Journal of Oral & Facial Pain and Headache, 04/2018

Aims: To determine the prevalence of the signs and symptoms of temporomandibular disorders (TMD) and associated variables over the past two decades in samples of Spanish adults and seniors. Methods: Data from Spanish national oral health surveys from the last two decades (1993, 2000, 2005, 2010, and 2015) were analyzed from a total of 2,602 adults (35-44 years of age) and 2,529 seniors (65-74 years of age). All surveys were carried out using similar methods (according to World Health Organization standards) for determining prosthetic, dental, and periodontal statuses. For TMD (assessed only among the adults and seniors), inspection/palpation of the temporomandibular joint and masticatory muscles was used to evaluate three different domains: joint sounds; pain-related conditions (joints/muscles); and range of jaw motion. Risk factors were identified using bivariate analysis and were confirmed after a multivariate logistic regression analysis for predicting the presence of TMD pain/dysfunction. Results: Despite the clear improvement in oral health status observed over the entire study period (1993-2015), the prevalence of temporomandibular pain and dysfunction increased over time in both adults and seniors (the odds ratio [OR] 95% confidence interval [CI] for the entire study period increased, to 2.39 to 4.29). The odds of women and those living in rural areas developing TMD were higher than for men (OR = 1.85; 95% CI 1.52 to 2.25; P < .001) and for those living in urban areas (OR = 1.55; 95% CI 1.24 to 1.94; P < .001), respectively; however, the prevalence of joint sounds (with no pain or functional restrictions) appeared to be stable throughout the study period at around 14%. Conclusion: The prevalence of painful or dysfunctional TMD has significantly increased in the last 22 years in Spain. Besides the time factor, other major predictors of TMD were gender and place of residence. Keywords: epidemiology, functional limitation, pain, risk factors, secular changes, temporomandibular disorders

Aims: To determine whether the facial side of an overerupted third molar and/ or the side exhibiting symptoms of temporomandibular disorders (TMD) has an association with the bilateral distribution of occlusal contact number, occlusal force, or surface electromyographic (SEMG) activity of the anterior temporalis (TA) and masseter muscles. Methods: Nineteen patients with unilateral TMD symptoms and one overerupted mandibular third molar were enrolled. Occlusal contacts and the SEMG activity of the anterior temporalis and masseter muscles were recorded simultaneously during maximal voluntary clenching (MVC) in the intercuspal position (ICP-MVC) and in the protrusive edge-to-edge position (Pro-MVC). The associations between the side of overeruption/TMD symptoms and the Δvalues of the differences between the right- and left-side values for the number of occlusal contacts, sectional force value (defined as the ratio of the anterior or posterior sectional arch bite force of the right or left side to the total arch force {SFV]), and SEMG activity of the temporalis and masseter muscles were analyzed. Results: The overeruption side (P < .050), but not the symptomatic side (P > .050), showed an association with the Δvalues, with higher SFVs of the posterior arch and lower values for temporalis SEMG activity in the 100%, 75%, and 50% protrusive clenching positions and larger numbers of occlusal contacts in the posterior arch in the 100% and 75% protrusive clenching positions than the non-overeruption side. Conclusion: The pattern of occlusion, but not TMD symptoms, had an association with the number and distribution of the occlusal contacts, occlusal force, and temporalis SEMG activity. Keywords: bite force, electromyography, jaw-closing muscle, occlusal contact, third molar overeruption

Aims: To analyze in a population from Argentina the variation of three genes involved in the control of pain pathways-two genes that code for opioid receptors (OPRM1 and OPRK1) and COMT, which codes for an important enzyme in the control of neurotransmission-and to evaluate the associations of these genes with oral pain and the need for analgesics in the population under study. Methods: A total of 134 volunteer donors from the city of Resistencia and 27 donors from the Wichí community for comparison were analyzed for 13 single nucelotide polymorphisms (SNPs) and 1 insertion/deletion (Indel) localized in the three genes using polymerase chain reaction-restriction fragment length polymorphism or standard PCR and electrophoresis. All 134 individuals from Resistencia provided biologic samples for DNA analysis, and a subset (n = 81) agreed to answer a questionnaire for an association analysis. Statistical tests for a possible association between genetic variation and self-reported ethnic origin, oral pain, and need for analgesic drugs were performed. Results: Significant differences were found when the study population was compared to populations from other continents, as well as between the two studied populations (P < .05). A positive association was suggested for the COMT gene from Resistencia with both oral pain intensity and analgesic requirements. Conclusion: The admixture process that occurred in the past of Resistencia probably contributed to a genetic differentiation in this population, and this genetic variation might influence phenotypic expressions of pain perception and analgesic requirements. Keywords: admixed population, pain genetics, pain perception, single nucleotide polymorphisms

