BRD4 inhibition alleviates mechanical stress-induced TMJ OA-like pathological changes and attenuates TREM1-mediated inflammatory response.

The aim of this paper was to investigate the protective effects of bromodomain containing 4 (BRD4) inhibition on the temporomandibular joint osteoarthritis (TMJ OA) induced by compressive mechanical stress and to explore the underlying mechanism. In vivo, a rat model of TMJ compressive loading device was used and BRD4 inhibitor was injected into the TMJ region. HE staining and micro-CT analysis were used for histological and radiographic assessment. Immunohistochemistry and qPCR were performed to detect inflammatory cytokines expressions. High-throughput ChIP-sequencing screening was performed to compare the BRD4 and H3K27ac binding patterns between condylar cartilage from control and mechanical force groups. In vitro, the mandibular condylar chondrocytes were treated with IL-1ß. Small Interference RNA (siRNA) infection was used to silencing BRD4 or TREM1. qPCR was performed to detect inflammatory cytokines expressions. Our study showed that BRD4 inhibition can alleviate the thinning of condylar cartilage and subchondral bone resorption, as well as decrease the inflammatory factors expression both in vivo and in vitro. ChIP-seq analysis showed that BRD4 was more enriched in the promoter region of genes related to the stress and inflammatory pathways under mechanical stress in vivo. Trem1, a pro-inflammatory gene, was screened out from the overlapped BRD4 and H3K27ac increased binding sites, and Trem1 mRNA was found to be regulated by BRD4 inhibition both in vivo and in vitro. TREM1 inhibition reduced the expression of inflammatory factors induced by IL-1ß in vitro. In summary, we concluded that BRD4 inhibition can protect TMJ OA-like pathological changes induced by mechanical stress and attenuate TREM1-mediated inflammatory response.

Condição dentária de pacientes com disfunção temporomandibular / Dental condiction of patients with temporomandibular dysfunction / Condición dental de pacientes con disfunción temporomandibular

RESUMO Objetivo Avaliar a condição dentária e a dimensão vertical em pacientes portadores de DTM, bem como a idade e origem da DTM. Metodologia Realizou-se um estudo descritivo, observacional de corte transversal, com uma amostra de trinta pacientes com DTM, diagnosticado pelo Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Esta amostra foi determinada através de estimativas de atendimento, desta forma, uma amostra de conveniência. A associação entre o gênero, idade, dimensão vertical e condição dentária com DTM foram verificadas através do teste estatístico qui-quadrado, com intervalos de confiança de 95%. Resultados Constatou-se que 26 pacientes eram do sexo feminino e 4 do sexo masculino. Quinze sujeitos apresentaram idade inferior a 36,5 anos. Quanto a origem da DTM, 19 sujeitos tinham desordem articular, e 11 muscular. Determinou-se que não houve associação estatisticamente significante entre as variáveis independentes com a DTM. Conclusão Os fatores etiológicos analisados isoladamente parecem não influenciam de forma única no desenvolvimento da DTM, mas poderão atuar em conjunto com outros fatores, já que a sua causa é multifatorial.(AU)

ABSTRACT Objective To evaluate the dental condition and the vertical dimension in patients with TMD, and the age and origin of the DTM. Methods Was performed a descriptive study, observational, cross-sectional, with a sample of thirty patients with TMD, diagnosed by Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). This sample was determined based on estimates the service thus a sample of convenience. The association between gender, age, vertical dimension and dental condition with TMD were verified using the chi-square statistical test with 95% confidence intervals. Results It found that 26 patients were female and 4 males. Fifteen subjects presented aged below 36.5 years. How much the origin of the DTM, 19 subjects had articular disorder, and 11 muscle disorder. Has been determined that there was no statistically significant association between the independent variables with the DTM. Conclusion The etiological factors analyzed in isolation do not seem to influence in a unique way in the development of TMD, but may act together with other factors, because the cause is multifactorial.(AU)

RESUMEN Objetivo Evaluar la condición dental y la dimensión vertical en pacientes portadores de DTM, así como la edad y origen de la DTM. Metodología Se realizó un estudio descriptivo, observacional de corte transversal, con una muestra de treinta pacientes con DTM, diagnosticado por el Research Diagnostic Criteria para desórdenes temporomandibulares (RDC / TMD). Esta muestra se determinó a través de estimaciones de atención, a través de una muestra de conveniencia. La asociación entre el género, la edad, la dimensión vertical y la condición dental con DTM se verificó mediante la prueba estadística chi-cuadrado, con intervalos de confianza del 95%. Resultados Se constató que 26 pacientes eran del sexo femenino y 4 del sexo masculino. 15 sujetos presentaron una edad inferior a 36,5 años. En cuanto al origen de la DTM, 19 sujetos tenían desorden articular, y 11, muscular. Se determinó que no hubo asociación estadísticamente significativa entre las variables independientes con la DTM. Conclusión Los factores etiológicos analizados aisladamente parecen no influenciar de forma única en el desarrollo de la DTM, pero podrán actuar en conjunto con otros factores, ya que su causa es multifactorial.(AU)

