Journal of Oral & Facial Pain and Headache, 02/2009

This article presents a comprehensive review of the topic of placebos, with a special focus on placebo analgesia. It includes a discussion of how placebos work (the placebo effect) and how patients react to them (the placebo response). A literature search was performed to identify relevant literature and publications related to the topic, and a qualitative assessment of papers was undertaken based on accepted rules for scientific evidence. The major finding from this review was that concepts about placebo effects and responses have changed dramatically over the years, especially in more recent years. This has occurred primarily as a result of more sophisticated experimental protocols using placebos in clinical studies of patients in pain, as well as various studies involving normal subjects. Our understanding of the biological and psychological mechanisms underlying placebo effects has expanded significantly due to recent developments in the technology of brain imaging. Based on findings from brain-imaging analyses, we now know that placebo analgesia is definitely a real (ie, biologically measurable) phenomenon. It can be pharmacologically blocked and behaviorally enhanced, and these responses have been demonstrated to be similar to those elicited by administration of "real" analgesic substances. Psychological mechanisms involved in placebo analgesia include expectancy, meaning response, and classical conditioning. This article concludes with an emphasis on understanding therapeutic responses to various treatments for temporomandibular disorders (TMD). Acupuncture and splint therapy can be good examples of powerful placebos in the field of TMD, and both of these are discussed in detail. Present knowledge suggests that every treatment for pain contains a placebo component, which sometimes is as powerful as the so-called "active" counterpart. While the deceptive use of placebos must be considered unethical, every health provider who is treating pain patients must be aware of this important phenomenon in order to harness its huge potential. Palabras clave: acupuncture, brain imaging, expectancy, oral splints, placebo effect, TMD

Aims: To estimate the diagnostic accuracy of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) clinical examination and of the dynamic/static tests for the recognition of TMD pain. Since the diagnosis of TMD pain is especially complicated in persistent orofacial pain patients, the test outcomes in persistent TMD pain patients were contrasted to those in two control groups: a group of persistent dental pain patients and a group of pain-free subjects. Methods: In 125 persistent TMD pain patients, 88 persistent dental pain patients, and 121 pain-free subjects, a blind and standardized clinical examination was performed. Results: For the RDC/TMD, sensitivity (88%) was high and specificity was low (pain-free group: 71%; dental pain group: 45%). For the dynamic/static tests, sensitivity was 65% and specificities were 91% and 84%, respectively. Comparing the outcomes of the two examinations showed higher positive likelihood ratios for dynamic/static tests (P .001), and lower negative likelihood ratios for the RDC/TMD examination (P .01). Conclusion: For the confirmation of a suspicion of TMD pain, it is better to rely on positive dynamic/static tests. To confirm the absence of TMD pain, it is better to rely on a negative RDC/TMD examination. Palabras clave: dental pain, diagnostic accuracy, dynamic/static tests, RDC, TMD

Aims: To evaluate the impact of temporomandibular disorder (TMD) pain by age and gender in adolescents, with assessments of this impact specifically on school absence, medication consumption, perceived need for treatment, jaw function limitation, depressive symptoms scores and somatic complaints, and graded chronic pain scale. Methods: In a population-based sample, a mailed questionnaire was sent to 350 patients with self-reported TMD pain (group 1) and 350 healthy age- and sex-matched individuals (group 2) aged 12 to 19 years 2 to 4 weeks after their annual dental examination. The groups were divided into younger (age 12 to 15) and older (age 16 to 19) groups. Descriptive statistics and 95% confidence intervals were used, and chi-square and t-tests were calculated for analyzing group differences. Odds ratios were estimated using logistic regression. Results: As expected, groups 1 and 2 differed significantly in most variables related to psychosocial and behavioral factors. For adolescents reporting TMD pain once a week or more, no gender or age differences in pain intensity were seen. Jaw function limitation, depressive symptoms scores, somatic complaints, graded chronic pain, and perceived need for TMD treatment were all significantly higher in girls than in boys. Older girls reported higher analgesic consumption and school absences than older boys. Conclusion: Girls reporting TMD pain had significantly greater impact on behavioral and psychosocial factors than boys. Almost one third of older girls, compared to one out of 10 older boys, reported school absences and analgesic consumption because of their TMD pain. Palabras clave: adolescence, gender, jaw function, psychosocial status, TMD pain

