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Objectives: The study was conducted to investigate the effect of Yoga-based exercise program on pain, range of motion (ROM), quality of sleep, depression and quality of life in female patients with myofacial pain of temporomandibular disorders (TMD)., Materials and Methods: 39 Female patients with myofacial pain of TMD were included in the study. Yoga based exercise program was performed to the first group and second group was control group. Visual Analog Scale (VAS), Neck Pain and Disability Scale (NPDS), neck and jaw ROM, Pittsburg Sleep Quality Index (PUQI), Beck Depression Inventory (BDI) and Short Form 36 (SF36) were evaluated. Evaluations were repeated before treatment and 6 weeks later., Results: From the measurements, a decrease in Temporomandibular Joint (TMJ) (p = 0.005) and neck pain (p = 0.031) was found to be significant in favor of Yoga Group. It was also observed that the increase in ROM in the neck right lateral flexion (p = 0.001) in favor of Yoga Group. The sleep quality did not change. In yoga group, a decrease in depression level (p = 0,023) and increase Quality of life in parameters of physical function (p = 0.023), vital capacity (p = 0.026), emotional health (p = 0.002), mental health (p = 0.080) were found as significant, statistically., Conclusions: It was concluded that yoga-based exercise program can be used as an alternative program in patients with myofacial pain of TMD. Further study on myofascial pain of TMD is recommended., Clinical Relevance: Yoga-based exercise program can be used in patients with myofascial pain due to TMD., Competing Interests: Declarations Ethics approval and consent to informed The present study was approved by the Istanbul Medipol University Non-Interventional Clinical Studies Ethics Committee with the decision no: 10840098-07. Participants were informed about the purpose and procedure of the study before participation and that they could withdraw from the study at any time without explanation. Informed consent was obtained from participants with the Voluntary Informed Consent Form. All stages of the study were conducted according to the ethical principles set by the Declaration of Helsinki. Clinical Trial approval was obtained at clinicaltrials.gov with the number of NCT04982601. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Abstract: People with special needs, like those with Down syndrome, Parkinson disease, or dementia, frequently suffer from orofacial pain conditions and dysfunction of the masticatory system. However, the accurate assessment of orofacial pain and dysfunction in such individuals is challenging. In this review, the complexities of assessing and managing orofacial pain and dysfunction in special needs populations will be described, along with their comorbid orofacial conditions like impaired oral health, salivary problems, and movement disorders of the masticatory system. In addition, the importance of maintaining or restoring a good quality of life will be highlighted, while the urgent need for oral care as part of palliative care will be stressed as well. To accomplish all this, interdisciplinary collaboration between medical doctors and dentists should be promoted in research, education, prevention, and care provision. Therefore, this review focuses specifically on this important topic., (Copyright © 2024 International Association for the Study of Pain.)

Background: Few neuroimaging studies have investigated structural brain differences associated with variations in pain distribution., Objective: To explore structural differences of the brain in fibromyalgia (FM), temporomandibular disorder pain (TMD) and healthy pain-free controls (CON) using structural and diffusion MRI., Methods: A case-control exploratory study with three study groups with different pain distribution were recruited: FM (n = 16; mean age [standard deviation]: 44 [14] years), TMD (n = 17, 39 [14] years) and CON (n = 10, 37 [14] years). Participants were recruited at the University Dental Clinic in Malmö, Sweden. T1-weighted and diffusion MRIs were acquired, clinical and psychosocial measures were obtained. Main outcome measures were subcortical volume, cortical thickness, white matter microstructure and whole brain grey matter intensity., Results: Patients with FM had smaller volume in the right thalamus than patients with TMD (p = .020) and CON (p = .030). The right thalamus volume was negatively correlated to pain intensity (r = -0.37, p = .022) and pain-related disability (r = -0.45, p = .004). The FM group had lower cortical thickness in the right anterior prefrontal cortex than CON (p = .005). Cortical thickness in this area was negatively correlated to pain intensity (r [37] = - 0.48, p = .002)., Conclusions: This study suggests that thalamus grey matter alterations are associated with FM and TMD, and that anterior prefrontal cortex grey matter alterations are associated with FM but not TMD. Studies on chronic overlapping pain conditions are needed in relation to possible nociplastic pain mechanisms in the brain and central nervous system., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: The heterogeneity of persons with temporomandibular disorders (TMD) and the lack of effective treatments have called for a biopsychosocial model and the development of a more personalised treatment approach. Emphasis on phenotypes might be a beneficial approach., Objective: Identifying phenotypes among persons with TMD using potential prognostic factors, including personal characteristics and responses to clinical tests. Additionally, examining the distribution of TMD diagnoses within the identified phenotypes., Methods: A cross-sectional study including 208 persons (85% females) seeking physiotherapy for problems in the temporomandibular area. All participants were examined clinically and answered questionnaires electronically. The phenotypes were identified using latent class analysis based on seven potential prognostic factors selected within pain, function and psychological domains. Table analysis was used to explore the distribution of TMD diagnoses within the identified phenotypes., Results: Most participants fit into one of three identified phenotypes. Phenotype 1 (32%) was characterised by functional disability, low psychosocial scores and low risk for developing chronicity and future work disability; Phenotype 2 (29%) by parafunctional habits, low psychosocial score and seeking treatment to reduce pain; and Phenotype 3 (39%) by high levels of mental distress, fear avoidance and a large risk of future work disability. Intra-articular disorders dominated Phenotype 1, myalgia and TMD-related headache Phenotype 2, while Phenotype 3 included all the different TMD diagnoses., Conclusion: The knowledge about the three identified phenotypes might be useful for clinicians treating persons with TMD and for the development of preventive strategies and more personalised treatment., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Objective: To assess effects of stabilization splints on signs and symptoms of temporomandibular disorders of muscular origin compared to other treatments., Methods: A search for articles via six electronic databases and gray literature was conducted. The risk of bias was evaluated with the Cochrane Collaboration tool. The Grading of Recommendations Assessment, Development and Evaluation approach determined the certainty of evidence., Results: Ten articles were included. Stabilization splints (n = 160 subjects) were reported to be as effective as other treatments (n = 209 patients) on analyzed outcomes (pressure pain threshold, pain during chewing, mouth opening, spontaneous pain intensity and by palpation). Five studies were judged at low and five at some concerns of risk of bias. The certainty of evidence was very low for all outcomes., Conclusion: Positive effect on signs and symptoms of temporomandibular disorders of muscular origin, when managed with stabilization splint, could not be confirmed or refuted.

The trigeminal sensory system consists of the trigeminal nerve, the trigeminal ganglion, and the trigeminal sensory nuclei (the mesencephalic nucleus, the principal nucleus, the spinal trigeminal nucleus, and several smaller nuclei). Various sensory signals carried by the trigeminal nerve from the orofacial area travel into the trigeminal sensory system, where they are processed into integrated sensory information that is relayed to higher sensory brain areas. Thus, knowledge of the trigeminal sensory system is essential for comprehending orofacial pain. This review elucidates the individual nuclei that comprise the trigeminal sensory system and their synaptic transmission. Additionally, it discusses four types of orofacial pain and their relationship to the system. Consequently, this review aims to enhance the understanding of the mechanisms underlying orofacial pain.

Introduction: Orofacial pain and tension headache are symptoms that affect a large portion of the population, compromising productivity, social ability, and functional development. The treatment for reducing painful sensation should be chosen carefully, as pharmacological treatment may bring side effects and overload the organism of patients in pain. Low-level laser therapy has been used with local and systemic [vascular] applications for pain control. However, there is still uncertainty in the literature about the ideal dosimetric parameters for photobiomodulation treatment according to patient characteristics., Methods: The objective of this project is to validate a dosimetry model based on the relationship between the effects of photobiomodulation with anthropometric and hemodynamic variables, both in local application and systemic application in patients with symptoms of orofacial pain and tension headache. For this purpose, 180 participants with orofacial pain post-covid eligible participants will be randomly assigned to Group 1-Local Photobiomodulation, Group 2-Vascular Photobiomodulation, Group 3-Placebo Local Photobiomodulation, or Group 4-Placebo Vascular Photobiomodulation [Therapy EC-DMC device, São Carlos, Brazil,- 660 nm, 100mW] using stratified block randomization. Before the application, sociodemographic information such as age, skin phototype [classified by the Fitzpatrick scale], weight, height, body mass index [BMI], oxygen saturation [SaO2], blood pressure [BP], heart rate [HR], and thickness of skin, fat, and facial muscles will be collected. During the application, we will collect local temperature, SaO2, BP, and HR. Before and after laser application, blood levels of lactate and hemoglobin, BP, and HR will be measured in the first and last session. In addition to demographic, anthropometric, and hemodynamic variables, the penetrated energy will be quantified using a power meter, and information from orofacial pain and headache symptom questionnaires will be analyzed. The Monte Carlo simulation technique will be used to systematically study the relationship between the light penetration profile into the target tissues and the most relevant variables, namely BMI, tissue layer thicknesses, and skin phototype. Light transmittance, measured in vivo and simulated, will be compared to validate a personalized dosimetry model., Discussion: The results of this study contribute to validating a Monte Carlo Simulation model to calculate the appropriate dosimetry for photobiomodulation therapies in the control of patients with Post-Covid-19 orofacial pain., Trial Registration: Trial registration number: NCT06065969., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Schuler et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: This article explores the multiple etiologies, diagnosis, and management of orofacial pain., Latest Developments: Published in 2019, the International Classification of Orofacial Pain has become the internationally accepted classification system for primary and secondary facial pain. New discoveries in temporomandibular disorders have demonstrated that they are far more complex than the traditional dental mechanistic point of view. A 2020 consensus report released by the National Academies of Sciences, Engineering, and Medicine entitled "Temporomandibular Disorders: Priorities for Research and Care" highlighted this paradigm shift and its importance for patient care, education, and research., Essential Points: Orofacial pain comprises many disorders with different etiologies and pathophysiologies. The subjectivity of the pain experience and the interrelated anatomy and physiology of the craniofacial area add to the complexity of diagnosis when the source and etiology of pain are not clear. As orofacial pain straddles the expertise of multiple disciplines, a multidisciplinary approach combining medication, physical therapy, and procedural and psychological strategies is essential in treating patients with orofacial pain., (Copyright © 2024 American Academy of Neurology.)