Valoración del control postural y del equibrio en personas con trastornos temporomandibulares: revisión sistemática / Assessment of postural control and balance in persons with temporomandibular disorders: A systematic review

El sistema estomatognático es la unidad anatomofuncional de la región craneocervicofacial. Existen disfunciones condicionantes en su control motor. El objetivo fue estudiar la utilidad clínica de las diferentes escalas e instrumentos empleados en la valoración del control postural en personas con trastornos termporomandibulares. Se realizó una revisión sistemática, por 2revisores independientes, en las bases de datos PubMed, Medline, Ebsco, Science Direct y PEDro, seleccionando estudios observacionales publicados entre enero de 2006 y marzo de 2017. Se analizó el riesgo de sesgo y la calidad metodológica siguiendo las indicaciones Cochrane y la escala de Downs and Black. Se incluyeron 10estudios, de los que 9emplearon plataformas computarizadas, uno sumó la fotogrametría y uno usó electromiografía. Siete estudios fueron clasificados como de calidad moderada y 3de calidad baja. La posturografía es el instrumento de valoración más utilizado. Diversidades metodológicas no permiten determinar sus implicaciones clínicas ni la relación entre el equilibrio y la presencia de trastornos temporomandibulares

The stomatognathic system is the anatomo-functional unit of the cranio-cervico-facial region. Some dysfunctions affect its motor control. The aim of this study was to analyse the clinical usefulness of the various scales and instruments used in the assessment of postural control in people with temporomandibular disorders. A systematic review was carried out by 2independent reviewers in the PubMed, Medline, Ebsco, Science Direct and PEDro databases, selecting observational studies published between January 2006 and March 2017. The risk of bias and methodological quality was analysed following Cochrane indications and the Downs and Black quality scale. Ten studies were included, of which 9used computerised platforms, one added photogrammetry and one used electromyography. Seven studies were classified as moderate quality and 3as low quality. Posturography was the most widely used assessment instrument. Methodological differences did not allow determination of their clinical implications or the relationship between balance and the presence of temporomandibular disorders

Platelet-Rich Plasma in Treatment of Temporomandibular Joint Dysfunctions: Narrative Review.

BACKGROUND: The aims of this narrative review were to examine up-to-date literature in order to evaluate the effectiveness of arthrocentesis or injections with platelet-rich plasma in temporomandibular affections and to compare them to arthrocentesis alone or with hyaluronic acid (HA) or to hyaluronic acid injections. METHODS: The search of international literature was made on the PMC, PubMed and Cochrane databases, including all full-length text of studies on humans focused on osteoarthritis and disc displacements and their treatment with platelet-rich plasma arthrocentesis or injections. All design studies were included in the review and they were examined for three different outcomes: pain, joint sound and mandibular motion. English papers were only selected. RESULTS: Even though the low number of studies in this field, arthrocentesis with platelet-rich plasma and platelet-rich plasma injections in temporomandibular disorders' management were found to be effective in reducing pain and joint sound as well as in improving mandibular motion in a maximum follow-up of 24 months. CONCLUSION: Comparison to arthrocentesis alone or to HA use in arthrocentesis or by injections provided encouraging results in terms of the effectiveness of platelet-rich plasma use.

A efetividade de dois tratamentos para disfunção temporomandibular muscular: estudo piloto / The effectiveness of two treatments for muscle temporomandibular dysfunction: pilot study