Aim: To describe evidence for a relationship between diagnoses and findings of clinical examination and diagnoses and findings of magnetic resonance imaging (MRI) examination for degenerative and inflammatory temporomandibular joint diseases. Methods: PubMed and the Cochrane Library were searched using specific indexing terms and reference lists were hand-searched. Included publications satisfied pre-established criteria. Primary studies were interpreted using a modification of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Results: The literature search yielded 219 titles and abstracts. Eighty-two studies were selected and read in full-text. After data extraction and interpretation with the QUADAS tool, 23 studies remained. There was a vast heterogeneity in study design, clinical examination methods, and diagnostic criteria. No clear evidence was found for a relationship between clinical and MRI diagnoses and findings. Several studies reported a relationship between clinical pain and internal derangements diagnosed with MRI, but the calculated odds ratio (OR) for this relationship was generally low (1.54-2.04). ORs for the relationship between pain and disc displacement without reduction (4.82) or between crepitation and disc displacement without reduction (3.71) were higher. Conclusion: This review reveals a need for studies with improved quality in reporting of samples, examination techniques, findings, and definitions and rationales for cutoffs, categories, and diagnoses. We recommend that standardized protocols such as the Research Diagnostic Criteria for temporomandibular disorders (RDC/TMD) and the Standards for Reporting of Diagnostic Accuracy (STARD) statement be implemented in future studies. Palabras clave: clinical examination, internal derangement, magnetic resonance imaging, pain, temporomandibular disorders

Aims: To use PRISM (Pictorial Representation of Illness and Self Measure), a visual instrument that has recently been developed and validated to assess suffering in patients with chronic physical illness, in orofacial pain patients and test for associations of PRISM with established assessment tools for pain, affective symptoms, and sleep. Of particular interest was the utility of PRISM as a screening tool for severely suffering patients. Methods: One hundred and two orofacial pain patients recruited from a specialized outpatient service completed a questionnaire-based survey, including established assessment tools: the Visual Analog Scale (VAS), Graded Chronic Pain Scale (GCPS), the Hospital Anxiety and Depression Scale (HADS), and the Insomnia Severity Index (ISI), as well as a paper and pencil version of PRISM. Results: Of the 102 patients who submitted the clinical questionnaire, 74 performed the PRISM-test (response rate: 72%). PRISM scores correlated strongly with all subscores of pain (measured by GCPS) and sleep (measured by ISI). Further, a trend was observed in the correlation with affective symptoms measured by the HADS. PRISM could readily detect patients with high, pain-related suffering. Conclusion: These data add support to the hypothesis that the PRISM task in its paper and pencil version is measuring the burden of suffering. The clinical utility of this simple graphic tool therefore lies in its potential to alert clinicians to a high burden of suffering and thus it may help to identify orofacial pain patients who may benefit from more comprehensive assessment and treatment. Prospective studies are needed to clarify this claim. Palabras clave: anxiety, depression, orofacial pain, PRISM, sleep, suffering

Aims: To investigate the association of sense of coherence (SOC) with clinical findings of temporomandibular disorders (TMD) among 30- to 64-year-old subjects. Methods: A nationally representative health examination survey called the Health 2000 Survey was carried out from 2000 to 2001. The data for this study were obtained from 4,859 subjects aged 30 to 64 years who had participated in an interview, been clinically examined, and returned a self-administered questionnaire. The questionnaire included a SOC scale which was a 12-item version of the SOC-13 scale. Based on a clinical examination for TMD, the following variables were formed: maximum interincisal distance 40 mm, clicking, crepitation, pain in the temporomandibular joints (TMJs), and pain in the masticatory muscles. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models. Results: Subjects with low SOC had higher odds to have distinct TMD findings, especially masticatory muscle pain, than those with high SOC. After adjustment for confounders, those with low SOC had more than twofold odds to have masticatory muscle pain (in at least one painful site) compared to those with high SOC (OR 2.2, 95% CI 1.4-3.6). Low SOC was also associated with TMJ pain on palpation (OR 3.2, 95% CI 1.5-6.6). Conclusion: Low SOC associates with myogenous TMD findings. SOC as a psychosocial aspect has a role in the background of TMD. Palabras clave: masticatory muscle pain, psychosocial, sense of coherence, temporomandibular disorders