Pain is a complex experience that involves sensory, emotional, and motivational components. It has been suggested that pain arising from the head and orofacial regions evokes stronger emotional responses than pain from the body. Indeed, recent work in rodents reports different patterns of activation in ascending pain pathways during noxious stimulation of the skin of the face when compared to noxious stimulation of the body. Such differences may dictate different activation patterns in higher brain regions, specifically in those areas processing the affective component of pain. We aimed to use ultra-high field functional magnetic resonance imaging (fMRI at 7-Tesla) to determine whether noxious thermal stimuli applied to the surface of the face and body evoke differential activation patterns within the ascending pain pathway in awake humans (n=16). Compared to the body, noxious heat stimulation to the face evoked more widespread signal changes in prefrontal cortical regions and numerous brainstem and subcortical limbic areas. Moreover, facial pain evoked significantly different signal changes in the lateral parabrachial nucleus, substantia nigra, paraventricular hypothalamus, and paraventricular thalamus, to those evoked by body pain. These results are consistent with recent preclinical findings of differential activation in the brainstem and subcortical limbic nuclei and associated cortices during cutaneous pain of the face when compared with the body. The findings suggest one potential mechanism by which facial pain could evoke a greater emotional impact than that evoked by body pain., Competing Interests: Declaration of competing interest The authors declare there are no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Painful temporomandibular disorder (TMD) is the common cause of chronic oro-facial pain, which may interfere with sleep. Previous studies have documented an association between sleep and TMD., Objectives: This study aimed to further explore the association of night-time sleep and daytime napping with painful TMD., Methods: A total of 419 patients (aged 31.88 ± 11.54 years with women forming 85.4%) from a TMD/Orofacial Pain center were enrolled. Patients' sleep conditions were evaluated with the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and information on night-time sleep duration, napping duration and napping frequency was interviewed. TMD was diagnosed according to the Diagnostic Criteria for TMD protocol and stratified into myalgia (muscle pain), arthralgia (joint pain) and combined (muscle and joint pain) subgroups. The severity of TMD was measured with the Fonseca Anamnestic Index (FAI) questionnaire. Restricted cubic spline (RCS) regression models were established to explore relationships between sleep and painful TMD subgroups., Results: Patients with poor sleep quality (PSQI≥6) had higher FAI scores (median 60, p < .001) and higher proportions of painful TMDs. The myalgia subgroup had higher PSQI scores (median 8, p < .001) than the arthralgia subgroup. The RCS models indicated a non-linear relationship between night-time sleep duration and myalgia (p < .001), which was not observed in arthralgia. However, there were no significant findings concerning napping and painful TMD subgroups., Conclusion: This study found that the association between sleep and TMD is mainly related to painful TMD conditions, which are associated with night-time sleep duration., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Objectives: Verify whether hypervigilance to pain (HP) and sleep quality (SQ) are confounding variables in the infrared thermography (IT) examination of the temporomandibular joint and temporal and masseter muscles., Methods: A cross-sectional and analytical study was conducted, collecting HP and SQ data from 80 participants without temporomandibular disorders (TMD), performing their IT and another 40 participants with TMD. For the selection of participants with and without TMD, the TMD Pain Screener questionnaire and axis I of the Diagnostic Criteria for Temporomandibular Disorders were applied. SQ was verified using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. For the HP assessment the Pain Vigilance and Awareness Questionnaire (PVAQ) was applied. And the IT was performed through a FLIR infrared sensor camera, model T650 Infrared., Results: No significant correlations were found between SQ and the temperatures of the areas of interest (P > .05), and regarding HP, a statistically significant positive correlation was found with the dimensionless (ρ = 0.289) and non-dimensionless (ρ = 0.223) asymmetries of temporal muscle temperatures. In the temperature comparisons between the participants without TMD and the participants with TMD, significant differences were found (P < .05), also when the group without TMD was controlled according to both HP and SQ (P < .05), with higher temperatures found in the TMD group., Conclusions: HP and SQ can be considered confounding variables in IT examination of the temporomandibular region., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology and the International Association of Dentomaxillofacial Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: This study assessed the impact of migraine and fibromyalgia (FM) in TMD patients, focusing on pain, anxiety, depression, and quality of life (QoL). Additionally, we investigated how these variables relate to the total number of comorbidities to gain insights into their interactions., Methods: A retrospective data collection was conducted during January 2016 to December 2022, involving 409 adult TMD patients. TMD patients were categorised into four groups: those without comorbidity (TMD-only) and those with comorbid migraine and/or fibromyalgia (TMD + MG, TMD + FM and TMD + MG + FM). Quantitative variables were compared among them. Linear regression was used to analyse the associations between these variables., Results: Most of study population were women (79%) with a mean age of 44.43 years. TMD + MG patients reported longer pain duration, higher pain scores and greater pain interference compared with TMD-only patients. Similarly, TMD + FM patients had higher pain intensity than patients with TMD only. Both the TMD + MG and TMD + FM groups had higher levels of anxiety, depression, and health impairment compared with patients with TMD only. Patients with all three pain conditions (TMD + MG + FM) experienced the longest pain duration, highest pain intensity, psychological distress, and impaired QoL. The result showed positive associations between pain outcomes, psychological measures, pain's impact on QoL, and the number of comorbidities and a negative association between overall health states and the number of comorbidities., Conclusions: These findings underscore the importance of considering the presence of comorbidities and addressing physical and psychological aspects in the management of TMD patients., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: Temporomandibular Disorders (TMD) is the dysfunction of group of muscles and bones in the joint area, the main symptoms of TMD are the pain of the chewing muscles and (or) the temporomandibular joints, mandibular movement disorders and joint noise. This study was designed to explore the therapeutic effects following Individual Musculoskeletally Stable (IMS) position stabilization splint therapy for TMD patients using Fricton index, cone beam computed tomography (CBCT) and surface-Electromyogram (sEMG)., Methods: In this study, we enrolled 31 TMD patients (ranging from 18 to 26 years old, including 7 males and 24 females), first Fricton index was used to evaluate the clinical curative effect of TMD with the treatment of IMS stabilization splint; then CBCT was used to observe the TMJ condylar position changes of TMD before and after the treatment of IMS stabilization splint; finally sEMG was used to observe the changes of electromyography of anterior temporalis (AT) and masseter muscles (MM) of TMD before and after the treatment of IMS stabilization splint., Results: The course of treatment was 6-8 months, with an average of 7.6 months. After the IMS stabilization splint treatment, TMD symptoms relieved, especially in pain, mandibular movement disorder, but still slightly inferior in the treatment of joint noise. And there was a statistically significant difference in the anterior and inner joint space, the condyle had the tendency of moving forward and outward. AT presented reduction significantly of EMG value at rest position after treatment., Conclusions: IMS stabilization splint is a therapeutic reversible treatment for TMD, especially for pain and mandibular movement disorder; it produces effects of forward and outward condylar movement and elimination of the masticatory muscles antagonism., (© 2024. The Author(s).)