Objetivo: comparar a eficácia de dois protocolos de tratamento para disfunção temporomandibular (DTM) de origem muscular. Sujeitos e método: Estudantes da Faculdade Especializada na Área de Saúde do Rio Grande do Sul foram selecionados por meio de questionário, para avaliar a presença de sinais e sintomas de DTM e diagnóstico de DTM muscular pelos Critérios de Diagnóstico para Transtornos da Pesquisa Temporomandibular. Dez estudantes compuseram a amostra, divididos em dois grupos, de acordo com o protocolo de tratamento: G1 ­ hipertermia induzida, exercícios mandibulares e massagem; e G2 ­ agulhamento seco, hipertermia induzida, exercícios mandibulares e massagem. Os alunos foram instruídos a realizar o protocolo do tratamento G1 todos os dias em casa e na instituição de ensino por três sessões, que ocorreram a cada cinquenta dias. O agulhamento seco foi realizado no G2 apenas nas segunda e terceira sessões de tratamento. Para avaliar a efetividade dos dois tratamentos antes e após cada sessão, avaliaram-se: abertura bucal (AB), por meio de régua milimetrada; dor, pela escala visual analógica; força de mordida (FM), usando um medidor de força digital; e qualidade de vida, avaliada imediatamente antes do início do tratamento e depois do término do tratamento. Resultados: a dor mostrou diferença estatística significativa no G2 após a segunda sessão (p=0,020) e a terceira sessão (p=0,047). Os demais resultados mostram que não houve diferença estatisticamente significativa entre os grupos (p>0,05). Conclusão: considera-se que neste estudo piloto ambos os tratamentos foram eficazes para DTM muscular, uma vez que todos os pacientes apresentaram melhora dos sintomas. Não houve diferença estatisticamente significativa entre os tratamentos, exceto a dor pós-procedimento, causada pela técnica do agulhamento seco. (AU)

Objective: the present study aims to compare the efficacy of two treatment protocols for temporomandibular dysfunction (TMD) of muscular origin. Subjects and method: students of the Faculdade Especializada na área de Saúde do Rio Grande do Sul, that were selected through the questionnaire to evaluate the presence of TMD signs and symptoms and diagnosis of muscular TMD from the Diagnostic Criteria for Temporomandibular Research Disorders. Ten students composed the sample, divided into two groups according to the treatment protocol: hyperthermia induced by G1, mandibular exercises and massage; G2 ‒ dry needling, induced hyperthermia, mandibular and massage exercises. Students were instructed to complete the G1 treatment protocol every day at home and at the educational institution for three sessions that occurred every fifty days. Dry needling was performed in G2 only in the second and third treatment sessions. To evaluate the effectiveness of the two treatments before and after each session, we evaluated: mouth opening (AB), through a millimeter ruler; visual analogue scale; bite force (FM) using a digital force gauge and quality of life was assessed immediately prior to initiation of treatment and after termination of treatment. Results: pain obtained a statistically significant difference in G2 after the second session (p=0.020) and the third session (p=0.047). The other results show that there was no statistically significant difference between the groups (p>0.05). Conclusion: it is considered that in this pilot study both treatments were effective for muscular TMD, since all the patients presented improvement of the symptoms. There was no statistically significant difference between treatments, except for post- -procedure pain, caused by the dry needling technique. (AU)

Characteristics of Glutamate-Evoked Pain in the Masseter Region: Differences Between Targeted Injections in Subcutaneous, Muscle, and Bone Tissues.

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

Relación entre síndrome de disfunción temporomandibular y síndrome de latigazo cervical tras un accidente de tráfico. Estudio de cohortes / Relationship between temporomandibular disorders and whiplash after a traffic accident. Cohorts study

Introducción: El síndrome de latigazo cervical (SLC) es una patología frecuente, y según la bibliografía existe controversia acerca de una relación entre este y el síndrome de disfunción temporomandibular (SDT). El objetivo de este estudio es determinar si existe una mayor incidencia de SDT en pacientes diagnosticados de SLC durante los 3 y 12 primeros meses tras haber sufrido un accidente de tráfico y determinar factores de riesgo asociados. Pacientes y método: Estudio de cohortes prospectivo comprendido entre febrero del 2013 a diciembre del 2015 que consta de una cohorte expuesta de 71 adultos (36 hombres y 35 mujeres) que habían sufrido un SLC de grado I o II según la Québec Task Force, y una cohorte no expuesta de 70 adultos (46 hombres y 24 mujeres). Se avaluaron a los 3 y 12 meses mediante el Índice Anamnésico Simplificado de Fonseca (IASF) Resultados: Los resultados obtenidos muestran que en la cohorte expuesta la proporción de SDT a los 3 meses es estadísticamente superior que en la cohorte no expuesta (53 versus 13,4%; p<0,0001). A los 12 meses se evidencia que en la cohorte expuesta la proporción de SDT es estadísticamente superior que en la cohorte no expuesta (53,2 versus 21,7%; p<0,0005). Conclusiones: Las personas que sufren un SLC presentan una mayor probabilidad de desarrollar un SDT. Además, la cohorte expuesta muestra un empeoramiento en las puntuaciones del IASF. Aquellas personas que manifiestan dorsalgia y parestesias tras sufrir un SLC presentan una mayor probabilidad estadísticamente significativa de desarrollar un SDT