Aims: To investigate whether a dose-response relationship exists between the intensity of pain-related temporomandibular disorders (TMDs) and the amount of self-reported bruxism activities in a group of TMD pain patients. Methods: A total of 768 patients referred to a specialized clinic for complaints of orofacial pain and dysfunction were initially enrolled in the study. Of these patients, 293 who were diagnosed with at least one type of pain-related TMD according to the Diagnostic Criteria for Temporomandibular Disorders were selected. The questionnaire-based reports of TMD pain intensity, as assessed by an 11-point numeric rating scale (NRS), were subsequently compared to the reports of sleep bruxism (single question; 5-point Likert scale) and awake bruxism (mean score of six questions; 5-point Likert scale). Spearman correlations were used to assess associations, and possible confounding effects of depression, somatic symptoms, and anxiety were taken into account. Results: Spearman correlation tests provided no significant correlation between the amount of self-reported sleep bruxism and TMD pain intensity. On the other hand, the amount of awake bruxism was positively correlated with the intensity of TMD pain; however, the latter correlation was lost when the model was controlled for the effects of depression. Conclusion: The assumption that there is a dose-response gradient association between bruxism and TMD pain, reflected in more bruxism leading to more overloading and thus to more pain, could not be justified. Keywords: bruxism, confounding, dose-response relationship, pain-related temporomandibular disorders, psychological factors

Aims: To test whether women with temporomandibular disorder (TMD)-related pain showed higher psychosocial scores and higher awake- and sleep-time jaw muscle activities (characterized by duty factors) compared to pain-free controls and whether psychosocial scores and the jaw muscle duty factors were associated. Methods: Subjects gave informed consent to participate. The Diagnostic Criteria for TMD (DC/TMD) were used for diagnosis of TMD pain, and 31 and 36 women were included in the TMD-related pain and control groups, respectively. DC/TMD Axis II instruments were used to determine psychosocial scores. Subjects self-recorded masseter and anterior temporalis electromyography (EMG) over 3 days and 3 nights. The duty factor (time of muscle activity/total recording time [%]) was quantified using subject-specific EMG/bite-force calibration via data recorded in the laboratory. Group differences (α = .05) were assessed for psychosocial scores and duty factors using chisquare and two-sample t tests. Linear regression assessed whether psychosocial scores were associated with duty factors. Results: Average duty factors were ≤ 2.4% for awake and sleep times in both muscles, and between-group comparisons showed no significant differences. For physical symptom scores, there were significantly fewer TMD-related pain subjects in the normal category and significantly more in the moderate-severe category (all P < .01) compared to controls. Subjects with elevated compared to normal psychosocial scores showed significantly higher jaw muscle duty factors by ≥ 1.5-fold. Conclusion: A significantly larger proportion of TMD-related pain subjects compared to control subjects had moderate-severe physical symptom scores. Awake- and sleep-time jaw muscle duty factors were not different between groups and were generally low among all subjects. Additionally, higher than normal psychosocial scores were associated with significantly more low-magnitude jaw muscle activity. Keywords: bruxism, EMG, jaw muscle, pain, psychosocial factors, TMD

Aims: To culturally adapt the Craniofacial Pain and Disability Inventory (CF-PDI) for a Brazilian population and to assess its psychometric properties, including internal consistency, reliability, and construct and structural validity. Methods: A total of 100 female and male TMD patients with temporomandibular disorders (TMD), with or without headaches, were included. Participants were assessed based on the Research Diagnostic Criteria for TMD and the International Headache Society criteria. For statistical analyses, intraclass correlation coefficient (ICC) was used for assessing reliability (test-retest), Cronbach's alpha for internal consistency, Pearson rank correlation for construct validity, and confirmatory factor analysis (CFA) for structural validity. Results: The CFA provided the following three factors/domains for the Brazilian CF-PDI (CF-PDI/Br): (1) functional and psychosocial limitation; (2) pain; and (3) frequency of comorbidities. Scores for test-retest reliability and internal consistency in each domain were acceptable (ICC > 0.9; Cronbach's α > 0.77). Correlations between CF-PDI scores and jaw functional limitation, pain-related disability, pain catastrophizing, depression, neck pain-related disability, and kinesiophobia scores were confirmed in 89% (50/56) of the comparisons. Conclusion: The CF-PDI/Br with three factors had sound psychometric properties. Therefore, the Brazilian Portuguese version can be used in clinical settings and for research purposes. Keywords: construct validity, cross-cultural validity, internal consistency, structural validity, temporomandibular disorders, test-retest reliability