Background: The temporal tendon is a structure often compromised in patients suffering from temporomandibular disorders (TMD), yet its intraoral location makes a standardised assessment difficult., Objectives: To evaluate the variability and accuracy to target force of a newly designed intraoral extension for a palpometer device (Palpeter, Sunstar Suisse) when compared to manual palpation, in addition to clinically assessing the mechanical sensitivity and referred sensations of the temporal tendon in healthy individuals., Methods: Experiment 1: 12 individuals were asked to target on a scale 0.5, 1 and 2 kg, for 2 and 5 s by using five different methods (Palpeter, Palpeter with three different extension shapes and manual palpation). Experiment 2: 10 healthy participants were recruited for a randomised double-blinded assessment by applying pressure of 0.5, 1 and 2 kg to the right temporal tendon with the three extensions and manual palpation. Participants rated the intensity of their sensation/pain on a 0-50-100 numeric rating scale (NRS), unpleasantness on a 0-100 NRS, and if present, they rated and drew the location of referred sensations. Repeated measures analysis of variance (ANOVA) was used in both experiments to compare differences between palpation methods. Tukey's HSD tests were used for the post hoc comparisons, and p values below .05 were considered significant., Results: Experiment 1: The extensions showed no significant differences between them regarding reliability and accuracy for all forces and durations (p > .05). The manual method was significantly less reliable and accurate when compared to the other methods (p < .05). Experiment 2: There were no significant differences between the Palpeter extensions regarding pain intensity or unpleasantness NRS scores (p > .05), but all the extensions had significantly increased pain intensity and unpleasantness when compared to manual palpation (p < .05). Similarly, the frequency of referred sensations was similar between extensions but increased when compared to manual palpation., Conclusions: The new Palpeter extensions proved to be significantly more accurate and have lower test-retest variability than the manual method in a non-clinical setting. Clinically, they showed no significant differences in NRS scores for pain intensity nor unpleasantness, with no major differences in referred sensations, making any of the extensions suitable for clinical testing of the temporal tendon in future studies., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Objectives: Acute and chronic orofacial pain are very common and remain a vexing health problem that has a negative effect on the quality of life. Serotonin (5-HydroxyTryptamine, 5-HT) is a kind of monoamine neurotransmitter that is involved in many physiological and pathological processes. However, its role in orofacial pain remains inconclusive. Therefore, this review aims to summarize the recent advances in understanding the effect exerted by 5-HT on the modulation of orofacial pain., Subjects and Methods: An extensive search was conducted on PubMed and Web of Science for pertinent studies focusing on the effects of 5-HT on the modulation of orofacial pain., Results: In this review, we concisely review how 5-HT mediates orofacial pain, how 5-HT is regulated and how we can translate these findings into clinical applications for the prevention and/or treatment of orofacial pain., Conclusions: 5-HT plays a key role in the modulation of orofacial pain, implying that 5-HT modulators may serve as effective treatment for orofacial pain. However, further research on the precise mechanisms underlying the modulation of orofacial pain is still warranted., (© 2024 Wiley Periodicals LLC.)

Background: Recent evidence suggests neuro-immune mechanisms may link dietary patterns to chronic painful conditions (CPC). In the research field of oro-facial pain (OFP), studies focuses primarily on dietary mechanical limitations due to pain and dysfunction., Objective: This narrative review aimed to overview the role of nutrition on CPC, with emphasis on temporomandibular disorder (TMD), enlightening OFP researcher on dietary assessment possibilities and providing directions for studies in the field of OFP and nutrition., Methods: A PubMed database search was performed using the MeSH and non-MeSH descriptors: "temporomandibular joint disorder"; "orofacial pain"; "musculoskeletal pain"; "chronic pain disorders"; "nutrition"; "diet"; "dietary therapy"; "dietary intake" and "inflammation". No time restrictions were applied. Literature reviews, systematic reviews, meta-analyses and clinical and pre-clinical trials were included., Results: Exogenous oxidants from unhealthy dietary patterns may contribute to peripheral and central pro-inflammatory immune signalling leading to peripheral and central sensitization. Furthermore, diets rich in bioactive compounds are suggested to contribute to pain management of CPC. High dietary intake of ultra-processed foods impacts the quality of the diet and shows adverse health outcomes. In this context, the role of nutrition on TMD remains overlooked., Conclusion: Considering diet may influence CPC, allied with the scarcity of studies evaluating the role of nutrition on TMD, well-designed clinical trials based on dietary assessments and measurements capable of evaluating food quality, UPF consumption and nutrient adequacy-added to serum nutrient levels evaluation-are suggested., (© 2024 John Wiley & Sons Ltd.)

Background: Disorders of the trigeminal nerve, a sensory nerve of the orofacial region, often lead to complications in dental practice, including neuropathic pain, allodynia, and ectopic pain. Management of these complications requires an understanding of the cytoarchitecture of the trigeminal ganglion, where the cell bodies of the trigeminal nerve are located, and the mechanisms of cell-cell interactions., Highlights: In the trigeminal ganglion, ganglion, satellite, Schwann, and immune cells coexist and interact. Cell-cell interactions are complex and occur through direct contact via gap junctions or through mediators such as adenosine triphosphate, nitric oxide, peptides, and cytokines. Interactions between the nervous and immune systems within the trigeminal ganglion may have neuroprotective effects during nerve injury or may exacerbate inflammation and produce chronic pain. Under pathological conditions of the trigeminal nerve, cell-cell interactions can cause allodynia and ectopic pain. Although cell-cell interactions that occur via mediators can act at some distance, they are more effective when the cells are close together. Therefore, information on the three-dimensional topography of trigeminal ganglion cells is essential for understanding the pathophysiology of ectopic pain., Conclusions: A three-dimensional map of the somatotopic localization of trigeminal ganglion neurons revealed that ganglion cells innervating distant orofacial regions are often apposed to each other, interacting with and potentially contributing to ectopic pain. Elucidation of the complex network of mediators and their receptors responsible for intercellular communication within the trigeminal ganglion is essential for understanding ectopic pain., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.)

Introduction: Patients with chronic headaches and chronic oro-facial pain commonly present psychosocial issues that can affect social interactions. A possible reason could be that patients with these disorders might present impairments in facial recognition, laterality judgement and also alexithymia. However, a systematic review summarizing the effects of facial emotion recognition, laterality judgement and alexithymia in individuals with headaches and oro-facial pain is still not available., Aim: The main objective of this systematic review (SR) and meta-analysis (MA) was to compile and synthesize the evidence on the occurrence of alexithymia, deficits in laterality or left-right (LR) recognition and/or facial emotion recognition (FER) in patients with chronic headache and facial pain., Methods: Electronic searches were conducted in five databases (up to September 2023) and a manual search to identify relevant studies. The outcomes of interest were alexithymia scores, speed and accuracy in LR and/or FER, or any other quantitative data assessing body image distortions. The screening process, data extraction, risk of bias and data analysis were performed by two independent assessors following standards for systematic reviews., Results: From 1395 manuscripts found, only 34 studies met the criteria. The overall quality/certainty of the evidence was very low. Although the results should be interpreted carefully, individuals with chronic headaches showed significantly higher levels of alexithymia when compared to healthy individuals. No conclusive results were found for the other variables of interest., Conclusion: Although the overall evidence from this review is very low, people with chronic primary headaches and oro-facial pain could be regularly screened for alexithymia to guarantee appropriate management., (© 2024 John Wiley & Sons Ltd.)

Background: Following peripheral nerve damage, various non-neuronal cells are activated, triggering accumulation in the peripheral and central nervous systems, and communicate with neurons. Evidence suggest that neuronal and non-neuronal cell communication is a critical mechanism of neuropathic pain; however, its detailed mechanisms in contributing to neuropathic orofacial pain development remain unclear., Highlight: Neuronal and non-neuronal cell communication in the trigeminal ganglion (TG) is believed to cause neuronal hyperactivation following trigeminal nerve damage, resulting in neuropathic orofacial pain. Trigeminal nerve damage activates and accumulates non-neuronal cells, such as satellite cells and macrophages in the TG and microglia, astrocytes, and oligodendrocytes in the trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord (C1-C2). These non-neuronal cells release various molecules, contributing to the hyperactivation of TG, Vc, and C1-C2 nociceptive neurons. These hyperactive nociceptive neurons release molecules that enhance non-neuronal cell activation. This neuron and non-neuronal cell crosstalk causes hyperactivation of nociceptive neurons in the TG, Vc, and C1-C2. Here, we addressed previous and recent data on the contribution of neuronal and non-neuronal cell communication and its involvement in neuropathic orofacial pain development., Conclusion: Previous and recent data suggest that neuronal and non-neuronal cell communication in the TG, Vc, and C1-C2 is a key mechanism that causes neuropathic orofacial pain associated with trigeminal nerve damage., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest in regard to this study., (Copyright © 2024. Published by Elsevier B.V.)

Background: There is limited knowledge about the impact of painful temporomandibular disorders (TMDs) and pain characteristics on jaw functional limitation and oral health-related quality of life (OHRQoL) in TMD patients., Objectives: The influence of painful TMDs and pain characteristics on jaw functional limitation and OHRQoL was investigated. Inter-relationships between limitation in jaw function and various OHRQoL domains, along with facial pain attributes predicting impaired jaw function and diminished OHRQoL were also examined., Methods: TMD patients were recruited from a university-based hospital. A comprehensive questionnaire comprising demographic variables, the DC/TMD Symptom Questionnaire, Graded Chronic Pain Scale, Jaw Functional Limitation Scale-8 (JFLS-8) and Oral Health Impact Profile-TMD (OHIP-TMD) was administered. Participants underwent a protocolized physical examination, and TMD diagnoses were determined utilising the DC/TMD algorithms. Participants were subsequently stratified into intra-articular/pain-related/combined TMD groups, as well as no TMD pain, acute/chronic pain and low/high-intensity pain groups. Data were assessed using non-parametric and hierarchical linear regression analyses (α = .05)., Results: The final sample consisted of 280 participants (mean age 31.2 (SD 11.8) years; 79.3% women). Significant differences in pain characteristics, JFLS-8, and global OHIP scores were observed across the various TMD subtypes, pain chronicity and pain intensity categories. Pain intensity and pain-related interference exhibited moderate correlations with JFLS-8 and global OHIP scores (rs = 0.53-0.60). Moderate associations were also noted between JFLS-8 and global OHIP, as well as most OHIP domains (rs = 0.42-0.64). Both jaw functional limitation and OHRQoL were predicted by sex, pain intensity and pain-related interference., Conclusions: Sex, pain intensity and pain-related interference are key determinants for both impaired jaw function and diminished OHRQoL, with pain-related interference exerting a more pronounced effect., (© 2024 John Wiley & Sons Ltd.)

