the practice. Participants had to be current U.S. residents, between age 18 and 65 years of age and fluent speakers of English. The RDC for TMDs15 had not been published at the time we began the study. We made the diagnosis of MFP using the diagnostic criteria for temporomandibular pain–dysfunction syndrome established by the International Association for the Study of Pain31: tenderness in one or more muscles of mastication together with a clicking or popping noise in the temporomandibular joint and/or limitation of mandibular range. With some differences, this corresponds to the 1992 RDC category of “TMD (Myofascial subtype).” A sample of 443 subjects was randomly selected from the 1,013 patients who, according to records, appeared to meet study criteria. For other purposes not relevant to the investigation detailed here,32 we conducted a brief screening interview designed to oversample subjects with a history of major depressive disorder. After accounting for factors such as lack of current address, death of the patient, and other sources of demographic or diagnostic ineligibility, we identified 198 patients who met all study and screening criteria. Of these 198, 162 (82 percent)
completed all study phases relevant to the current investigation. Further details of subject selection procedures are available in earlier reports.32 MATERIALS
Health history. Interviewers who had master’s degrees in health-related fields conducted structured telephone interviews designed to record comprehensive physical health histories. As part of this interview, questions about 95 specific major physical conditions, including MFP and FM, were asked. A capsule description, in nontechnical language, was offered for physical disorders whose medical name might not be known by all respondents. For example, for FM, subjects were asked, “Have you ever had fibromyalgia, fibrositis or diffuse myofascial pain syndrome—that is, widespread pain in your muscles combined with tenderness to the touch in several points—for at least three months’ duration?” Similar capsule descriptions were presented for a wide range of pain-related conditions. For each disorder that the respondent reported, the interviewer asked questions about current status of the condition, date of onset, duration of disorder, treatment seeking, interference with social and occupational functioning, and severity of pain (if any). In addition, questions about lifetime occurrences of 48 specific symptoms, lasting at least six months, were asked. These included questions about MFPrelated symptoms and symptoms that were considered likely to be the result of somatization. Somatization-related symptoms are somatic com-
plaints that are unlikely to be fully explained by any known general medical condition and, therefore, are suggestive of a psychiatric condition. Such symptoms are suggestive of, but not specific to, a psychiatric diagnosis of somatoform disorder. In addition, the interview included structured questions about other health-related behaviors, such as history of use of alcohol and tobacco and current medication use. Myofascial face pain physical examination. At the time of initial consultation with the facial pain specialist (J.J.M.), each patient underwent a systematic examination. Results of this examination were recorded in closed-ended chart notes about principal complaints, sites of pain on palpation, range of motion and symptoms potentially related to other TMDs. Psychiatric history. Mental health clinicians who had Ph.D.-level degrees or were equivalent in experience were rigorously trained to directly interview study subjects by telephone to diagnose lifetime psychiatric disorders. They used the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition–Revised, or DSM-III-R,33—an instrument known by the abbreviation SCID and designed to enable trained clinicians to make reliable psychiatric research diagnoses according to the thencurrent DSM-III-R criteria. Each completed interview was taped and fully reviewed by a clinical supervisor to ensure reliability of diagnoses. Fortysix interview audiotapes, representing approximately every 12th completed SCID, were
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COVER STORY reviewed by both the clinical supervisor and a consultation/liaison psychiatrist to ensure reliability of the diagnosis of lifetime major depressive disorder. The Κ statistic—a measure of interrater agreement for categorical ratings— was .863, representing a disagreement about major depressive disorder status on only three of the 46 interviews. Discrepancies were resolved by consensus conference. In addition, the SCID was augmented with a structured series of questions designed to assess the possibility that symptoms of major depressive disorder were confounded with symptoms of physical health problems or substance use. If any of the potential confounders occurred just before or concurrent with the onset of symptoms of major depression, the participant’s case was reviewed by the consultation-liaison psychiatrist to determine the final diagnosis of major depression, organic mood disorder (that is, all symptoms of major depressive disorder judged to have been the result of a nonpsychiatric medical condition, medication or substance abuse) or depressive disorder not otherwise specified (that is, some, but not all, symptoms of major depressive disorder judged to have been the result of a nonpsychiatric medical condition, medication or substance abuse). RESULTS