Introduction: Whiplash is a frequent condition in rehabilitation centres, and according to the literature there is a great controversy about its relationship with temporomandibular disorders (TD). The objective of this study is to determine whether there is a higher incidence of TD in patients diagnosed with whiplash during the first 3 and 12 months after having suffered a vehicle accident, and to determine associated risk factors. Patients and method: Prospective cohort study conducted between February 2013 to December 2015 with a cohort of 71 adults (36 men and 35 women) that had suffered a Quebec Task Force whiplash grade I or II, together with an unexposed cohort of 70 adults (46 men and 24 women). They were evaluated at 3 and 12 months using the Fonseca's Simplified Anamnestic Index (IASF) Results: The results obtained at 3 months showed that the proportion of TD in the exposed cohort was statistically higher than in the non-exposed cohort (53.0% versus 13.4%, P<.0001). At 12 months, the results showed that the proportion of SDT was statistically higher in the exposed cohort than in the non-exposed cohort (53.2% versus 21.7%, P<.0005). Conclusions: After a whiplash there is a greater probability of developing a TD. In addition, in the exposed cohort there is a greater deterioration over time in the IASF. The back pain and paraesthesias after a whiplash are symptoms to be taken into account, as they show a statistically significant probability of developing TD

Spontaneous brain activity and connectivity in female patients with temporomandibular joint synovitis pain: a pilot functional magnetic resonance imaging study.

OBJECTIVE: It has been proposed that mechanisms in the central nervous system contribute to the development and maintenance of pain in temporomandibular disorders. In this study, we tested whether spontaneous brain activity and functional connectivity (FC) were altered in patients with temporomandibular joint synovitis pain. STUDY DESIGN: A prospective, cross-sectional design was adopted. Each of 8 patients and 10 healthy controls (HCs) underwent 2 sessions of functional magnetic resonance imaging: mouth closed and mouth open (painful for patients). Regional homogeneity (ReHo) was used to measure spontaneous brain activity in each participant. Brain areas with altered ReHo in patients compared with HCs were identified, and their FCs with the rest of the brain was examined and compared. RESULTS: Compared with HCs, patients showed decreased pain-related ReHo in the right anterior insula (rAI). The rAI showed a weaker positive FC with the left middle cingulate cortex (MCC) and a weaker negative FC with the right precuneus in patients compared with HCs. Furthermore, the rAI-MCC FC showed a negative correlation with pain intensity in patients. CONCLUSIONS: These results provide evidence supporting altered pain-related spontaneous brain activity and functional connectivity in the central nervous system in patients with temporomandibular joint synovitis pain.

[Electromyographic characteristics of temporal and masticatory muscles in patients with compression-dislocation dysfunction of temporomandibular joints of different severity].

OBJECTIVE: Introduction: The main causes of dysfunctional conditions of the temporomandibular joints (TMJ), are occlusal, neurogenic, orthodontic disorders. The muscular component of TMJ is determines the dynamic anatomical and functional state of the mandible Therefore, in the diagnosis of dysfunctions and understanding of their pathogenesis belongs to the electromyographic method of investigation. The aim of the work was a comparative assessment of the bioelectrical activity of the actual chewing and temporal muscles in patients with musculo-articular compressiondislocation dysfunction of the TMJ of various severity. PATIENTS AND METHODS: Materials and methods: Electromyographic studies of temporal and masticatory muscles were performed in 43 patients. Was assess maximal parameters were recorded with the greatest compression of teeth and in the periods of chewing on the side of the pain symptom and on the opposite side (µV), the frequency of filling the myogram (Hz), the time of activity (Ta) and the resting time (Tc), coefficient "K", which determines the ratio of the processes of activity and rest with functional samples (K = Ta / Tc). RESULTS: Results and conclusions: The main feature of the functional properties of the studied muscles in the compression-dislocation dysfunction of the TMJ is the prevalence of the maximum indices of their bioelectrical activity on the side of the joint with the dislocation of the articular head of the mandible in comparison with the joint, which is in a compression state both during periods of compression of the teeth and mastication. This kind of discoordination in the work of the muscular masticatory apparatus is reflected in the severity of the course of dysfunction.