Background: Although awake bruxism is associated with temporomandibular disorder (TMD) as well as head and neck pain, the effects of physical therapy and bruxism education to address these factors have not been investigated., Objective: The aim of this study was to evaluate the effects of oro-facial manual therapy and bruxism neuroscience education (BNE) on awake bruxism over a 3-week period with an open-ended follow-up questionnaire after 3 months., Methods: Subjects (n = 28) were randomly allocated to one of two groups, an intervention group and a control group. Data regarding disability, function and pain were collected pre- and post-assessment, with all measures administered in a single-blind fashion. Participants in both groups received six treatment sessions during this period. In addition to manual therapy, participants were provided with information on the neurophysiological mechanisms of bruxism and contributing factors. Individual behavioural guidelines and daily exercises were determined in consultation with the therapist. An introduction to a bruxism specific app (Brux.App) was also provided, which all participants used as an adjunct to their treatment., Results: The intervention group demonstrated notable improvement as indicated by their scores in the Neck Disability Index (NDI) (p = .008), Pain Disability Index (PDI) (p = .007) and Jaw Disability List (JDL) (p = .03). Furthermore, clinical assessments of the temporomandibular joint (TMJ) revealed a significant progress in terms of mouth opening (p = .03) and lateral jaw movement (laterotrusion) (p = .03). The mechanical pain threshold (PTT) of both the masseter (p = .02) and temporalis muscle (p = .05) also showed significant improvement. At 3-month follow-up, the questionnaire revealed that the majority of the intervention group (13/15, 87%) reported a benefit from the treatment., Conclusion: The reduction in pain and disability together with improvement in function and increased coping suggest a potential modification of awake bruxism through specialised musculoskeletal intervention and BNE tailored to the individual patient., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Purpose: To compile and synthesise the evidence regarding the effectiveness of aerobic exercise (AE) compared with other treatments to reduce pain and disability of individuals with orofacial pain (OFP)., Methods: Electronic searches were conducted on five databases (MEDLINE, Embase, CINAHL, Cochrane Library, and Scopus). Randomised controlled trials (RCT) or controlled trials including adults of both sexes with painful OFP diagnoses were targeted. The intervention of interest was AE (e.g., walking, cycling, running, among others), compared to any other conservative and non-conservative therapy. The primary outcome was pain intensity. The risk of bias (RoB) was determined using a compiled set of items and the Cochrane RoB-2 tools. The overall certainty of the evidence was evaluated with the GRADE approach., Results: Out of 4.669 records screened, four manuscripts were included. However, three of them used the same population but presented different outcomes. These studies included subjects with headache associated with temporomandibular disorders (TMD) and general TMD. Both studies used aerobic exercise (AE) as the intervention of interest. Manual therapy (MT) plus exercise (Ex) (strengthening exercise (Str ex) or general exercises) were used as a comparison group. The combined treatment, including a multimodal therapy (AE + MT + Str ex), was superior to MT + Ex (MD: -8.65 points [95% CI -13.73, -3.57]) on pain intensity (orofacial pain [OFP] and headache intensity) at the end of the treatment and also after 12-week follow-up (MD: -9.43 points [95% CI -14.97, -3.89]). Also, the combination of three treatment modalities (AE + MT + Ex) was better on quality of life than AE alone (MD: -14.60 points [95% CI -16.74, -12.46]) and MT + Ex (MD: -12.30 point [95% CI -14.50, -10.10]) at the end of the treatment., Conclusions: Aerobic exercise plus MT and general exercises achieved the greatest positive effects on pain and other outcomes in the short/medium term in patients with OFP. However, the scientific evidence supporting the isolated effects of AE for OFP is limited, indicating the need for more studies. Further studies are also needed to elaborate guidelines when using AE for individuals with OFP., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: Physical therapy is the preferred conservative treatment for patients with temporomandibular disorder (TMD). However, few studies have investigated the application of physical therapy in adolescents, especially follow-up studies on the long-term prognosis of these patients. This study investigated the short-term effects and long-term prognosis of physical therapy in adolescent patients with TMD and the factors influencing long-term symptoms., Methods: Information regarding baseline data, specific treatment methods, treatment times and evaluation results was collected retrospectively for adolescent patients with TMD who received physical therapy. Patients were followed up via telephone and online questionnaires, and the influence of age, sex, disease course, mouth opening, pain intensity, oral parafunctional habits and treatment methods on long-term symptoms was analysed., Results: Pain intensity, maximum mouth opening and the joint noise score improved significantly in 270/286 patients who received individualised comprehensive physical therapy. TMD-related symptoms improved with no noticeable impact on daily life in 187/199 patients who were followed up for an extended period (average, 30.71 ± 10.86 months) and were divided into asymptomatic or symptomatic groups according to the persistence of symptoms. Logistic regression analysis revealed that uncorrected oral parafunctional habits and fewer treatments were related to long-term symptoms., Conclusion: The long-term prognosis of adolescent patients with TMD after physical therapy was satisfactory. However, 52.8% of the patients experienced persistent TMD-related symptoms for an extended period, possibly due to insufficient treatment times and parafunctional habits., Trial Registration: ClinicalTrials.gov identifier: NCT05781607., (© 2024 John Wiley & Sons Ltd.)

Background: Whether pain, jaw function and quality of life are correlated with disc positions is controversial, and similar studies evaluating disc positions by magnetic resonance imaging (MRI) are very limited., Objective: This study evaluated the pain, mandibular function and quality of life of the temporomandibular disorders (TMDs) patients with different disc positions according to MRI, and the relationship among them., Methods: Three hundred and thirty-five participants were included. Patients completed questionnaires included the Numeric Rating Scale (NRS), Jaw Functional Limitation Scale 8-item (JFLS-8), the Generalised Anxiety Disorder 7-item (GAD-7), Patient Health Questionnaire 9-item (PHQ-9) and Oral Health Impact Profile for TMD (OHIP-TMD). MRI was conducted to evaluate these diagnoses, resulting in the identification of three distinct categories: normal positioning (NP), disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR)., Results: Participants had the mean age of 28.55 ± 11.10 years (80.90% women). DDwR and DDwoR had a higher percentage of females compared with NP. Significant differences existed among patients in all questionnaires. The DDwoR group had significantly the highest pain, functional limitation and the worst quality of life. Moreover, they experienced the most difficulties in chewing tough foods, yawning, experiencing pain and psychological discomfort. Moreover, the multivariate regression showed that age, female gender, diagnosis as DDwoR, GAD-7 and PHQ-9 were significantly linked to higher functional limitation. Worse quality of life was associated with age, diagnosis as DDwoR, GAD-7 and PHQ-9., Conclusions: Among patients with different disc positions, DDwoR showed the highest pain, functional limitation and the worst quality of life. Also, NP showed a proportion of chronic pain. Physical pain, psychological discomfort and chewing tough food were regarded as the most impaired. Women who experience anxiety and depression tended to have a higher propotion of dysfunction and a lower quality of life., (© 2024 John Wiley & Sons Ltd.)

Background: Temporomandibular disorders (TMDs) are conditions that involve the temporomandibular joints, masticatory muscles, and associated tissues, causing orofacial pain. Central sensitisation (CS) is a relevant part of the TMD pathophysiology. Migraine, psychological aspects, parafunctional oral habits and widespread pain are commonly associated with both TMD and CS and could confound the association between them., Objectives: To investigate the association between painful TMD and the Central Sensitisation Inventory (CSI) score, and to assess the presence of confounders in this association., Methods: Cross-sectional study that assessed women with and without orofacial pain complaints using telehealth. The TMD Pain Screener and an online physical examination determined the presence of painful TMD. The following questionnaires were applied: CSI, Headache Screening Questionnaire, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Oral Behavior Checklist, Jaw Functional Limitation Scale and the Nordic musculoskeletal questionnaire. A single regression investigated the association between the CSI score and TMD, and a multiple regression investigated the effect of the other outcomes as possible confounders. Confounding was considered present when the association between TMD and the CSI score changed more than 10% after adding a possible confounder to the regression model., Results: Forty-two women with painful TMD and 53 without TMD were included. There was a significant association between the CSI score and the presence of painful TMD (R 2  = 0.639; p < 0.001). This association changed when the following outcomes were added to the model: presence of migraine, symptoms of depression, widespread pain and parafunctional oral habits., Conclusion: The positive association between TMD and the CSI score was confounded by migraine, symptoms of depression, widespread pain and parafunctional oral habits., (© 2024 John Wiley & Sons Ltd.)