Comorbid vs. regional myofascial face pain. Of the 162 MFP subjects, 38 (23.5 percent) reported a history of comorbid FM. These subjects are hereafter referred to as “comorbid” disorder study subjects. Those who did not report 164
having ever had comorbid FM but who had received a diagnosis of MFP on examination at the time of treatment (76.5 percent) are hereafter referred to as “regional” disorder study subjects. We used χ2 tests to compare comorbid and regional MFP subject groups on categorical measures. When small sample sizes per cell compromised the use of χ2 tests, we used Fisher exact tests. Independent sample t-tests compared the groups on continuous measures. Comorbid study subjects did not differ from regional study subjects in age at time of health history ascertainment (comorbid: mean = 41.67 [standard deviation, or SD, = 11.73]; regional: mean = 43.84 [SD = 10.96]; t = 1.05, P > .10), time between self-reported onset of MFP symptoms (ascertained during initial treatment with the facial pain clinician) and consultation with the pain clinician (comorbid: mean = 9.74 [SD = 4.79]; regional: mean = 8.78 [SD = 4.50]; t = −1.09, P > .10), or time between treatment by the pain clinician and time of health history ascertainment (comorbid: mean = 8.32 [SD = 4.95], regional: mean = 7.14 [SD = 4.58], t = −1.36, P > .10) Health histories were gathered an average of 7.1 years (SD = 4.7, median = 6) years after the initial MFP clinical examination. We determined the subjects’ current MFP status. Of the full group of 162 patients with MFP, 120 (74.1 percent) indicated that their facial pain problem was not “gone” or resolved at the time they provided their health history (that is, the facial pain
problem was reported as either “active” among 40.7 percent or “in remission, but not gone” among 33.3 percent). The rate of lifetime self-reported FM among those whose MFP was resolved was 4.8 percent . The rate of lifetime self-reported FM in the group whose MFP was unresolved was 30 percent (Fisher exact test, P < .001). Only one participant (2.6 percent) with comorbid FM reported that her FM was currently “gone,” with another 11 (28.9 percent) reporting that their FM was “in remission.” The balance of comorbid FM subjects (68.4 percent) reported that their FM was still “active.” Of the 37 comorbid subjects who were able to provide a date of onset at the time the health history was taken, the mean self-reported duration of FM was 11.3 years (SD = 9.65, median = eight years, minimum = < one year, maximum = 44 years). Among those with a history of comorbid FM and MFP who were able to provide dates of onset for each condition (n = 36), the majority (61.1 percent) provided the same year of onset for each condition. If onset dates were not in the same year, comorbid subjects more often dated onset of MFP first (27.8 percent) rather than FM first (11.1 percent). Symptom differences between groups. Data derived from MFP clinical examination were grouped into two general sets: symptoms likely to be TMD or MFP-related and symptoms likely to be FM-related. As shown in Table 1, comorbid and regional subjects did not differ significantly in frequency of endorsement of any chief complaint or on temporalis or mas-
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY TABLE 1
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN SYMPTOMS AT MFP TREATMENT. SYMPTOM
% COMORBID PATIENTS WITH MFP AND FM ‘YES’ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chief Complaint(s) TMJ ‡ pain
36.84
35.48
0.02
NS§
Earache
15.79
9.68
1.10
NS
Ear-area pain
28.85
23.39
0.48
NS
Mandible pain
21.05
16.13
0.49
NS
Face pain
10.53
10.48
0.00
NS
Cheek pain
42.11
39.52
0.08
NS
Temple pain
34.21
27.42
0.65
NS
TMJ crepitus
7.89
10.48
0.22
NS
TMJ clicking
39.47
38.71
0.01
NS
Pain on Palpation** In temporalis muscle
65.79
56.45
1.05
NS
In masseter muscle
84.21
79.03
0.49
NS
Pain reported to be “severe” at least some of the time
52.63
37.10
2.91
.088
* MFP: Myofascial face pain. † FM: Fibromyalgia. ‡ TMJ: Temporomandibular joint. § NS: Not significant. ** Unilateral or bilateral symptoms both scored as present (in other words, the patient answered “Yes” when asked if such symptoms were present).
