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Aims: To investigate inflammatory mediator levels in TMJ synovial fluid (SF) and blood and to investigate clinical TMJ symptoms in relation to general and TMJ symptom duration in patients with rheumatoid arthritis (RA). Methods: Examination of 80 TMJs (68 patients; median age 55 years; 85% women) included the following variables: TMJ pain at rest, maximum mouth opening, and palpation; jaw movement capacity; number of painful movements; crepitus; and degree of anterior open bite. Levels of tumor necrosis factor (TNF), TNF soluble receptor II, interleukin 1β, IL-1 receptor antagonist, IL-1 soluble receptor II, and serotonin in TMJ SF and blood; systemic disease activity; and duration of general and TMJ symptoms were assessed. General symptom duration ≤ 2 years was considered early RA. Results: TMJ symptoms predominantly developed within 5 years following general symptom onset. Logistic regression analysis showed that number of involved joints, general pain, maximum mouth opening, anterior open bite, and TNF plasma levels combined explained 46% of the distinction between early and established RA. Furthermore, TMJ pain at rest and maximum mouth opening, contralateral laterotrusion, painful movements, crepitus, and SF TNF levels combined explained 35% of the distinction. In these analyses, higher general pain and maximum mouth opening, TMJ pain on maximum mouth opening, and crepitus were associated with early RA. Conclusion: This study indicates that TMJ pain and crepitus in RA usually occur within 2 years following general symptom onset. Pain-related dysfunction and structural changes develop with time. TNF in plasma and TMJ SF are associated with this development. This makes early (clinical) recognition of pain and inflammation important, enabling early treatment to minimize later irreversible damage. Keywords: inflammatory mediators, pain, rheumatoid arthritis, synovial fluid, temporomandibular joint

Aims: To compare two pain models of myalgic TMD, delayed-onset muscle soreness (DOMS) and injections of nerve growth factor (NGF), in terms of pain-related and motor function outcomes, as well as activity-related temporal summation. Methods: Fifty age- and gender-matched healthy participants were recruited and randomized into one of three groups: to a repeated eccentric contraction task to cause DOMS (n = 20), to receive NGF injections into the masseter muscle (n = 20), or to a control group (n = 10). Mechanical sensitivity of masticatory muscles, chewing parameters, jaw function limitation, maximum bite force, and activity-related temporal summation were assessed at baseline and at days 1, 2, and 7 following the intervention. Results: Compared to baseline, both model groups showed increased mechanical sensitivity, jaw function limitation, pain on chewing, and decreased chewing efficiency, lasting longer in the NGF group than in the DOMS group (P < .05). Furthermore, also compared to baseline, the NGF group showed increased pain on maximum bite and decreased pain-free maximum opening (P < .05). No increases in activity-related temporal summation were shown for any of the model groups when compared to baseline or the control group (P > .05). Conclusion: Both models produced similar painrelated outcomes, with the NGF model having a longer effect. Furthermore, the NGF model showed a more substantial effect on motor function, which was not seen for the DOMS model. Finally, neither of the models were able to provoke activity-related temporal summation of pain. Keywords: experimental pain, mechanical sensitivity, myalgia, temporal summation, trigeminal motor physiology

Aims: To examine if the existence of an association between self-reported awake oral behaviors and orofacial pain depends on the belief of patients that these behaviors are harmful to the jaw and to investigate if an additional variable (ie, somatic symptoms, depression, and/or anxiety) indirectly affects the association between the causal attribution belief and the report of awake oral behaviors. Methods: Prior to the first clinical visit, patients referred to a specialized clinic for complaints of orofacial pain and dysfunction completed a digital questionnaire. Data of 329 patients diagnosed with myalgia according to the Diagnostic Criteria for Temporomandibular Disorders (82.4% women; mean ± SD age = 41.9 ± 14.7 years) were analyzed. Results: Causal attribution belief moderated the association between awake oral behaviors and orofacial pain intensity. In addition, the relationship between causal attribution belief and self-reported oral behaviors was partially mediated by the presence of somatic symptoms (8%), depression (9%), and anxiety (16%). Conclusion: Awake oral behaviors were positively associated with orofacial pain, but only under the condition of a strong belief of the patients in causal attribution of these behaviors to the jaw pain complaint. No such association was present in case of a low causal attribution belief. It appeared that, within this patient cohort, the relationship between causal attribution belief and self-reported oral behaviors was (in part) the result of shared psychologic risk factors. Keywords: associations, awake oral behaviours, causal attribution belief, pain-related temporomandibular disorders, psychological factors

Aim: To investigate whether an international consensus exists among TMD experts regarding indications, performance, follow-up, and effectiveness of jaw exercises. Materials and Methods: A questionnaire with 31 statements regarding jaw exercises was constructed. 14 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. (Original article published in J Oral Facial Pain Headache 2019; 33:389–398. doi: 10.11607/ofph.2359) Keywords: Delphi technique, dentistry, jaw exercises, orofacial pain, physical treatment