Temporomandibular dysfunction

BACKGROUND: Orofacial pain is a common presentation in the primary healthcare setting and temporomandibular dysfunction represents one of the major causes. Its aetiology is multifactorial, caused by both masticatory muscle dysfunction and derangement within the temporomandibular joint. OBJECTIVE: The aim of this article is to provide an overview of temporomandibular dysfunction, its management and referral considerations for general practioners. DISCUSSION: Temporomandibular joint dysfunction affects a large number of adults. Conservative management involving non-pharmacological and pharmacological therapies is effective in the majority of cases.

Assessment of Temporomandibular Joint Dysfunction in Patients with Stroke.

GOAL: The aim of this study was to assess temporomandibular joint dysfunction in patients with stroke. MATERIALS AND METHODS: Total of 100 participants, 50 healthy and 50 who had stroke, were recruited into this study. Digital caliper and algometer were used to assess temporomandibular joint range of motion and masticatory muscle pressure pain threshold. Labial commissure angle measurement was used for the assessment of facial paralysis severity. Fonseca questionnaire was used for temporomandibular joint dysfunction assessment and categorization. In addition, dominant mastication shift was measured by the question that asks the pre and poststroke dominant mastication side. FINDINGS: In intergroup comparison, significant decrease was found in all temporomandibular range of motion parameters in favor of stroke group (P < .05). Despite the fact that no significant difference was found between groups for the pain threshold in masticatory muscles except for middle part of the left temporalis muscle, values were higher in healthy group (P > .05). As a result of intergroup examination of labial commissure angle degree, Fonseca questionnaire score, it was found that labial commissure angle and Fonseca questionnaire scores were higher in stroke group (P < .05). Intragroup examination of patients with stroke showed that dominant mastication side shift was seen in patients with stroke (P < .05). CONCLUSION: It was concluded that, temporomandibular joint dysfunction prevalence was higher in stroke group compared with healthy group and use of modalities specific to temporomandibular joint dysfunction treatment would be beneficial.

Efficacy of stabilisation splint treatment on the oral health-related quality of life-A randomised controlled one-year follow-up trial.

The aim of this randomised controlled trial was to assess the efficacy of stabilisation splint treatment on the oral health-related quality of life OHRQoL during a 1-year follow-up. Originally, the sample consisted of 80 patients (18 men, 62 women) with temporomandibular disorders (TMD) who had been referred to the Oral and Maxillofacial Department, Oulu University Hospital, Finland, for treatment. Patients were randomly designated into splint (n = 39) and control group (n = 41). Patients in the splint group were treated with a stabilisation splint. Additionally, patients in both groups received counselling and instructions on masticatory muscle exercises. The patients filled in the Oral Health Impact Profile-14 (OHIP-14) questionnaire before treatment and at 3 months, 6 months and 1 year. At total, 67 patients (35 in the splint group vs. 32 in the control group) completed the questionnaire at baseline. The outcome variables were OHIP prevalence, OHIP severity and OHIP extent. Linear mixed-effect regression model was used to analyse factors associated with change in OHIP severity during the 1-year follow-up, taking into account treatment time, age, gender and group status. OHIP prevalence, severity and extent decreased in both groups during the follow-up. According to linear mixed-effect regression, decrease in OHIP severity did not associate significantly with group status. Compared to masticatory muscle exercises and counselling alone, stabilisation splint treatment was not more beneficial on self-perceived OHRQoL among TMD patients over a 1-year follow-up.

Multimodal physiotherapy treatment based on a biobehavioral approach for patients with chronic cervico-craniofacial pain: a prospective case series.

The purpose of this prospective case series was to observe and describe changes in patients with chronic cervico-craniofacial pain of muscular origin treated with multimodal physiotherapy based on a biobehavioral approach. Nine patients diagnosed with chronic myofascial temporomandibular disorder and neck pain were treated with 6 sessions over the course of 2 weeks including: (1) orthopedic manual physiotherapy (joint mobilizations, neurodynamic mobilization, and dynamic soft tissue mobilizations); (2) therapeutic exercises (motor control and muscular endurance exercises); and (3) patient education. The outcome measures of craniofacial (CF-PDI) and neck disability (NDI), kinesiophobia (TSK-11) and catastrophizing (PCS), and range of cervical and mandibular motion (ROM) and posture were collected at baseline, and at 2 and 14 weeks post-baseline. Compared to baseline, statistically significant (p < 0.01) and clinically meaningful improvements that surpassed the minimal detectable change were observed at 14 weeks in CF-PDI (mean change, 8.11 points; 95% confidence interval (CI): 2.55 to 13.69; d = 1.38), in NDI (mean change, 5 cm; 95% CI: 1.74-8.25; d = 0.98), and in the TSK-11 (mean change, 6.55 cm; 95% CI: 2.79-10.32; d = 1.44). Clinically meaningful improvements in self-reported disability, psychological factors, ROM, and craniocervical posture were observed following a multimodal physiotherapy treatment based on a biobehavioral approach.