seter muscle pain on palpation. There was a nonsignificant trend for comorbid subjects to indicate more often than regional subjects that their pain was “severe” at least some of the time. The two patient subgroups did not differ on mandibular range of motion (comorbid: mean = 32.74 mm [SD = 8.70]; regional: mean = 32.36 mm [SD = 7.53]; t = 0.24, P > .10). Table 2 details differences between comorbid and regional patient subgroups in symptoms potentially related to FM that were ascertained at time of
their clinical consultation about MFP. Complaints of pain in the back of the neck and shoulder were more frequent for comorbid subjects than for regional subjects. The one FM-related site in which palpation was conducted was the trapezius muscle. Differences between the groups were not statistically significant, although they were in the predicted direction. The clinical examination was conducted an average of seven years before ascertainment of health history, and selfreported onset of MFP was even more distant from health his-
tory ascertainment (see previous discussion). Therefore, we investigated whether comorbid subjects’ retrospective symptom reports derived from health histories differed from regional subjects’ reports of MFP symptoms in the health histories. As opposed to the clinical examination (Table 1), differences here were marked (Table 3). Comorbid subjects were more likely than regional subjects to report that they had ever had a period of six months or more in which they experienced pain on opening or chewing. They were also more likely to report
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COVER STORY TABLE 2
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FM SYMPTOMS AT MFP TREATMENT. SITE OF PAIN
% COMORBID PATIENTS WITH MFP AND FM ‘YES’ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chief Complaint(s) Side of neck
34.21
25.81
1.02
NS‡
Back of neck
52.63
25.81
9.60
.002
Occipital region
15.79
10.48
0.79
NS
Shoulder
50.00
16.94
17.10
.001
32.26
1.99
NS
Pain on Palpation§ 44.74
In trapezius muscle * † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. NS: Not significant. Unilateral or bilateral symptoms both scored as present (in other words, the patient answered “Yes” when asked if such symptoms were present).
TABLE 3
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN ON ANAMNESTIC HEALTH HISTORIES. % COMORBID PATIENTS WITH MFP AND FM ‘YES’‡ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Chronic earaches
47.37
22.95
8.43
.004
Clicking or popping in jaw
72.22
68.52
0.18
NS§
Pain when opening mouth
88.89
53.27
14.54
.001
Pain when chewing
83.33
45.71
15.35
.001
Restricted jaw movement
84.21
46.34
16.84
.001
History of trauma to face
38.24
32.61
0.35
NS
SYMPTOM
* † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. “Yes” indicates that the subject said she had ever experienced the symptom for a period of at least six months NS: Not significant.