Objectives: The relationship of somatisation with facial pain duration/intensity, pain-related interference/disability and psychological distress was investigated in East Asian temporomandibular disorder (TMD) patients. Correlations between somatisation, facial pain and psychological characteristics were also explored alongside the demographic/physical factors associated with moderate-to-severe depression and anxiety., Methods: Anonymised data were acquired from records of consecutive 'first-time' patients seeking TMD care at a tertiary oral medicine clinic. Axis I physical TMD diagnoses were established utilising the diagnostic criteria for TMDs (DC/TMD) protocol and patients with TMD pain were stratified into those with pain-related (PT) and combined (CT) conditions. Axis II measures administered encompassed the Patient Health Questionnaire-15 (PHQ-15), Graded Chronic Pain Scale (GCPS), Patient Health Questionnaire-9 (PHQ-9) and General Anxiety Disorder Scale-7 (GAD-7). Individuals with PT and CT were further categorised into those without (Pain - Som/Comb - Som) and with somatisation (Pain + Som/Comb + Som). Statistical evaluations were performed with nonparametric and logistic regression analyses (α = 0.05)., Results: The final sample comprised 473 patients (mean age 36.2 ± 14.8 years; 68.9% women), of which 52.0% had concomitant somatisation. Significant differences in pain duration (Comb + Som > Pain - Som), pain-related interference/disability (Comb + Som > Comb - Som) and depression/anxiety (Pain + Som, Comb + Som > Pain - Som, Comb - Som) were discerned. Depression/anxiety was moderately correlated with somatisation (r s  = 0.64/0.52) but not facial pain characteristics. Multivariate modelling revealed that somatisation was significantly associated with the prospects of moderate-to-severe depression (OR 1.35) and anxiety (OR 1.24)., Conclusion: Somatisation exhibited a strong association with psychological distress when contrasted with facial pain in East Asian TMD patients., (© 2024 John Wiley & Sons Ltd.)

In this systematic review, we synthesize the literature investigating the effect of experimentally induced pain in the cervical, shoulder, or orofacial regions on cervical neuromuscular and kinematic features. Databases were searched up to November 1, 2023. A total of 29 studies using hypertonic saline injection (n = 27) or glutamate injection (n = 2) as experimental pain models were included. Meta-analyses revealed reduced upper trapezius activation during shoulder flexion/abduction when pain was induced in the upper trapezius (standardized mean difference: -.90, 95% confidence interval: [-1.29; -.51]), splenius capitis (-1.03 [-1.44; -.63]), and supraspinatus (-.63 [-1.25; -.01]), but not in the subacromial space (.22 [-.16; .60]). Furthermore, experimentally induced pain caused a caudal redistribution of activation within the upper trapezius (.96 [.58; 1.34]) but did not change the mediolateral distribution (.11 [-.22; .42]). None of these adaptations persisted after pain resolution. Low-quality evidence supported the absence of an effect of experimental pain on upper trapezius muscle activation during manual dexterity and cervical flexion/extension tasks, as well as on cervical flexor and extensor muscle activation during cervical and jaw tasks. Inconsistent and limited evidence, attributed to the large heterogeneity of task and outcomes, precluded drawing meaningful conclusions about the effects of experimentally induced pain in the cervical region on cervical kinematics. Overall, cervical muscle activation tended to decrease in response to experimentally induced pain, and the decrease of muscle activation depended on the location of the painful stimulus. These adaptations are only partially representative of muscle activation patterns observed in clinical populations. PERSPECTIVE: This systematic review and meta-analysis revealed a reduced or unchanged muscle activation during experimental pain in the cervical, shoulder, or orofacial regions, depending on the task and location of nociceptive stimulation. There was inconsistent evidence on cervical kinematics. These findings enhance our understanding of neuromuscular adaptations to acute experimental pain., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

This study aimed to assess the influence of streptozotocin (STZ)-induced diabetes on the nociceptive behavior evoked by the injection of hypertonic saline (HS) into the masseter muscle of rats. Forty male rats were equally divided into four groups: a) isotonic saline control, which received 0.9% isotonic saline (IS), (Ctrl-IS); b) hypertonic saline control, which received 5% HS (Ctrl-HS); c) STZ-induced diabetic, which received IS, (STZ-IS); d) STZ-induced diabetic, which received HS (STZ-HS). Experimental diabetes was induced by a single intraperitoneal injection of STZ at dose of 60 mg/kg dissolved in 0.1 M citrate buffer, and 100 μL of HS or IS were injected into the left masseter to measure the nociceptive behavior. Later on, muscle RNA was extracted to measure the relative expression of the following cytokines: cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukins (IL)-1β, -2, -6, and -10. One-way analysis of variance (ANOVA) was applied to the data (p < 0.050). We observed a main effect of group on the nociceptive response (ANOVA: F = 11.60, p < 0.001), where the Ctrl-HS group presented the highest response (p < 0.001). However, nociceptive response was similar among the Ctrl-IS, STZ-IS, and STZ-HS group (p > 0.050). In addition, the highest relative gene expression of TNF-α and IL-6 was found in the masseter of control rats following experimental muscle pain (p < 0.050). In conclusion, the loss of somatosensory function can be observed in deep orofacial tissues of STZ-induced diabetic rats.

Background: Single nucleotide polymorphisms (SNPs) may influence pain susceptibility and impact treatment response in pain-related temporomandibular disorders (TMDp)., Objective: Explore the role of COMT (rs4646310, rs6269, rs4818, rs4680) and OPRM1 (rs1799971) genotypes in regulating treatment response., Methods: Sixty TMDp patients (55 females and 5 males), diagnosed with the Diagnostic Criteria for TMD (DC/TMD), underwent standardised treatment (information and education, home physical therapy, occlusal splint) for 6 months. Treatment outcomes included: pain intensity, pain-free mouth opening, jaw functional limitation, depression, and anxiety. Genotyping for COMT and OPRM1 SNPs was performed using DNA from buccal mucosa swabs and TaqMan assays. Statistical analysis was carried out to compare the changes in treatment outcomes and the influence of genotypes on treatment response., Results: Significantly less pain reduction was observed in minor allele carriers of rs4646310, and rs4680 compared to dominant homozygous (p < .025). Minor allele carriers of rs1799971 and rs4646310 demonstrated worsening in pain-free mouth opening while dominant homozygous exhibited improvement (p < .025). Significantly less anxiety reduction was observed in minor allele carriers of rs4646310 compared to dominant homozygous (p = .003). Of the all variables assessed in the regression model, carrying a minor allele of rs1799971 predicted a poorer treatment response considering pain-free mouth opening while carrying a minor allele of rs4646310 predicted less pain and less anxiety reduction., Conclusion: Our findings indicate that certain SNP variants of the COMT and OPRM1 genes were associated with poorer treatment response and may therefore play a significant role in the classification of TMDp patients. Also, assessment of patient genotype could potentially aid in predicting treatment response., (© 2024 John Wiley & Sons Ltd.)

Objective: This study aimed to conceptualise Temporomandibular disorder (TMD) symptom burden and severity and explored their interrelationships with somatic symptoms and psychological distress., Methods: Participants were recruited from a local polytechnic. The quintessential five TMD symptoms (5Ts) of the Diagnostic Criteria for TMDs (DC/TMD) were appraised and extended to evaluate the duration, frequency, intensity and interference of discrete TMD symptoms. Global TMD severity (GS) was computed by totaling the points for all TMD symptoms and dimensions. TMD (TS) and somatic symptom (SS) burden were assessed based on the Somatic Symptoms Scale-8, while psychological distress was measured with the Depression, Anxiety and Stress Scales-21. Statistical analyses were performed using Kruskal-Wallis/Dunn tests and Spearman's correlation (α = .05)., Result: Of the 366 eligible participants (mean age 19.1 ± 2.3 years), 51.4% were 5Ts-negative and 48.6% were 5Ts-positive. Among the 5Ts-positive individuals, 25.3%/64.0% were 'bothered a little' whereas 4.5%/10.7% were 'bothered a lot' by TMD pain/headache. Correspondingly, 32.6%/12.4%/5.1% were 'bothered a little' while 2.8%/2.8%/1.1% were 'bothered a lot' by TMJ sounds/closed/open locking. TS burden was moderate-to-strongly correlated to aggregate symptom duration, frequency, intensity, interference, GS and SS burden (r s  = .50-.88). While TS burden and GS were weakly associated with psychological distress (r s  = .18-.36), SS burden was moderately related to depression, anxiety and stress (r s  = .47-.53)., Conclusions: TS burden can serve as a proxy for global TMD severity and may be more meaningful than the mere presence of TMD symptoms in clinical and research settings., (© 2024 John Wiley & Sons Ltd.)

