Journal of Oral & Facial Pain and Headache, 04/2019

Aims: To investigate the transverse dental and skeletal aspects of malocclusion in a sample of temporomandibular disorders (TMD) patients and to assess the correlations of these aspects with the signs and symptoms of TMD. Methods: A total of 150 TMD patients diagnosed according to the Diagnostic Criteria for TMD were divided into five groups: Group 1 (myalgia), Group 2 (disc displacement with reduction [DDWR]), Group 3 (disc displacement without reduction [DDWOR]), Group 4 (degenerative disorders), and Group 5 (subluxation). The transverse occlusion was assessed clinically, and any posterior crossbite present was recorded. Using cone beam computed tomography, several skeletal and dental transverse measurements were evaluated in each patient to diagnose the presence of skeletal posterior crossbite and possible facial and dental asymmetry. One-way analysis of variance was used to compare the means of more than two groups. Pearson correlation coefficient was used to assess the correlations of quantitative continuous variables. Significance level was considered at P .05. Results: Posterior crossbite was found in only 18% of the sample, while 28.7% of the subjects showed transverse skeletal crossbite. All skeletal and dental measurements evaluating symmetry showed no statistically significant differences between the groups except for the occlusal plane cant, which was significantly higher in Group 2 compared to Group 1. Dental and skeletal transverse discrepancies showed no correlation with TMD. Conclusions: Transverse malocclusion is not correlated with the signs and symptoms of TMD. Keywords: facial asymmetry, malocclusion, posterior crossbite, skeletal crossbite, temporomandibular disorders

Aims: To investigate the roles of autonomic regulation and psychologic condition in the development of tinnitus in patients with chronic temporomandibular disorders (TMD). Methods: In total, 55 participants (mean age 36.4 ± 12.6 years; 7 men, 48 women) were involved: 13 with no signs of painful TMD or tinnitus (CON), 15 with painful TMD without tinnitus (pTMD), and 27 with both painful TMD and tinnitus (TMDTIN). The Research Diagnostic Criteria for TMD and the Tinnitus Handicap Inventory (THI) were used to classify painful TMD and selfreported tinnitus, respectively. Measures of arterial heart rate (HR) and blood pressure (BP) were assessed at rest and in response to orthostatic challenges, cold-stress vasoconstriction, Valsalva maneuver, and psychologic stress. The sympathetic variables (BP responses to standing, cold stress, and psychologic stress) and parasympathetic variables (HR response to Valsalva maneuver [Valsalva ratio] and active standing [30:15 ratio]) were estimated. Results: Parasympathetic measures demonstrated significant differences between pTMD and TMDTIN. The period of pain duration showed significant positive correlations with BP variables during orthostatic challenges and/or cold stress in both pTMD and TMDTIN. THI scores showed significant positive correlations with results from the psychologic analysis. The range of motion of the mandible demonstrated a greater correlation with results from the psychologic analysis in TMDTIN compared to pTMD. Conclusion: Dysregulated psychophysiologic interactions may affect the development of tinnitus in patients with chronic TMD. Keywords: autonomic nervous system, central nervous system sensitization, comorbidity, temporomandibular disorders, tinnitus

Aims: To determine the effect of alterations in applied force on the two-point discrimination (TPD) threshold and to evaluate whether these effects were gender- or site-dependent. Methods: A total of 62 healthy adults were enrolled in the study and divided into two groups based on gender (men and women, n = 31 each). The TPD test was performed using a modified compass on the forehead, upper labium, and lower labium, and each site was tested with Semmes-Weinstein monofilaments (SWMs) of sizes 4.56, 5.07, and 5.46 that exerted bending forces of 6, 10, and 26 g, respectively. The differences in thresholds according to alterations in the applied forces were evaluated for different genders and sites. Results: Both gender groups showed a significant decrease in TPD thresholds with the 5.46-size monofilament than with the 4.56- or 5.07-size monofilaments. This decrease was more apparent on the forehead regardless of gender. Conclusion: These findings suggest that increased intensity of mechanical stimuli could increase tactile acuity as measured by the TPD test. Keywords: face, force, gender, spatial acuity, two-point discrimination

Aims: To better understand the experiences of individuals who must alter the types of food they eat because of having a chronic temporomandibular joint disorders (TMD) and the digestive issues that these alterations produce. Methods: Six participants answered open-ended questions during semi-structured interviews about their experiences with TMD-related changes in diet and digestion. These interviews, held face-to-face with the participants in a nonclinical environment, were recorded and transcribed. Interpretive phenomenology was used to arrange and analyze the narrative data collected. Results: The authors identified three common themes among the participants: (1) constipation and bloating; (2) loss of chewing function; and (3) weight change. For each of these themes, participants expressed physiologic and psychologic complications, which were largely unaddressed by their health care providers. Conclusion: These findings highlight the need for health care providers to establish nutritional guidelines for TMD individuals at risk of physiologic and psychologic comorbidities. Health care intervention programs to treat people living with chronic TMD pain and that provide nutritional guidance will help decrease medical crises and the need for expensive interventions and will better assist these patients. Keywords: digestion, experience, nutrition/diet/food, orofacial pain, temporomandibular disorders