restricted jaw movement, despite the fact that these differences were not seen at the time of clinical examination. Comorbid and regional subjects did not differ in the proportion who recalled a history of trauma to the face before onset 166
of MFP. Using self-reported health histories again, we found that comorbid subjects reported more persistent MFP symptoms. Only 2.7 percent of comorbid subjects, vs. 25.0 percent of regional subjects, indi-
cated that their facial pain was gone (Fisher exact test, P < .001). They were equally likely to report that their facial pain was in remission (32.4 percent of comorbid subjects vs. 37.5 percent of regional subjects). Comorbid subjects (64.9
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY TABLE 4
DIFFERENCES BETWEEN MFP* PATIENTS WITH AND WITHOUT SELF-REPORTED FM† ON FACIAL PAIN ON SOMATIZATION ANAMNESTIC HEALTH HISTORIES. SYMPTOM
% COMORBID PATIENTS WITH MFP AND FM ‘YES’‡ n = 38
% REGIONAL PATIENTS WITH MFP ONLY ‘YES’ n = 124
χ2 VALUE
P VALUE
Nausea, not associated with pregnancy
28.95
9.68
8.89
.003
Abdominal pain not associated with menstruation
42.11
29.03
2.28
NS§
Bloating or gassiness
47.37
26.61
5.81
.016
Chronic diarrhea
18.42
15.32
0.21
NS
Chronic constipation
34.21
27.42
0.65
NS
Intolerance of several foods
34.21
20.16
3.20
.074
Chronic pain during urination
18.42
5.65
6.01
.014
Chronic shortness of breath
28.95
14.52
4.12
.042
Palpitations or pounding of heart
31.58
16.26
4.28
.039
Tingling or numbness
44.74
24.19
5.96
.015
Chronically swollen glands
21.62
6.45
7.33
.007
Irregular heartbeat
21.05
15.32
0.688
NS
Chronic dizziness
36.84
12.90
11.05
.001
Chronic difficulty in swallowing
39.47
8.06
21.99
.001
Burning in sex organs
13.16
4.03
4.18
.041
General fatigue
65.79
31.71
14.08
.001
Flushing or chills
36.84
16.13
7.53
.006
Dry mouth
28.95
10.57
7.73
.005
Blurred or double vision
10.53
3.23
3.30
.069
* † ‡ §
MFP: Myofascial face pain. FM: Fibromyalgia. “Yes” indicates that the subject said she had ever experienced the symptom for a period of at least six months NS: Not significant.
percent) were more likely to indicate that their facial pain still was active than were regional subjects (37.5 percent) (χ2 = 12.00, P < .01). The two groups similarly reported the extent to which facial pain, at its worst, interfered with their ability to per-
form occupational roles of worker, homemaker or student (4-point scale on which 4 = no interference and 0 = a lot of interference) (comorbid: mean = 2.00 [SD = 1.65]; regional: mean = 2.33 [SD = 1.30]; t = 1.11, P > .10). However, when assessing the
extent to which MFP, at its worst, interfered with social activities (such as seeing friends and family or going out for fun) comorbid subjects (mean = 1.59, SD = 1.04) reported significantly more social interference than regional subjects (mean = 2.35,
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167
COVER STORY SD = 1.23) (t = 3.65, P < .001). Rating severity of pain, when facial pain was at its worst (on a 0 to 100 severity scale on which 0 represents no pain and 100 represents pain as bad as it could be), comorbid subjects recalled significantly higher severity of worst facial pain (mean = 89.0, SD = 17.66) than regional subjects (mean = 69.92, SD = 27.20) (t = −4.88, P < .0001). Psychiatric disorder and symptoms. Next, we examined relative rates of lifetime history of major depressive disorder in comorbid vs. regional subjects. The rate of the lifetime history of major depressive disorder was significantly higher in comorbid subjects (71.1 percent) than regional subjects (43.6 percent) (χ2 = 8.80, P < .01). Among those with a history of depression, the relative dating of the onset of MFP and depression did not differ for comorbid vs. regional MFP subjects: most reported an earlier onset of depression than of MFP (59.3 percent of comorbid vs. 58.5 percent of regional subjects), with similar proportions reporting earlier onset of MFP (37.0 percent of comorbid vs. 34.0 percent of regional subjects) and small proportions reporting the same year of onset for MFP and depression (3.7 percent of comorbid vs. 7.6 percent of regional subjects) (χ2 = 0.47, P > .10). Age of onset of depression did not differ between comorbid (mean = 30.48, SD = 9.01) and regional subjects (mean = 28.13, SD = 10.51) (t = −1.05, P > .10). Current rates of major depressive disorder were low and did not differ between comorbid (2.6 percent) and regional (4.0 percent) subjects (χ2 = 0.16, P > .10). Consistent with the pattern 168
of psychiatric histories assessed by clinical interviews, health history reports of specific physical symptoms that are likely to be a function of somatization rather than a major medical condition were generally higher in the comorbid than regional subgroups (Table 4). Of the 18 somatization-related symptoms explored, comorbid subjects were significantly more likely than regional subjects to indicate that they had ever had 13 of these complaints (for a period of six or more months); differences on the
The rate of the lifetime history of major depressive disorder was significantly higher in comorbid subjects than regional subjects.