Background: Myogenic temporomandibular disorders (M-TMD) commonly involve occlusal splint (OS) therapy and musculoskeletal physiotherapy (MPT)., Objectives: To compare the effects of combining OS with MPT and education (EG) against OS and education (CG), in chronic M-TMD patients., Methods: In this double-blind randomised controlled trial, 62 participants were assigned to either EG or CG. The primary outcomes, pain levels at rest (VAS rest), maximum oral opening (VAS open) and during chewing (VAS chew), were measured by Visual Analogue Scale (VAS) in cm. The secondary outcome was the range of motion (ROM) for maximum oral opening. Both interventions lasted 3 months, with outcomes assessed at baseline (T0), post-treatment (T1) and 3 months post-treatment (T2)., Results: Intention-to-treat analysis revealed significant improvements favouring EG (VAS rest = -1.50 cm [CI 95% : -2.67, -0.32], p = .04; VAS open = -2.00 cm [CI 95% : -3.23, -0.75], p < .01; VAS chew = -1.71 cm [CI 95% : -2.90, -0.52], p = .01; ROM = 4.61 [CI 95% : 0.93, 8.30], p = .04). Additionally, VAS measures were influenced by follow-up times (VAS rest = -0.73 cm [CI 95% : -1.30, -0.17], p = 0.03; VAS open = -0.97 cm [CI 95% : -1.57, -0.37], p < .01; VAS chew = -1.15 cm [CI 95% : -1.73, -0.58], p < .01). At T1, EG demonstrated higher number of responders compared to CG for VAS open (χ 2 (1) = 4.39, p = .04) and VAS chew (χ 2 (1) = 11.58, p < .01)., Conclusion: Adding MPT to education and OS yields better outcomes in terms of pain reduction and ROM improvement, in chronic M-TMD., Trial Registration Number: NCT03726060., (© 2024 John Wiley & Sons Ltd.)

Background: Research on temporomandibular disorder (TMD) responsiveness is scarce and limited regarding patients' representativeness., Objective(s): This study aimed to estimate minimum clinically important difference (MCID) and substantial clinical benefit (SCB) among a large and diverse patient population regarding sex and age., Methods: In this study, 162 patients participated from five hospitals. MCID and SCB in pain, functional disability and quality of life were examined with anchor-based methods. Patients' global impression of change was used as the anchor. Area under the curve (AUC) values were determined for testing accuracy. Changes from baseline and coefficient of variation by responsiveness status were calculated to explain the results of accuracy., Results: SCB was estimated to be 2.18 for the numeric rating scale (NRS) for pain (AUC: 0.80 [95% CI: 0.72-0.88]) in all patients and 2.50 in women (AUC: 0.81 [95% CI: 0.71-0.89]). The estimated SCB of NRS for discomfort (1.50) and Jaw Functional Limitation Scale for mastication (1.35) had wide CIs for AUCs. Likewise, the estimated MCIDs of NRS for pain (0.80) and NRS for discomfort (1.50) had wide CIs for AUCs. Among non-responders who did not achieve the MCID of NRS for pain, the coefficient of variation was very high for all outcomes other than the NRS for pain., Conclusion: This study investigated the responsiveness of patients with TMD using a large and diverse patient sample. SCB in pain decrease can be used to assess the responsiveness of patients with TMD. Composite outcomes should be developed to estimate MCID., (© 2024 John Wiley & Sons Ltd.)

Rhythmic masticatory muscle activity (RMMA) is a periodic muscle activity that characterises sleep bruxism (SB) events. These can occur as a single event, in pairs, or in clusters. Since RMMA episodes often occur in clusters and the relevance of this occurrence is unknown, we conducted a study to investigate the effect of RMMA clusters on sleep fragmentation and the severity of orofacial muscle pain. This study involved a secondary analysis using data from 184 adult subjects with orofacial muscle pain who underwent definitive polysomnography (PSG) for sleep bruxism diagnosis. Self-reported orofacial muscle pain (OFMP) was assessed using the numeric rating scale, and additional evaluation of side-to-side equivalence (symmetry) was described using a binary system. Among the 184 participants, 60.8% (n = 112) did not exhibit clusters and among the 72 participants with clusters, 36.1% (n = 26) and 63.9% (n = 46) were in the high and low RMMA frequency groups, respectively. The high SB group had significantly three times more phasic RMMA events than the noncluster group. A total of 89.67% (n = 165) of subjects reported orofacial muscle pain. While there was no difference in the severity of OFMP among groups, a significant decrease in symmetry between the severity of temporal muscle pain on the left and right sides was noted in the cluster group compared with the noncluster group. Clustering of RMMA events is associated with sleep fragmentation. The asymmetry of temporal muscle pain is related to the presence of RMMA clusters in sleep bruxism., (© 2023 European Sleep Research Society.)

Background: Psychosocial function of Chinese temporomandibular disorders (TMD) pain patients and the correlation with somatosensory function has not been sufficiently studied., Objective: The study aims at assessing the psychosocial function of Chinese TMD pain patients by visualisation method and evaluating the correlations with somatosensory function quantitatively., Methods: The Symptom Checklist 90 (SCL-90) questionnaire and standardised quantitative sensory testing (QST) were administered to 70 Chinese TMD pain patients and age- and gender-matched healthy controls (HCs). Of these, 40 TMD arthralgia patients received QST before and after medication. Psychosocial and somatosensory parameters were transformed into standardised scores. Differences within groups were assessed through t tests. Correlations between psychosocial and somatosensory profiles were explored through correlation analyses with Bonferroni correction for multiple comparisons., Results: 100% of the Chinese TMD pain patients exhibited psychosocial distress in contrast to HCs. Anger and hostility showed negative correlation with the thermal nonnociceptive parameter (thermal sensory limen, p =.002) and nociceptive parameters (cold pain threshold and pain pressure threshold, p<.001). Correlation analysis indicated that cold detection threshold was negatively correlated with somatization and mechanical pain sensitivity had a negative correlation with anger and hostility through medical treatment (p <.001)., Conclusions: Visual psychosocial profiles provided an easy overview of psychosocial function in Chinese TMD pain patients. Anger and hostility was associated with increased thermal nonnociceptive and nociceptive sensitivity to stimuli. Psychosocial distress might be negatively associated with TMD treatment response which indicated a possible need for psychological intervention during treatment., (© 2024 John Wiley & Sons Ltd.)

Objectives: Studies exploring variations in peripheral muscle oxygenation and pressure pain thresholds (PPT) of masticatory muscles in individuals with Temporomandibular Disorders (TMDs) are limited. The purpose of this study was to compare variations in peripheral oxygenation of the masseter muscle; PPT of the masseter and temporal muscles and correlate peripheral muscle oxygenation and PPT of the masseter muscle in individuals with different types of TMDs., Materials and Methods: Cross-sectional study involving 116 participants classified into three groups: muscle group (MG, n = 32), joint group (JG, n = 30) and muscle-joint group (MJG, n = 54). Individuals aged 26.97 ± 6.93, 68.97% female, 31,03% males were included. All participants were evaluated using the Diagnostic Criteria for Temporomandibular Disorders, Near-infrared spectroscopy (NIRS) for peripheral muscle oxygenation and pressure algometer for PPT., Results: There was no difference in masseter muscle oxygenation among groups. In the masseter muscle, a weakly positive correlation was observed between PPT and variation in tissue saturation index in the MG (rho = 0.365) and JG (rho = 0.317). In addition, the MJG expressed lower PPT (p = 0.004) than JG, demonstrating that MJG had more pain in this muscle., Conclusions: MJG have lower PPT in the masseter muscle. Although the PPT is dependent on the type of TMDs, the correlation between PPT and oxygenation is weak. All TMDs groups evaluated (MG, JG, MJG) showed hemodynamic similarities of the masseter muscle., Clinical Relevance: Understanding pain thresholds and the hemodynamic behavior of the masticatory muscles contributes to a more assertive physiotherapeutic assessment in TMDs, serving as a basis for careful and individualized interventions., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Risk factors for temporomandibular disorder (TMD) pain remain unclear., Objectives: This study aimed to identify risk factors for TMD pain using a biopsychosocial model and to investigate interactions between potential risk factors-oral behaviours (OBs), psychological factors and sleep quality-and their direct and indirect effects on TMD pain., Methods: This was a cross-sectional study of 488 patients with TMDs (422 women; 30.8 ± 9.4 years). Pain was assessed using the Numerical Rating Scale. Demographic, behavioural, psychological and biomedical data were collected through clinical examination, face-to-face interviews and questionnaires. Multiple linear regression analysis was used to identify factors associated with TMD pain. Mediation and moderation analysis were used to evaluate interactions between variables. Significant mediation ('0' not included in the 95% confidence interval (CI)) and moderation (p < .05) effects on TMD pain were identified., Results: Marital status, diagnosis subgroup, previous medication use, depression and sleep quality were significant risk factors for TMD pain (p < .05). Significant mediation effects were observed as follows: depression and sleep quality mediated the association between OBs and pain; sleep quality mediated the association between somatization, depression, anxiety and pain; and depression mediated the association between sleep quality and pain (all 95% CI did not contain '0')., Conclusions: (1) Marital status, diagnosis subgroup, previous medication use, depression and sleep quality were associated with TMD pain. (2) OBs can exacerbate pain by promoting depression and reducing sleep quality. Psychological factors and sleep quality can interact to exacerbate pain., (© 2024 John Wiley & Sons Ltd.)