Aims: To investigate the test-retest reliability of mechanical sensitivity mapping in the masseter and temporomandibular joint (TMJ) regions between sessions, days, and examiners with a fixed and standardized pressure stimulus, as well as to compare mechanical sensitivity between sides and sites. Methods: A total of 20 healthy young volunteers participated. Pressure stimulation was applied to 15 sites in the masseter region with a Palpeter device of 1.0-kg force and to 9 sites in the TMJ region with a Palpeter of 0.5-kg force. All participants were tested twice in two separate sessions on the same day by Examiner 1 with an interval of 3 hours between tests. After 1 week, the protocol was repeated in the same manner in two separate sessions by Examiner 1 and Examiner 2 (one session each). Results: Analysis of variance (ANOVA) of numeric rating scale (NRS) scores and center of gravity (COG) values in both regions showed no significant main effects of examiner, day, or session (P ≥ .167). The test-retest reliability of data implied excellent agreement (intra-class correlation coefficients all > 0.75) between different examiners, days, and sessions. In addition, the ANOVA of the mean NRS scores in both regions showed significant main effects of site (P = .001). Conclusion: This feasible and reliable technique may provide a new tool for comprehensive evaluation of mechanical allodynia and hyperalgesia in the orofacial region, which are common features related to temporomandibular disorders and other chronic craniofacial pain conditions. Keywords: mechanical sensitivity mapping, numeric rating scale, palpometer, reliability, trigeminal pain physiology

Aims: To investigate whether pain catastrophizing has not only direct effects as a predictor of pain-related interference but also indirect effects as a mediator in the relationship between psychological distress and pain interference and to examine the mediating roles of subtypes of catastrophizing (magnification, rumination, and helplessness) between psychological distress and interference. Methods: This retrospective study included 815 patients with orofacial pain aged 18 to 81 years. All participants completed a set of self-administered questionnaires concerning pain interference (Brief Pain Inventory), psychological distress (Symptom Checklist-90-Revised), and pain catastrophizing (Pain Catastrophizing Scale) at the first consultation. The associations between these three variables were calculated using mediation path analysis. Results: Pain catastrophizing predicted pain interference. In addition, 34% of the variance in pain interference attributable to psychological distress was mediated by catastrophizing when controlling for pain duration and severity. The greatest portion of the mediating effect of catastrophizing was attributable to the helplessness component. Conclusion: Within the limitations of cross-sectional studies, this study demonstrated that pain catastrophizing mediates the effects of psychological distress on pain interference in patients with orofacial pain. Most of the mediating effects were attributable to the helplessness component of pain catastrophizing. Cognitive behavioral therapy targeting pain catastrophizing, specifically helplessness, could potentially reduce pain-related disability in orofacial pain patients. Keywords: mediation analysis, orofacial pain, pain catastrophizing, pain interference, psychological distress

Aims: To investigate whether glutamate-evoked pain in the masseter region differs between three different depths of injection, targeting subcutaneous, muscle, and bone tissues. Methods: A total of 16 healthy volunteers participated and, in a randomized order, received injections of glutamate (1.0 M, 0.2 mL) and isotonic saline (0.9%, 0.2 mL) in the masseter region that targeted subcutaneous, intramuscular, and bone surface tissues. Following injection, pain intensity was measured using electronic visual analog scale (eVAS) and numeric rating scale (NRS) scores of unpleasantness, tiredness, tension, soreness, and stiffness. Pressure pain sensitivity (PPS), pain drawing areas, and McGill Pain Questionnaire (MPQ) scores were also assessed. Repeated-measures analysis of variance, McNemar test, and Tukey post hoc tests were used for statistical analyses. P < .05 was considered statistically significant. Results: Overall, subcutaneous injections induced significantly more unpleasantness and pain than intramuscular injections, and PPS scores evoked after glutamate injection at the surface of the bone were significantly higher than after intramuscular glutamate injection. Subcutaneous glutamate injections were more often described as "sharp" and "pinching." Conclusion: The subcutaneous injection was more painful and unpleasant than the intramuscular injection. The glutamate injection at the surface of the bone sensitized the deep pain tissues to pressure stimulation. Clinically, it may be difficult to differentiate between the source or site of pain originating from the masseter region, but the specific quality and word descriptors could assist in differential diagnosis. Keywords: bone surface, glutamate, myofascial pain, subcutaneous, temporomandibular disorders