balance of these symptoms were in the predicted direction, with somewhat higher endorsement by comorbid subjects. Health-related behaviors. Health-related behaviors did not differ significantly between groups. Comorbid subjects had a slight tendency to have smoked daily for a month or more at some point (65.8 percent) compared with regional subjects (50.8 percent), but these differences were not significant (χ2 = 2.63, P = .10). Daily use of caffeinated beverages did not differ between groups (79.0 percent of comor-
bid vs. 86.3 percent of regional subjects, χ2 = 1.20, P > .10). The average frequency of visits to a health professional were significantly higher for comorbid subjects (mean = 5.03, SD = 1.33) than regional subjects (mean = 4.00, SD = 1.46) (t = −4.08, P < .0001, where 1 = rarely or never, to 6 = once a month or more). Thus, comorbid subjects averaged from seven to 11 health-related visits per year, where regional subjects averaged three to six visits per year. Current physical health ratings were significantly poorer for comorbid subjects (mean = 2.71, SD = 0.96) than for regional subjects (mean = 2.11, SD = 0.77) (t = −3.56, P < .001, where 1 = excellent and 5 = very poor). The average number of medications used in the past month significantly differed for comorbid (mean = 4.87, SD = 2.82) and regional (mean = 3.20, SD = 2.44) subjects (t = −3.55, P < .001). DISCUSSION
Patterns of myofascial face pain/fibromyalgia comorbidity. This investigation compared two subgroups of patients who sought treatment for MFP. During a health history interview conducted an average of seven years later, nearly onefourth of these patients indicated that they also had a history of FM. For the “comorbid” patients with MFP and a self-diagnosis of FM, onsets of FM and MFP most often were reported to occur within the same year. If they did not, the facial pain problem most often predated the widespread one. This is inconsistent with a study of patients with FM who also had
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COVER STORY comorbid MFP.34 Two-thirds of the comorbid patients in that study reported onset of general pain first. It is possible that recall might be affected by treatment setting; our patients were recruited after having sought MFP treatment, while the other study’s patients were recruited in the context of FM treatment. Psychiatric and psychosocial factors associated with comorbid fibromyalgia. Our finding of higher rates of psychiatric disorder among those with comorbid FM than those with MFP differs from that of an earlier investigation25 in which the researchers found no significant group differences in psychological profile. However, sample sizes in the earlier study were small and statistical power was low. Moreover, although differences in the earlier study were not statistically significant, symptom scores were directionally higher in the FM group on all six psychological scales used. While elevated rates of psychiatric disorder in FM can be interpreted from several different perspectives,35 the hypothesis that elevated rates of psychiatric disorder in FM are an artifact of examining an unrepresentative, treatmentseeking sample (in which those with psychiatric disorders are overrepresented) is not a tenable explanation here. This is because both MFP and FM subjects were drawn from the same treatment-seeking filter. It may be noted that, in this study, current major depression rates in MFP were low relative to lifetime rates of major depression. This is likely the result of two factors. First, we explicitly oversampled MFP cases with a history of major
depression for other study purposes (see Methods). Since this oversampling was not differential for those who had comorbid FM compared with those who had MFP alone, this does not bias between-group comparisons but makes interpretation of the proportion of current-tolifetime major depression invalid. Second, as nearly onethird of the study subjects described their MFP as being in remission, rates of current depression may be lower in this sample than in a sample of active patients with MFP who are depressed secondary to their pain. Those with comorbid FM also reported having experienced many more facial pain symptoms at the time of retrospective health histories, even though those higher symptom rates were not detected at the time of MFP examination. At the time the retrospective health history reports were collected, comorbid subjects more often recalled having experienced extended periods of somatization-related symptoms. Both the discrepancy between examination and recalled symptoms of facial pain and the higher rates of somatization-related symptoms in the FM group may be a function of hypervigilance among patients with FM, in which an unusual degree of attention is paid to external and internal noxious sensations.36,37 Alternately, these reports may be secondary to the higher lifetime rates of major depressive disorder that we detected in the comorbid patient group, leading to biased recall38 of earlier symptoms. The elevated rates of psychiatric and psychosocial factors in patients with MFP having