Objective: This review proposes a neurobiological model for temporomandibular disorders (TMD) associated with stress and anxiety., Methods: An electronic search was performed in the PubMed, Embase, and Web of Science databases. Articles published up to 2020 were selected. The search terms were the following: temporomandibular disorders, anxiety, stress, neurobiology of stress and anxiety, and orofacial pain., Results: In total, there were 100 studies, which presented a total of 10 different analyses. The results were described, demonstrating the type of analysis that was performed on each item analyzed for a better understanding of the context., Conclusion: The conclusion is that the interactions between the masticatory system, temporomandibular joints (TMJs), and stomatognathic apparatus with "stress neuromatrix," "pain neuromatrix," "limbic system," and "neuroimmunoendocrine system" would produce the range of changes observed in neural connectivity and the diversity of symptoms presented in TMD.

Diagnosing and treating chronic orofacial pain is challenging due to its complex structure and limited understanding of its causes and mechanisms. In this study, we used RNA sequencing to identify differentially expressed genes (DEGs) in the rostral ventral medulla (RVM) and thalamus of rats with persistent orofacial pain, aiming to explore its development. DEGs were functionally analyzed using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Results showed a significant association between immune response and pain in this model. Key DEG mRNA expression trends were further validated using real-time quantitative polymerase chain reaction (RT-PCR), confirming their crucial roles in chronic orofacial pain. After injecting complete Freund's adjuvant (CFA) into the bilateral temporomandibular joint cavity for 14 days, we observed 293 upregulated genes and 14 downregulated genes in the RVM, and 1086 upregulated genes and 37 downregulated genes in the thalamus. Furthermore, we identified 27 common DEGs with altered expression (upregulation) in both the thalamus and RVM, including Cd74, C3, Cxcl13, C1qb, Itgal, Fcgr2b, C5ar1, and Tlr2, which are pain-associated genes. Protein-protein interaction (PPI) analysis using Cytoscape revealed the involvement of Toll-like receptors, complement system, differentiation clusters, and antigen presentation-related proteins in the interaction between the thalamus and RVM. The results of this study show that the immune system seems to have a more significant influence on chronic orofacial pain. There may be direct or indirect influence between the thalamus and RVM, which may participate in the regulation of chronic orofacial pain., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Chronic pain is persistent or recurrent pain lasting longer than 3 months. The experience of temporomandibular disorder (TMD)-related pain is modulated by emotional and social factors, with mindfulness encapsulating these aspects., Objective: To investigate the association between cognitive-behavioural-emotional characteristics, mindfulness and the painful experience in women with chronic pain-related TMD., Methods: A cross-sectional study was conducted, including 90 women aged between 18 and 61 years old, diagnosed with chronic pain-related TMD according to the Diagnostic Criteria for Temporomandibular Disorder, considering both temporomandibular joint and muscle pain. Specific instruments were employed to assess cognitive-behavioural-emotional aspects. The Mindful Attention Awareness Scale and the Five Facets of Mindfulness Questionnaire scales evaluated the level and construct of mindfulness. The relationship between variables was analysed using bivariate association tests (.05 > p < .20), followed by multiple regression tests (p < .05)., Results: The heightened experience of pain correlated with increasing age, a low level of education, the attribution of the locus of control by chance, and lower levels of mindfulness (p < .05). The heightened experience of pain was negatively influenced by mindfulness levels (p < .05). On the other hand, the painful experience was mainly influenced by facets describing negative formulation, distraction, non-reactivity and non-judgement (p < .05)., Conclusion: Demographic, cognitive-behavioural-emotional data and levels of mindfulness and its facets presented different influence weights on the painful experience. These findings provide support for future studies focusing on mindfulness strategies, education and pain management in women with chronic pain-related TMD., (© 2024 John Wiley & Sons Ltd.)

Background: The most common cause of mouth and facial pain is a temporomandibular joint disorder, which affects the patient's quality of life and interferes with their ability to perform daily tasks., Objective: The purpose was to compare the effects of the Post-Isometric Relaxation Technique and Bowen's Therapy on pain, range of motion and functional activity in patients with temporomandibular joint disorders., Methods: This study was a randomized clinical trial. A total of 24 participants were randomly allocated into two groups using the lottery method. Baseline treatment was the same (ultrasound and tapping) in both groups. Group 1 (12 participants) was treated with a post-isometric relaxation technique, and Group 2 (12 participants) with Bowen's therapy for two sessions per week (total duration of 4 weeks). Outcome measures were the Numeric Pain Rating Scale, Maximal mouth opening inter-incisal rural and jaw functional limitation scale-20. SPSS version 25 was used for statistical analysis., Results: A significant improvement in pain, range of motions and functional activities in the post-isometric group showed significant results (p < 0.05) as compared to Bowen's group (independent t-test). However, within-group comparison (paired t-test), both groups showed significant results (p < 0.05)., Conclusion: This study concluded that post-isometric relaxation was more effective in terms of pain, range of motions for mouth opening, lateral deviations and functional activity of temporomandibular joint disorder patients. However, both groups showed clinical results according to minimal clinical difference values., Trial Registry Number: The trial is registered under ClinicalTrials.govt with reference no. ID: NCT05392049 registered on 26/05/2022., (© 2024. The Author(s).)

Objectives: To examine the prevalence of temporomandibular disorders (TMD) in patients with juvenile fibromyalgia syndrome (JFS) and identify TMD characteristics specifically associated to JFS., Methods: Signs and symptoms of TMD were assessed using a novel clinical tool specifically devised for children that consists of: 1. a self-report multiple-choice questionnaire; 2. a protocol for the clinical examination of the orofacial region. Multivariate logistic regression model was used to identify TMD features associated with JFS., Results: Thirty JFS patients (median age 15.5 years) and 45 healthy controls (median age 15.0 years) were included in this cross-sectional study. Orofacial pain was reported by 26 of 30 JFS patients (86.7%) and by 3 of 45 controls (6.7%; p<0.001). Pain on TMJ palpation was present in 18 of 30 JFS patients (60%) and in 5 of 45 controls (11.1%; p<0.001). Median values of maximum spontaneous mouth opening, voluntary active opening and assisted passive opening were significantly higher in JFS patients than in controls. On multiple regression analysis spontaneous orofacial pain (OR: 21.0; p=0.005), diffuse tenderness on palpation of the masticatory muscles (OR: 14.9; p=0.026) and TMJ hypermobility (OR 1.42; p=0.008) were independently associated with JFS., Conclusions: The high prevalence of TMD in JFS highlights the need for a broader interdisciplinary evaluation of JFS patients. TMJ hypermobility, in addition to orofacial and masticatory muscle pain, is an important clue for the diagnosis of TMD in adolescents with JFS. Elucidating the link between these disorders will advance individualised management and improve treatment efficacy.

Background: Limitation of mouth opening, widely known as trismus, is a major symptom altering quality of life in individuals presenting from temporomandibular joint disorder or head and neck cancer. A French-language instrument addressing jaw opening limitation following treatment for head and neck cancer (HNC) or temporomandibular joint disorder (TMD) is lacking., Objective: The aim of this study was to translate and validate the Gothenburg Trismus Questionnaire-2 (GTQ-2) into French., Methods: A French translation of the GTQ-2 was performed according to established international guidelines, leading to the French-GTQ-2 (F-GTQ-2). The validation study included 154 participants with trismus (minimum interincisal opening of ≤35 mm) following treatment for TMD or HNC and 149 age-matched participants without trismus. All participants completed the F-GTQ-2 and participants with trismus completed additional health-related quality of life questionnaires to allow for analysis of convergent validity., Results: The F-GTQ-2 demonstrated retained psychometric properties with Cronbach's alpha values above 0.70 for the domains, jaw-related problems, eating limitations, facial pain and somewhat lower for muscular tension (0.60). Mainly moderate correlations were found when comparing the F-GTQ-2 to other instruments, which was in line with the pre-specified hypotheses, indicating satisfactory convergent validity. Discriminant validity was found with statistically significant differences in all domains of the F-GTQ-2 between trismus and non-trismus participants., Conclusion: The F-GTQ-2 can be considered a reliable and valid instrument to assess jaw-related difficulties in individuals with trismus due to HNC or TMD., (© 2024 John Wiley & Sons Ltd.)