Aims: To investigate whether an international consensus exists among TMD experts regarding indications, performance, follow-up, and effectiveness of jaw exercises. Methods: A questionnaire with 31 statements regarding jaw exercises was constructed. Fourteen international experts with some geographic dispersion were asked to participate in this Delphi study, and all accepted. The experts were asked to respond to the statements according to a 5-item verbal Likert scale that ranged from "strongly agree" to "strongly disagree." The experts could also leave free-text comments, which was encouraged. After the first round, the experts received a compilation of the other experts' earlier responses. Some statements were then rephrased and divided to clarify the essence of the statement. Subsequently, the experts were then asked to answer the questionnaire (32 statements) again for the second round. Consensus was set to 80% agreement or disagreement. Results: There is consensus among TMD experts that jaw exercises are effective and can be recommended to patients with myalgia in the jaw muscles, restricted mouth opening capacity due to hyperactivity in the jaw closing muscles, and disc displacement without reduction. The patients should always be instructed in an individualized jaw exercise program and also receive both verbal advice and written information about the treatment modality. Conclusion: This Delphi study showed that there is an international consensus among TMD experts that jaw exercises are an effective treatment and can be recommended to patients with TMD pain and disturbed jaw function. Keywords: Delphi technique, dentistry, jaw exercises, orofacial pain, physical treatment

Aims: To study the possible associations of various clinically assessed painful signs of temporomandibular disorders (TMD) with the presence of migraine using a large population-based dataset. Methods: The data were taken from the nationally representative Health 2000 Survey (BRIF8901). The sample consisted of 5,876 adults (age range 30 to 97 years, mean ± standard deviation 52.5 ± 14.8), 5,378 nonmigraineurs and 498 migraineurs. The study participants answered questions concerning migraine presence, migraine frequency, and migraine medication consumption during a home interview. They also underwent a clinical TMD examination. Results: Based on the multivariate regression models, painful muscular TMD, but not joint-related TMD, was associated with the presence of migraine (odds ratio [OR] = 1.58; 95% confidence interval [CI] = 1.23 to 2.04; P .01). Migraine with TMD was associated with increased migraine frequency (daily or a few attacks within a week) (OR = 1.93; 95% CI = 1.27 to 2.93; P .01) and higher migraine medication consumption (OR = 2.37; 95% CI = 1.43 to 3.92; P .01). Conclusion: According to the results of this study, muscle-related TMD pain is associated with the presence of migraine. Additionally, migraine along with painful TMD signs is associated with increased migraine frequency and migraine medication consumption. Keywords: headache medication, migraine, pain, temporomandibular disorders

Cluster headache (CH) is a primary headache disorder characterized by unilateral headache attacks lasting 15 to 180 minutes, occurring between two and eight times a day, and accompanied by autonomic symptoms ipsilateral to the pain. However, cases of symptomatic CH that occur secondary to an underlying structural pathology have also been reported in the literature. In this report, seven patients are presented who were admitted with signs of CH and diagnosed with acute rhinosinusitis depending on extensive clinical and radiologic examinations. Symptomatic CH, though rarely reported in the literature compared to CH, should be kept in mind in patients presenting with the first attack of CH. Moreover, in such patients, whether the pain becomes worse when bending forward and becomes sensitive on palpation should be questioned, and a radiologic work-up should be performed to rule out secondary causes such as rhinosinusitis. In the present cases, the resolution of CH attacks with acute sinusitis therapy confirmed the diagnosis. Keywords: cluster headache, inflammation, pain, rhinosinusitis

Aims: To test the hypotheses that, in comparison to control (isotonic saline), simultaneous noxious stimulation (hypertonic saline) of the masseter and anterior temporalis muscles would result in (1) reductions in amplitude and velocity of jaw movements during standardized open/close jaw movements and during free and standardized chewing and (2) changes in amplitude and velocity of jaw movements that relate to higher levels of negative mood or pain-related thoughts. Methods: Standardized open/close and free and standardized chewing were recorded in 15 asymptomatic participants in three blocks: block 1 (baseline), block 2 (during 5% hypertonic or 0.9% isotonic saline infusion into the right masseter and anterior temporalis muscles simultaneously), and block 3 (infusion sequence reversed). The Depression, Anxiety, and Stress Scale (DASS-21) and the Pain Catastrophizing Scale (PCS) were completed by the participants before the experiment, and the PCS was completed after the experiment. The amplitude and velocity of opening and closing movements for each task were compared between blocks (repeated-measures analysis of variance). Spearman rank correlation coefficient was used to explore correlations. Statistical significance was considered to be P .05. Results: In comparison to isotonic saline control, hypertonic saline resulted in significantly smaller opening and closing amplitudes and lower velocity during closing in free chewing, but no significant effects in the open/close task or standardized chewing. There were significant correlations between PCS scores and amplitude or velocity during isotonic saline and baseline, but not hypertonic saline. Conclusion: The pain-related reduction in amplitude and/or velocity of free chewing is consistent with the Pain Adaptation Model, but the absence of effects on the open/close task and standardized chewing is not. The few significant correlations between psychologic variables and jaw movement may reflect the low scores. Keywords: facial pain, jaw, mastication, masticatory muscles, movement, pain measurement