Aims: To assess the modulatory effects of experimental psychological stress on the somatosensory evaluation of myofascial temporomandibular disorder (TMD) patients. Methods: A total of 20 women with myofascial TMD and 20 age-matched healthy women were assessed by means of a standardized battery of quantitative sensory testing. Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical pain threshold (MPT), wind-up ratio (WUR), and pressure pain threshold (PPT) were performed on the facial skin overlying the masseter muscle. The variables were measured in three sessions: before (baseline) and immediately after the Paced Auditory Serial Addition Task (PASAT) (stress) and then after a washout period of 20 to 30 minutes (poststress). Mixed analysis of variance (ANOVA) was applied to the data, and the significance level was set at P = .050. Results: A significant main effect of the experimental session on all thermal tests was found (ANOVA: F > 4.10, P < .017), where detection tests presented an increase in thresholds in the poststress session compared to baseline (CDT, P = .012; WDT, P = .040) and pain thresholds were reduced in the stress (CPT, P < .001; HPT, P = .001) and poststress sessions (CPT, P = .005; HPT, P = .006) compared to baseline. In addition, a significant main effect of the study group on all mechanical tests (MPT, WUR, and PPT) was found (ANOVA: F > 4.65, P < .037), where TMD patients were more sensitive than healthy volunteers. Conclusion: Acute mental stress conditioning can modulate thermal sensitivity of the skin overlying the masseter in myofascial TMD patients and healthy volunteers. Therefore, psychological stress should be considered in order to perform an unbiased somatosensory assessment of TMD patients.

Hemangiomas are benign vasoformative neoplasms or developmental conditions of endothelial origin. Synovial hemangiomas arise from a synovial lined surface within a joint space. This report describes a case of synovial hemangioma of the left temporomandibular joint (TMJ) in a 65-year-old male patient. Histologic examination confirmed the diagnosis of synovial hemangioma. This is a rare case series, as the only case of synovial hemangioma with TMJ localization previously described was reported in 1988. Keywords: TMJ hemangioma, TMJ neoplasm, synovial hemangioma

Cluster headache (CH) is a rare trigeminal autonomic cephalalgia. Although its pathophysiology is not entirely understood, the hypothalamus and trigeminal nociceptive and autonomic pathways seem to play a key role in its pathology. In the majority of cases, CH begins at a young age and affects mainly men. This article presents a case of a 76-year-old woman with CH that developed at the age of 74. This is one of the first documented reports of CH with such atypical features from an epidemiologic point of view. A possibility of symptomatic cluster-like headache (CLH) attributed to cerebrovascular disease in the patient is also discussed. Keywords: age at onset, cluster headache, primary headache, secondary headache, trigeminal autonomic cephalalgia

The great auricular nerve (GAN) is a sensory branch of the cervical plexus originating from the C2 and C3 nerve roots that innervates the external ear, mandibular angle, and parotid gland. Since idiopathic GAN neuralgia is a rare condition and branches of the GAN overlap with other cervical and cranial nerves, its diagnosis is challenging and can be confused with other facial neuralgias. This article describes the case of a 55-year-old woman with intractable unilateral periauricular and lateral head pain. No significant findings were found on cervical and brain imaging. At first, the patient was suspected to be suffering from trigeminal neuralgia or great occipital neuralgia; however, the symptoms persisted despite pharmacotherapy, cervical plexus and medial branch block, and repetitive transcranial magnetic stimulation. On the basis of an electrophysiologic examination, the patient was diagnosed as having GAN lesions. Pain subsided immediately after ultrasound-guided GAN block with local anesthetics and steroids. These findings indicate that electrophysiologic studies are helpful for accurately diagnosing patients with unclear pain in the periauricular and lateral head. Keywords: auricular pain, electrophysiologic study, facial pain, great auricular nerve, neuropathic pain