symptoms of comorbid FM is generally consistent with a wide range of studies22,24,25 whose findings indicated more psychiatric and psychosocial impairment among patients with FM than patients with MFP. Whether those seeking MFP treatment who also have FM differ psychosocially from patients seeking FM treatment in rheumatology settings cannot be addressed here, as it would require accrual of a sample of patients with FM from a rheumatology practice. Research limitations. Our study based assessment of FM status on patients’ self-report. The question inevitably arises about the validity of the selfreport diagnosis of FM and how this method might have affected our conclusions. Although the self-diagnosis of FM was made without the benefit of a physical examination, the 21 percent rate of selfassessed current FM among active patients with MFP—not detailed previously—is consistent with two other studies using examination for diagnosis of FM; one22 reported FM that met ACR-criteria in 18 percent of patients with MFP, and the other 21 reported that between 13 and 20 percent of a mixed group of facial pain patients with no prior rheumatic disorder diagnoses met some or all criteria for FM. Although the current research data do not allow for direct testing of the extent to which our self-diagnosis method corresponds with more standardized methods13 of assessing FM, other epidemiologic data suggest that self-report of widespread pain corresponds well (that is, positive predictive values of 70 percent or higher)
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COVER STORY with the standard clinical diagnosis of FM, especially among women.39 In addition, in this study, we have shown that pain in the back of the neck and shoulder on examination was more frequent among those who self-reported a history of FM. These comparisons lend validity to self-reports of FM used in this study. If self-diagnosis of FM contains random error, it is likely to have led to an underestimation of the magnitude of the relationship between FM/MFP comorbidity and a poor clinical course of MFP. Nevertheless, future researchers attempting replication of our findings would be encouraged to use state-of-theart FM diagnostic methods.13 Clinical implications. At the time of treatment for facial pain, MFP symptoms were similar among all subjects, whether they had comorbid widespread or only regional MFP complaints. By themselves, patterns of MFP signs and symptoms are unlikely to provide clues to the likelihood of a patient’s having comorbid FM. However, FM-related symptoms were detected at the time of facial pain treatment more often among those who had a later self-diagnosis of FM. This suggests that the clinician who sees a patient seeking treatment for MFP would be well-advised to ascertain the presence of symptoms related to FM. The screening for FM among patients seeking treatment for MFP is especially important, as course and outcome are likely to be different in patients with solely a regional vs. a widespread myofascial disorder. This study found that patients who had MFP and comorbid self-assessed FM were less likely to say that their facial pain symptoms were 170
gone at the time of follow-up health history assessment. Comorbid patients recalled that their MFP problem more often interfered with social functioning and that the severity of pain was higher than among those who did not report having FM. The impact and prevalence of comorbid FM on MFP is likely to be greatest in tertiary care settings, in which patients with more chronic MFP are likely to be seen. The fact that we did not employ standardized FM diagnostic methods is clearly a research limitation. However, the self-report method we used may lend itself better to clinical application. Given the constraints of routine dental practice, it is unreasonable to expect the clinician to conduct a full diagnostic assessment of FM for all patients with MFP. Screening for FM, by asking patients with MFP about their history of widespread pain, is a manageable task in most clinical settings. In addition, a patient’s report of neck and shoulder pain should raise the dentist’s index of suspicion about the possibility of FM. Our finding that MFP comorbid with FM is more recalcitrant to treatment than MFP alone is important. It confirms the observations made in a recent study34 of patients with FM, 39 of whom had comorbid MFP. Among the 75 percent of patients with comorbid MFP and FM in that study who sought treatment, all indicated that their MFP treatment—typically oral appliances—was ineffective. Given these data and other data questioning the efficacy of oral appliances40,41 in treating MFP, the dentist is uniquely qualified to advise the