[Correlation of functional state of dental system and emotional stress in young adults]. / Vzaimosviaz' funktsional'nogo sostoianiia zubocheliustnoi sistemy i psikhoémotsional'nogo napriazheniia u lits molodogo vozrasta.

The aim of the study was to evaluate correlation of dental system functional status and emotional stress level in young adults. The study involved 164 patients aged 20-25 years. TMJ dysfunction was diagnosed according to M. Ahlers and H. Jakstat criteria (2000). All patients underwent electromyography (EMG) of mastication muscles at rest and by functional test. Emotional stress and anxiety were assessed by Holmes and Rahe stress scale, Jakhin-Mendeleevich clinical questionnaire and State-Trait Anxiety Inventory. The study revealed correlation between EMG activity of masticatory muscles and emotional stress level highlighting the importance of stress assessment in TMJ dysfunction planning.

Oral Behaviors and Parafunctions: Comparison of Temporomandibular Dysfunction Patients and Controls.

The aim of this study is to evaluate the frequency of oral behaviors in patients with temporomandibular disorders (TMD) and a control group without TMD.In this baseline case-control study, 260 controls and 260 subjects with TMD completed the oral behaviors checklist defined as a "self-report scale for identifying and quantifying the frequency of jaw overuse behavior" and underwent clinical examinations using the DC/TMJ international examination form (version May 12, 2013). Relationships of oral parafunctions' frequencies between groups were examined. The statistical analysis was performed with IBM SPSS Statistics 23 software.Age and gender distribution in the study groups did not reveal statistical differences (P > 0.05). Multivariate logistic regression analysis was conducted to establish system of independent oral behaviors for prognosis TMD. The stepwise regression analysis demonstrated that very frequent expression of holding, tightening, or tense muscles is associated with 10.83 times (P < 0.05) higher risk of TMD, grinding teeth together during waking hours with 4.94 times (P < 0.05) higher risk, and sustained talking with 2.64 times (P < 0.05) higher risk of TMD. By contrast, it was determined that 3 oral behaviors were less common in the TMD patients compared with the control group: clenching teeth together during waking hours, facing grimaces, and yawning (P < 0.05). The individuals with TMD reported a significantly higher frequency of 10 behaviors (P < 0.05), 3 of which may be regarded as independent risk factors for TMD. In addition, 3 oral behaviors were more frequently observed in the healthy subjects than in the TMD patients.

Evaluation of articular disc loading in the temporomandibular joints after prosthetic and pharmacological treatment in model studies.

BACKGROUND: Temporomandibular joint dysfunction is often related to excessive load in the stomatognathic system. OBJECTIVES: The objective of the model tests, using numeric calculations, was to assess the articular disc loads in the temporomandibular joints after prosthetic and pharmacological treatment of functional disorders of the masticatory organ. MATERIAL AND METHODS: The study involved 10 patients, aged 21-48 years, of both sexes, randomly selected from a group of 120 patients treated with relaxation occlusal splints (60 patients, group I) and intramuscular injection of botulinum toxin type A (60 patients, group II), suffering from temporomandibular joint dysfunction with the dominant muscle component. In all subjects, a specialized functional examination was carried out. Treatment groups: occlusal splint therapy (group I) and intramuscular injection of botulinum toxin type A (group II). An assessment of the loads of 4 disc zones of the temporomandibular joints was carried out based on the results of clinical studies (phase I of the study), and numeric model tests (phase II). In the representatives of the study groups (5 patients in each group), measurements of occlusal forces and an evaluation of tension of the masseter and temporalis muscle were performed. RESULTS: The results of the average load values for all evaluated zones of the right and left articular disc differ in a statistically significant way in favor of group II, with the exception of the external mid part of the discs. In the case of the anterior of the right disc, the load was lower in patients belonging to group I than in those obtained in group II. CONCLUSIONS: Botulinum toxin type A significantly reduces the loads within the temporomandibular joints, generated by masseter muscle hypertonia.

Assessment of treatment response to splint therapy and evaluation of TMJ function using joint vibration analysis in patients exhibiting TMJ disc displacement with reduction: A clinical study.