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 assess the validity of the resting and chewing components of the recently developed observational diagnostic tool, the Orofacial Pain Scale for Non-Verbal Individuals (OPS-NVI). Methods: This cross-sectional observational study was carried out in two UK hospitals. A total of 56 participants with dementia who were admitted to the acute hospital were observed for 3 minutes during rest and during chewing, and the OPS-NVI was used to identify orofacial pain. Afterwards, the participants were asked about the presence of orofacial pain using self-report pain scales. The sensitivity, specificity, and area under the receiver operating curve (AUROC) of the OPS-NVI were calculated for each activity. Spearman coefficient was calculated to assess the correlation between the number of positively scored behavior items of the OPS-NVI and the presence of orofacial pain according to self-report. Results: According to the OPS-NVI, orofacial pain was present in 5.4% of participants during rest and in 9.1% during chewing. According to self-report, the prevalence of orofacial pain was 5.4% during rest and 10.7% during chewing. The specificity of the OPS-NVI was 98.1% to 100%, the sensitivity was 66.7% to 83.3%, and the AUROC was 0.824 to 0.917. The predictive validity showed a strong correlation (0.633 to 0.930, P .001) between the number of positive behavior items and the self-reported presence of orofacial pain. Conclusion: The resting and chewing components of the OPS-NVI showed promising concurrent and predictive validity. Nevertheless, further validation is required and highly recommended. Keywords: dementia, facial pain, hospital, observation, OPS-NVI, toothache, validation

Aims: To identify potential predictors of types of treatment indicated for patients with temporomandibular disorders (TMD) and to develop, validate, and calibrate a prediction model for type of treatment. Methods: The derivation cohort at baseline was comprised of 356 adult patients with TMD. Patient and disease characteristics were recorded at baseline as potential predictors. Types of treatment indicated for TMD patients were the end points of the model, classified into no treatment, physical treatment only (including splint and/or physiotherapy), and combined physical and psychological treatment. Multinomial logistic regression analysis was used to develop the prediction model. The internal validation, calibration, discrimination, and external validation of the model were determined. For practical use, the prediction model was converted into score charts and line charts. The score of each included predictor was produced based on the shrunken regression coefficients. Results: Patient age, gender, anxiety, sleep bruxism, pain-related TMD, function-related TMD, stress, passive stretch of maximum mouth opening, and depression were significantly associated with the type of treatment indicated for TMD patients. The multinomial model showed reasonable calibration and good discrimination, with area under the curve values of 0.76 to 0.86. The internal validity of the model was good, with a shrinkage factor of 0.89. The external validity of the model was acceptable. Conclusion: Potential predictors in patient profiles for prediction of type of treatment indicated for TMD patients were identified. The internal validity, calibration, discrimination, and external validity of the model were acceptable. Keywords: decision-making, physical therapy modalities, prognosis, splints, temporomandibular joint disorders

Aims: To develop models for prognostic prediction of oral health-related quality of life (OHRQoL) for patients with temporomandibular joint osteoarthritis (TMJ OA) at 1- and 6-month follow-ups after arthrocentesis treatment with hyaluronic acid (HA) injections once a week for 4 weeks. Methods: From a cohort of 522 adult patients with TMJ OA treated with arthrocentesis with HA injections, 510 and 463 adult patients were included in the 1- and 6-month follow-ups, respectively. Patient characteristics and history, clinical examinations, and questionnaires were recorded as potential predictors at start of treatment, and all patients underwent an identical treatment protocol. Patients' OHRQoL values at 1 and 6 months after completing the treatment were used as outcome measures. Logistic regression methods were used to develop prediction models, and the performance and validity of these models were evaluated according to state-of-the-art methods, including receiveroperating characteristics curve for the discrimination of the models and calibration plots for the calibration of the models. Results: History of mental disease, maximal protrusion of the jaw, muscular pain with palpation, joint pain with palpation, awake bruxism, chewing-side preference, and low OHRQoL at baseline were significantly associated with OHRQoL at the 1-month follow-up, while age, pain in other joints, history of mental disease, joint pain with palpation, sleep bruxism, awake bruxism, chewing-side preference, and low OHRQoL at baseline were significantly associated with OHRQoL at the 6-month follow-up. While the performance of both models was found to be good in terms of calibration, discrimination, and internal validity, the added predictive values of the 1-month and 6-month models for ruling in the risk of low OHRQoL were 19% and 31%, respectively, while those for ruling it out were 28% and 15%, respectively. Conclusion: Several predictors were found to be significantly associated with patients' OHRQoL after treatment. Both prediction models may be reliable and valid for clinicians to predict a patient's risk of low OHRQoL at follow-up, so the models may be useful for clinicians in decisionmaking for patient management and for informing the patient. Keywords: temporomandibular disorders, osteoarthritis, hyaluronic acid, arthrocentesis, oral health-related quality of life

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

Bruxism is a common phenomenon, and emerging evidence suggests that biologic, psychologic, and exogenous factors have greater involvement than morphologic factors in its etiology. Diagnosis should adopt the grading system of possible, probable, and definite. In children, it could be a warning sign of certain psychologic disorders. The proposed mechanism for the bruxism-pain relationship at the individual level is that stress sensitivity and anxious personality traits may be responsible for bruxism activities that may lead to temporomandibular pain, which in turn is modulated by psychosocial factors. A multiple-P (plates, pep talk, psychology, pills) approach involving reversible treatments is recommended, and adult prosthodontic management should be based on a commonsense cautionary approach.