patient with FM/MFP about the devices’ potentially limited use. Although our study was not designed specifically to test the differential efficacy of particular MFP treatments for those with comorbid widespread vs. regional MFP, such studies are clearly needed. As we await more research explicating the customization of MFP treatment for comorbid widespread vs. regional MFP, what treatment recommendations can be made? If the patient’s reported symptoms suggest that he or she may have FM, referral to a rheumatologist for FM diagnostic assessment is recommended. However, this does not mean that dentists should abdicate their role in treatment of MFP, as “physicians have relegated the treatment of chronic musculoskeletal facial pain to the dental realm.”16(p.477) Low-dose tricyclic antidepressants, exercise and intramuscular injections—treatments advocated for both FM and MFP16—may be uniquely indicated for treatment of MFP in those who have comorbid FM. These treatments may be indicated particularly for patients in whom more conservative treatments, such as vapocoolant sprays and analgesics, are not effective. CONCLUSION
A retrospective study such as the one described here cannot firmly address issues surrounding similar or different pathogenesis of FM vs. MFP. Nor can it evaluate the plausibility of different explanatory models for the association between FM and MFP.42 Our data suggest the possibility that MFP secondary to FM is a different clinical entity than MFP secondary to
JADA, Vol. 131, February 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.
COVER STORY other causes. Other studies will be needed to confirm this possibility. Our findings, however, are clinically significant in that they show that the course of, outcome of and disability associated with MFP are influenced by whether MFP is accompanied by symptoms of FM. Thus, it is recommended that symptoms of FM be assessed among patients seeking treatment of a regional myofascial problem such as MFP. ■ Dr. Raphael is an associate professor, New Jersey Medical School, Department of Psychiatry, and New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, 30 Bergen St., ADMC 14, Newark, N.J. 07107. Address reprint requests to Dr. Raphael. Dr. Marbach is a professor, New Jersey Medical School, Department of Psychiatry, and Robert and Susan Carmel professor in algesiology, New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, Newark. Dr. Klausner is an instructor, New Jersey Dental School, Department of Oral Pathology, Biology and Diagnostic Sciences, University of Medicine and Dentistry of New Jersey, Newark. He also is in private practice in Boston. This study was supported by National Institute of Dental and Craniofacial Research grants DE05989 and DE11714, as well as grants from the J. Aron Charitable Foundation and the Revlon Foundation. 1. Greene CS, Laskin DM. Long-term evaluation of treatment for myofascial pain-dysfunction syndrome: a comparative analysis. JADA 1983;107(12):235-8. 2. Randolph CS, Greene CS, Moretti R, Forbes D, Perry HT. Conservative management of temporomandibular disorders: a posttreatment comparison between patients from a university clinic and from private practice. Am J Orthod Dentofacial Orthop 1990;98(1):77-82. 3. Wedel A, Carlsson GE. A four-year follow-up, by means of questionnaire, of patients with functional disturbances of the masticatory system. J Oral Rehabil 1986;13(2):105-13. 4. Ohrbach R, Dworkin SF. Five-year outcomes in TMD: relationship of changes in pain to changes in physical and psychological variables. Pain 1998;74(2-3):315-26. 5. Drangsholt M, LeResche L. Temporomandibular disorder pain. In: Crombie IK, Croft PR, Linton SJ, LeResche L, Von Korff, M, eds. Epidemiology of pain: A report of the Task Force on Epidemiology of the International Association for the Study of Pain. Seattle: IASP Press; 1999: 203-34. 6. Raphael KG, Marbach JJ. A year of chronic
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