Background: The trigeminal spinal subnucleus caudalis (Sp5C), also known as the medullary dorsal horn, receives orofacial somatosensory inputs, particularly nociceptive inputs, from the trigeminal nerve. In the Sp5C, excitatory and inhibitory neurons, glutamatergic and GABAergic/glycinergic neurons, respectively, form the local circuits. The axons of the glutamatergic neurons in lamina I ascend toward the thalamic and parabrachial nuclei, and this projection is the main pathway of orofacial nociception. Additionally, the axons of the higher brain regions, including the locus coeruleus, dorsal raphe, and cerebral cortex, are sent to the Sp5C., Highlight: Among these descending projections, this review focuses on the functional profiles of the corticotrigeminal projections to the Sp5C, along with their anatomical aspects. The primary and secondary somatosensory and insular cortices are of particular interest., Conclusion: Corticotrigeminal projections from the somatosensory cortex to the Sp5C play a suppressive role in nociceptive information processing, whereas recent studies have demonstrated a facilitative role of the insular cortex in nociceptive information processing at the Sp5C level., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Chronic orofacial pain (COP) therapy is challenging, as current medical treatments are extremely lacking. Moutan Cortex (MC) is a traditional Chinese medicine herb widely used for chronic inflammatory diseases. However, the mechanism behind MC in COP therapy has not been well-established. The purpose of this study was to identify the active ingredients of MC and their specific underlying mechanisms in COP treatment., Methods: In this study, the main active ingredients and compound-target network of MC in COP therapy were identified through network pharmacology and bioinformatics analysis. Adult male Sprague-Dawley rats received oral mucosa lipopolysaccharide (LPS) injection to induce COP. Pain behaviors were evaluated by orofacial mechanical nociceptive assessment after intraganglionar injection. In vitro inflammatory cytokines in LPS-pretreated human periodontal ligament stem cells (hPDLSCs) and rat primary cultural trigeminal ganglion (TG) neurons were quantified by real-time quantitative polymerase chain reaction (RT-qPCR). Schrödinger software was used to verify the molecular docking of quercetin and critical targets. Whole-cell recording electrophysiology was used to evaluate the effect of quercetin on voltage-gated sodium (Na v ) channel in rat TG neurons., Results: The assembled compound-target network consisted of 4 compounds and 46 targets. As 1 of the active components of MC correlated with most related targets, quercetin alleviated mechanical allodynia in LPS-induced rat model of COP (mechanical allodynia threshold median [interquartile range (IQR) 0.5 hours after drug administration: vehicle 1.3 [0.6-2.0] g vs quercetin 7.0 [6.0-8.5] g, P = .002). Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that immune response and membrane functions play essential roles in MC-COP therapy. Five of the related targets were identified as core targets by protein-protein interaction analysis. Quercetin exerted an analgesic effect, possibly through blocking Na v channel in TG sensory neurons (peak current density median [IQR]: LPS -850.2 [-983.6 to -660.7] mV vs LPS + quercetin -589.6 [-711.0 to -147.8] mV, P = .006) while downregulating the expression level of proinflammatory cytokines-FOS (normalized messenger RNA [mRNA] level mean ± standard error of mean [SEM]: LPS [2. 22 ± 0.33] vs LPS + quercetin [1. 33 ± 0.14], P = .034) and TNF-α (normalized mRNA level mean ± SEM: LPS [8. 93 ± 0.78] vs LPS + quercetin [3. 77 ± 0.49], P < .0001)., Conclusions: Identifying Na v as the molecular target of quercetin clarifies the analgesic mechanism of MC, and provides ideas for the development of novel selective and efficient chronic pain relievers., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Anesthesia Research Society.)

Background: Longitudinal intervention studies on treatment options in temporomandibular dysfunction (TMD) including self reports and salivary biomarkers of stress are rare and the exact therapeutic function of occlusal splints widely unknown., Methods: We examined the therapeutic effects of a Michigan splint with occlusal relevance in patients with TMD using a placebo-controlled, delayed-start design. Two intervention groups received a Michigan splint, while one of them had a placebo palatine splint for the first 3 weeks. We collected pain intensities (at rest and after five occlusal movements), salivary measures associated with stress (cortisol and alpha-amylase) and self-reported psychological distress (stress, anxiety, catastrophizing) at baseline and 3 and 7 weeks after onset of intervention., Results: At baseline, we observed increased pain intensity and psychological distress in TMD patients compared to 11 matched healthy controls. Baseline anxiety was linked to movement pain intensity through stress. Over therapy reductions in pain intensity and morning cortisol were more pronounced in those patients starting immediately with the Michigan splint, while psychological distress decreased similarly in both groups., Conclusion: Our results suggest that perceived stress plays a role for the association between anxiety and TMD pain and underlines the need for an interdisciplinary perspective on the pathogenesis and therapy of TMD in a setting where psychotherapeutic knowledge is still scarce or rarely applied., (© 2024 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: Patients with painful temporomandibular disorders (TMD) more often experience jaw functional limitations. The study of jaw functional limitations should be primarily focused on painful TMD., Objectives: The impact of TMD pain characteristics (source, chronicity and intensity) on jaw functional limitations were evaluated using Jaw Functional Limitation Scale (JFLS)., Methods: This cross-sectional study reviewed the dental records and self-report questionnaires of patients with painful TMD. The pain source, chronicity and intensity were evaluated to study the TMD pain characteristics. The jaw functional limitations were analysed using the Thai version of the JFLS., Results: A total of 176 patients with painful TMD were included in this study. The jaw functional limitations were affected only by pain intensity. Patients with TMD with severe pain intensity had significantly higher jaw functional limitations than those with mild-to-moderate pain intensity (p < .05). A significant association was observed between pain intensity and jaw functional limitations (p < .05). Mastication was highly restricted by pain intensity (odd ratio = 1.39, 95% confidence interval = 1.16-1.67)., Conclusion: The present study found a significant effect of TMD pain intensity on jaw functional limitations. Patients with severe TMD pain intensity were more likely to experience jaw functional limitations, particularly mastication limitation. Management focusing on reduction of pain intensity may improve jaw functions in patients with TMD., (© 2024 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: Oxidative stress indicators affect chronic orofacial pain (COFP), but how to reduce these effects is uncertain., Objectives: 11 oxidative stress biomarkers were collected as exposures, while four forms of COFP were chosen as outcomes for Mendelian randomization (MR) study., Methods: The effect estimates between oxidative stress and COFP were calculated using inverse variance-weighted MR (IVW-MR). Then, functional mapping and annotation (FUMA) was utilized in order to carry out SNP-based functional enrichment analyses. In addition, the IVW-MR method was applied to combine effect estimates when using genetic variants associated with oxidative stress biomarkers as an instrument for exploring potential druggable targets., Results: The results indicated that oxidative stress biomarkers (causal OR of uric acid (UA), 0.998 for myofascial pain, 95% CI 0.996-1.000, p < .05; and OR of glutathione transferase (GST), 1.002 for dentoalveolar pain, 95% CI 1.000-1.003, p < .05) were significantly linked with the probability of COFP. Functional analysis also demonstrated that UA and myofascial pain genes were prominent in nitrogen and uracil metabolism, while GST and dentoalveolar pain genes were enriched in glutathione metabolism. Also, the study provided evidence that solute carrier family 2 member 9 (SLC2A9) and glutathione S-transferase alpha 2 (GSTA2) cause discomfort in the myofascial pain (OR = 1.003, 95% CI 1.000-1.006; p < .05) and dentoalveolar region (OR = 1.001, 95% CI 1.000-1.002; p < .05), respectively., Conclusions: In conclusion, this MR study indicates that genetically predicted myofascial pain was significantly associated with decreased UA and dentoalveolar pain was significantly associated with increased GST level. SLC2A9 inhibitor and GSTA2 inhibitor were novel chronic orofacial pain therapies and biomarkers, but clinical trials are called to examine if these oxidative biomarkers have the protective effect against orofacial pain, and further research are needed to explore the underlying mechanisms., (© 2024 John Wiley & Sons Ltd.)

Purpose: To analyze the sensation of pain and the range of mandibular movements of adult individuals with temporomandibular disorder, before and after the application of the athletic tape., Method: This is a double-blind randomized clinical trial, in which 22 adults with temporomandibular disorder participated, randomly allocated into two groups, with group A comprising 10 women and one man (mean age 28.2±8.3 years) and group B comprising nine women and two men (mean age 26.2±3.9 years). Group A was submitted to the application of the athletic tape on the masseter with 40% stretch and the group B to the application of the athletic tape on the masseter without stretching. All participants underwent the application of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Pain threshold assessment was performed using an algometer to apply pressure to measurement points. The measurement of mandibular movements was performed using a caliper. The athletic tape was glued using the I technique, with a fixed point over the insertion and a movable point over the origin of the masseter muscle. Participants remained with the athletic tape for 24 hours and were re-evaluated., Results: There was pain relief in the group A in the temporomandibular joint on the right and at the origin of the masseter on the left. The group B showed a reduction in pain in the left anterior temporal region. No differences were found in mandibular movements after intervention, as well as no difference was found in the comparison by groups., Conclusion: The use of the athletic tape over the masseter muscle, with stretching, for 24 hours produced relief from the sensation of pain, on the origin of the right masseter and in the right temporomandibular joint, and, without stretching, in the left anterior temporal muscle. There was no difference in the range of mandibular movements.