Aims: To summarize literature data about the role of psychosocial factors in the etiology of bruxism. Methods: A systematic search in the National Library of Medicine's PubMed Database was performed to identify all peer-reviewed papers in the English literature dealing with the bruxism-psychosocial factors relationship. All studies assessing the psychosocial traits of bruxers (by using questionnaires, interviews, and instrumental and laboratory exams) and reviews discussing the contribution of those factors to the etiology of bruxism were included in this review. Results: A total of 45 relevant papers (including eight reviews) were retrieved with a search strategy combining the term "bruxism" with the words stress, anxiety, depression, psychosocial and psychological factors. The majority of data about the association between psychosocial disorders and bruxism came from studies adopting a clinical and/or self-report diagnosis of bruxism. These studies showed some association of bruxism with anxiety, stress sensitivity, depression and other personological characteristics, apparently in contrast with sleep laboratory investigations. A plausible hypothesis is that clinical studies are more suitable to detect awake bruxism (clenching type), while polysomnographic studies focused only on sleep bruxism (grinding type). Conclusion: Wake clenching seems to be associated with psychosocial factors and a number of psychopathological symptoms, while there is no evidence to relate sleep bruxism with psychosocial disorders. Future research should be directed toward the achievement of a better distinction between the two forms of bruxism in order to facilitate the design of experimental studies on this topic. Palabras clave: anxiety, bruxism, depression, etiology, psychosocial factors, stress

Aims: To evaluate possible effects of the intracerebroventricular (icv) injection of either O-Tricyclo [5.2.1.02,6] dec-9-yl dithiocarbonate potassium salt (D609), a potent antioxidant and inhibitor of phosphatidylcholine specific phospholipase C (PtdCho-PLC) and acid sphingomyelinase (ASMase), or the spin trap/free radical scavenger N-tert-Butyl-a-phenylnitrone (PBN), on mechanical allodynia induced by facial carrageenan injection in mice. Methods: Balb/c mice received icv injection of D609/PBN plus facial carrageenan injection, and the number of face wash strokes to von Frey hair mechanical stimulation of the maxillary skin was quantified. PtdCho-PLC and ASMase activities were also assayed in the brainstem, thalamus, and somatosensory cortex. Results: Mice that received the icv injection of 10 nmol D609 plus facial carrageenan injection showed significantly fewer face wash strokes evoked by von Frey hair stimulation (indicating reduced mechanical allodynia) at 1 and 3 days post-injection, compared to mice that received icv injection of isotonic saline plus facial carrageenan injection. Mice that received icv injection of 1.13 µmol PBN plus facial carrageenan injection likewise showed significantly fewer face wash strokes after facial carrageenan injection, compared to isotonic saline-injected plus carrageenan-injected controls. D609 injection also resulted in significantly reduced ASMase activity in the brainstem, thalamus, and somatosensory cortex 3 days after injection, compared to controls. Conclusion: The icv injections of D609 and PBN were effective in reducing mechanical allodynia after facial carrageenan injection-induced pain. Together, the results point to a possible role of central nervous system sphingolipids and/or free radicals in orofacial pain. Palabras clave: acid sphingomyelinase, free radicals, mechanical allodynia, orofacial pain, phosphatidylcholine specific phospholipase C, reactive oxygen species, ROS

Temporomandibular disorders (TMD) is a term reflecting chronic, painful, craniofacial conditions usually of unclear etiology with impaired jaw function. Human immunodeficiency virus (HIV)-infected patients often report chronic pain and pathologies targeting body joints during retroviral therapy. Although both conditions may share similar secondary disorders, no conclusive cause-effect relationship has been found linking the TMD to the HIV-antiviral treatment. This report describes a case of TMD associated with HIV infection during active retroviral therapy. Clinicians should be aware that treatment of an HIV-infected patient with TMD requires an interdisciplinary team approach. Palabras clave: human immunodeficiency virus, infection, pain, retroviral therapy, temporomandibular disorders, temporomandibular joint