Aims: To test the hypotheses that, in comparison to control, the effects of simultaneous noxious stimulation of the right masseter and anterior temporalis muscles on jaw muscle activity (1) vary with the task; (2) are different between different agonist or antagonist muscles involved in a task; and (3) are correlated with mood or pain-related cognition scores. Methods: In 15 asymptomatic participants, recordings were made of jaw movement and electromyographic (EMG) activity of the right digastric and bilateral masseter and anterior temporalis muscles during standardized open/close and free and standardized chewing tasks. The tasks were repeated in three blocks: block 1 (baseline), block 2 (during simultaneous infusion of 5% hypertonic or 0.9% isotonic saline infusion into the right masseter and anterior temporalis muscles), and block 3 (infusion sequence reversed). The Depression, Anxiety and Stress Scales questionnaire was completed prior to the experiment, and the Pain Catastrophizing Scale was completed before and after the experiment. Linear mixed-effects model analysis compared root mean square (RMS) EMG activity under baseline, hypertonic saline, and isotonic saline (control), and Spearman correlations between RMS and psychologic scores were calculated. P .05 was considered significant. Results: The significant effects of pain on the activity of a jaw muscle varied with the task, were different between different agonist and antagonist muscles in a task, and were significantly correlated with some of the psychologic scores. Qualitatively, the effects noted in a particular muscle could be different between different participants. Conclusion: Simultaneous noxious masseter and anterior temporalis stimulation results in changes in jaw muscle activity that can vary with the task, the muscle, the participant, and some psychologic variables. Keywords: electromyography, jaw, mastication, masticatory muscles, pain, psychological scales

Aims: To investigate the dental and skeletal aspects of malocclusion in the anteroposterior and vertical dimensions in a sample of temporomandibular disorders (TMD) patients and to correlate these aspects with the signs and symptoms of TMD. Methods: A total of 150 TMD patients were divided into five groups according to the Diagnostic Criteria for TMD: Group 1 = myalgia (M); Group 2 = disc displacement with reduction (DDWR); Group 3 = disc displacement without reduction (DDWOR); Group 4 = degenerative disorders (D); and Group 5 = subluxation (S). Molar and canine relations, overjet, overbite, occlusal guidance, occlusal interferences, and centric slides were recorded for each patient, and the skeletal craniofacial patterns were analyzed for each patient using cone beam computed tomography. One-way analysis of variance was used to compare the variable means of the different groups. Pearson correlation coefficient was used to assess the correlations of quantitative continuous variables. Significance level was considered at P .05. Results: No significant difference was found among the groups regarding any aspects of dental occlusion except for mediotrusive interferences, which were significantly higher in Group 3 (DDWOR) (P = .02). Regarding skeletal craniofacial pattern, Group 4 (D) had significantly smaller mean ± standard deviation sella-nasion-B (SNB) point angle (74.31 ± 3.04 degrees) than Group 3 (DDWOR) (78.04 ± 4.88 degrees), and Group 1 (M) showed the greatest SNB angle (79.87 ± 3.73 degrees) (P = .03). Group 3 (DDWOR) showed significantly greater mean mandibular plane/SN angle (39.56 ± 6.19 degrees) than Group 1 (M) (34.73 ± 5.65 degrees) (P = .04). Relations between occlusal variables and TMD parameters were nonsignificant. Conclusion: This study provides robust evidence to diminish the TMD-malocclusion association, especially in myogenic types of TMD. Keywords: craniofacial pattern, DC/TMD, malocclusion, temporomandibular disorders

Aims: To elucidate the effects of decreased occlusal loading (DOL), with or without reloading (RL), on the structure and bite force function of the mandibular condylar fibrocartilage in skeletally mature male mice. Methods: At 13 weeks old, 30 wild type (WT) male mice were subjected to: (1) 6 weeks normal loading (NL); (2) 6 weeks DOL; or (3) 4 weeks DOL + 2 weeks RL. Histomorphometry, cell metabolic activity, gene expression of chondrogenic markers, and bite force tests were performed. Results: DOL resulted in a significant increase in apoptosis (P .0001) and significant decreases in fibrocartilage thickness (P .05) and hypertrophic chondrocyte markers indian hedgehog and collagen type X (P .05). A corresponding decrease in bite force was also observed (P .05). RL treatment resulted in a return to values comparable to NL of chondrogenic maturation markers (P > .10), apoptosis (P > .999), and bite force (P > .90), but not in mandibular condylar fibrocartilage thickness (P > .05). Conclusions: DOL in skeletally mature mice induces mandibular condylar fibrocartilage atrophy at the hypertrophic cell layer with a corresponding decrease in bite force. Keywords: bite force, chondrogenesis, decreased occlusal loading, mandibular condylar fibrocartilage, masticatory function