Context, Aim, and Objectives: Diagnosis of temporomandibular joint (TMJ) disc displacement with reduction (DDR) is difficult. Literature combining different subjective parameters of TMJ function with an objective evaluation of TMJ function using joint vibration analysis (JVA) is limited. Hence, the study was planned to diagnose temporomandibular disorder accurately, to do a subjective and objective evaluation of TMJ function, and to assess the effectiveness of different types of splint therapy over the conventional anterior repositioning appliance (ARA) group. DESIGN: Single-blind, randomized, comparative clinical trial conducted in thirty patients, 18-55 years of age, allocated to three groups, i.e., ARA conventional group, centric stabilization splint (CSS), and Soft splint (SS) groups. SUBJECTS AND METHODS: Preoperative values of comfortable mouth opening (CMO) in mm, maximum mouth opening (MMO) in mm, TMJ clicking and tenderness (grading 0-3), visual analog scale pain score (0-10 cm), and total energy (TE) integral values of both TMJs using JVA were recorded. Postoperative values were taken at the time of delivery of splint at 1st, 2nd, 6th, and 10th week. Statistical Analysis and Results: Intergroup comparison - Kruskal-Wallis test showed no statistically significant difference in CMO, MMO, and TE values of right TMJs among three groups at any point. No significant difference was seen in TMJ clicking and tenderness among groups at any point of time except at 10 weeks and at 2 weeks, respectively, by Chi-square test. Intragroup comparison - Wilcoxon signed-rank test showed the significance of difference (P < 0.05*) in postoperative visits for CMO, MMO, pain score, and TE values. Clinical effect size, extent, consistency, and percentage of cases showing improvement were maximum for CSS group. CONCLUSIONS: The study concludes that the use of JVA for diagnosis along with history and clinical examination increases the accuracy of the diagnosis of DDR. ARA group was used as a conventional treatment option. Although statistically significant difference in pre- and post-treatment values was obtained in all the three groups, CSS group patients showed consistent clinically effective responses and more significant improvement in the subsequent follow-up visits than SS group. Hence, it is advisable to start therapy with CSS splint in TMJ DDR patients to get sooner and effective results without minimum side effects.

Temporal summation and motor function modulation during repeated jaw movements in patients with temporomandibular disorder pain and healthy controls.

Temporal summation of nociceptive inputs may be an important pathophysiological mechanism in temporomandibular disorders (TMD) pain; however, it remains unknown how natural jaw function relates to underlying pain mechanisms. This study evaluated changes in pain and movement patterns during repeated jaw movements in patients with painful temporomandibular joints (TMJ) compared with healthy controls. Twenty patients with TMD with TMJ pain, and an anterior disk displacement without reduction and 20 age- and gender-matched healthy volunteers were included. Participants performed 20 trials (4 × 5 sessions) of standardized and repeated mandibular movements, and scored the movement-associated pain intensity on 0 to 10 numeric rating scale in addition to measurements of jaw movements. Patients with TMJ pain reported higher baseline pain compared to the control group for all types of jaw movements (P = 0.001) and significant increases in numeric rating scale pain scores by repetition of jaw movements (P < 0.001), which was not observed in the control group (P > 0.05). Jaw total opening distance (P = 0.030), maximum opening velocity (P = 0.043) and average closing velocity (P = 0.044) in the TMJ pain group were significantly reduced during the repeated movements. In the control group, however, total opening distance (P = 0.499), maximum opening velocity (P = 0.064), and average closing velocity (P = 0.261) remained unchanged, whereas average opening velocity (P = 0.040) and maximum closing velocity (P = 0.039) increased. The study demonstrates that repeated jaw movements constitute a sufficient and adequate stimulation for triggering temporal summation effects associated with significant inhibition of motor function in painful TMJs. These findings have practical implications for diagnosis of TMD pain and for more mechanism-driven management protocols in the future.

Influence of sustained submaximal clenching fatigue test on electromyographic activity and maximum voluntary bite forces in healthy subjects and patients with temporomandibular disorders.

This study aimed to investigate whether the fatigue induced by sustained motor task in the jaw elevator muscles differed between healthy subjects and patients with temporomandibular disorder (TMD). Fifteen patients with TMD and thirteen age- and sex-matched healthy controls performed a fatigue test consisting of sustained clenching contractions at 30% maximal voluntary clenching intensity until test failure (the criterion for terminating the fatigue test was when the biting force decreased by 10% or more from the target force consecutively for >3 s). The pre- and post-maximal bite forces (MBFs) were measured. Surface electromyographic signals were recorded from the superficial masseter muscles and anterior temporal muscles bilaterally, and the median frequency at the beginning, middle and end of the fatigue test was calculated. The duration of the fatigue test was also quantified. Both pre- and post-MBFs were lower in patients with TMD than in controls (P < 0·01). No significant difference was found in the percentage change in MBF between groups. The duration of the fatigue test in TMD patients was significantly shorter than that of the controls (P < 0·05). Our results suggest that, compared to healthy subjects, patients with TMD become more easily fatigued, but the electromyographic activation process during the fatigue test is similar between healthy subjects and patients with TMD. However, the mechanisms involved in this process remain unclear, and further research is warranted.

Evaluation of the influence of experimental psychological stress on the quantitative sensory testing response in temporomandibular disorders patients / Avaliação da influência de estresse psicológico experimental na resposta de testes sensoriais quantitativos em pacientes com disfunção temporomandibular

Background: Quantitative sensory testing (QST) is a promising method for assessing the mechanisms that contribute to the development and maintenance of painful Temporomandibular Disorders (TMD). All QST responses rely on the participant´s perception; therefore a number of cognitive and psychological factors are known to directly influence results, including psychological stress. Aims: To assess the effects of experimental psychological stress on QST response in TMD patients and healthy volunteers. Methods: 20 women with myofascial TMD and 20 healthy women underwent a standardized QST protocol, including cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical pain threshold (MPT), pressure pain threshold (PPT) and wind up ratio (WUR) at the masseter muscle. QST was conducted before and after to the Paced Auditory Serial Addition Task (PASAT), inducing acute psychological stress. ANOVA with repeated measures was performed to assess the effect of group and time on the reported stress and absolute values of QST. The significance level was set at 5% (p=0.050). Furthermore, Z-score profiles were generated. Results: The PASAT induced a significant stress reaction (p<0.001). After exposure to experimental stress, both healthy volunteers and TMD patients showed increase in thermal detection threshold (CDT: F=4.25, p=0.017 and WDT: F=4.10, p=0.020) and decrease in thermal pain threshold (CPT: F=11.2, p<0.001 and HPT: F=8.13, p<0.001) when compared to baseline. However, stress did not induce significant changes in MPT, PPT or WUR in both groups (p>0.050). Conclusion: The experimental psychological stress induces thermal hypoesthesia and thermal hyperalgesia on masticatory muscle, regardless of the presence of TMD painful. Overall, these findings emphasize the importance of considering the psychological stress when judging QST findings.(AU)

Contextualização: Teste sensorial quantitativo (QST) é um método promissor para avaliar os mecanismos que contribuem para o desenvolvimento e manutenção das Disfunções Temporomandibulares (DTM) dolorosas. As respostas de QST dependem da percepção do participante; portanto, uma série de fatores cognitivos e psicológicos, como o estresse, podem influenciar os resultados. Objetivo: Avaliar a influência do estresse psicológico experimental na resposta de QST em pacientes com DTM e voluntários saudáveis. Métodos: 20 mulheres com DTM (Dor Miofascial) e 20 mulheres saudáveis foram submetidas a um protocolo padronizado de QST, incluindo limiar de detecção ao frio (CDT), limiar de detecção ao calor (WDT), limiar de dor ao frio (CPT), limiar de dor ao calor (HPT), limiar de dor mecânica (MPT), limiar de dor a pressão (PPT) e somação temporal de dor (WUR) na região de masseter. QST foi realizado antes e após teste de estresse psicológico laboratorial denominado Paced Auditory Serial Addition Task (PASAT). ANOVA foi realizada para avaliar o efeito de grupo e tempo sobre o estresse relatado e valores de QST a um nível de significância de 5% (p = 0,050). Ademais, perfis Z-score foram gerados. Resultados: PASAT induziu aumento significativo no relato de estresse (p <0,001). Após exposição ao estresse experimental, ambos os grupos apresentaram aumento nos limiares de detecção térmicos (CDT: F = 4,25, p = 0,017 e WDT: F = 4,10, p = 0,020) e redução dos limiares de dor térmicos (CPT: F= 11,2, p <0,001 e HPT: F = 8,13, p <0,001) quando comparados com valores iniciais. Entretanto, o estresse não induziu mudanças significativas em MPT, PPT ou WUR (p> 0,050). Conclusão: O estresse psicológico experimental induz hipoestesia térmica e hiperalgesia térmica na musculatura mastigatória independente da presença de DTM dolorosa. Esses achados enfatizam a importância de considerar o estresse psicológico do particpante ao interpretar os resultados de QST.(AU)