Blockage of the fractalkine pathway reduces hyperalgesia and prevents morphological glial alterations-Comparison between inflammatory and neuropathic orofacial pain in male rats.

This study aimed to evaluate the effects of inhibitors of the fractalkine pathway in hyperalgesia in inflammatory and neuropathic orofacial pain in male rats and the morphological changes in microglia and satellite glial cells (SGCs). Rats were submitted to zymosan-induced arthritis of the temporomandibular joint or infraorbital nerve constriction, and treated intrathecally with a P2 X7 antagonist, a cathepsin S inhibitor or a p-38 mitogen-activated protein kinase (MAPK) inhibitor. Mechanical hyperalgesia was evaluated 4 and 6 h following arthritis induction or 7 and 14 days following nerve ligation. The expression of the receptor CX3 CR1 , phospho-p-38 MAPK, ionized calcium-binding adapter molecule-1 (Iba-1), and glutamine synthetase and the morphological changes in microglia and SGCs were evaluated by confocal microscopy. In both inflammatory and neuropathic models, untreated animals presented a higher expression of CX3 CR1 and developed hyperalgesia and up-regulation of phospho-p-38 MAPK, which was prevented by all drugs (p < .05). The number of microglial processes endpoints and the total branch length were lower in the untreated animals, but the overall immunolabeling of Iba-1 was altered only in neuropathic rats (p < .05). The mean area of SGCs per neuron was significantly altered only in the inflammatory model (p < .05). All morphological alterations were reverted by modulating the fractalkine pathway (p < .05). In conclusion, the blockage of the fractalkine pathway seemed to be a possible therapeutic strategy for inflammatory and neuropathic orofacial pain, reducing mechanical hyperalgesia by impairing the phosphorylation of p-38 MAPK and reverting morphological alterations in microglia and SGCs.

The association between chronotype profile and temporomandibular disorders among college students.

BACKGROUND: Temporomandibular joint disorders (TMDs) are common in young adults, and the link between chronotype profile and TMDs is unclear. OBJECTIVE: This study examined TMD prevalence and chronotype distribution and explored the relationship between chronotype and TMDs in young adults. MATERIALS AND METHODS: A total of 663 students from Sichuan University completed questionnaires. Chronotype profiles were assessed using the Morningness-Eveningness Questionnaire, and TMDs were screened using the Fonseca Memory Index. To validate the findings, 68 TMD patients and 136 controls were enrolled. RESULTS: The prevalence of TMDs was 69.7%, with significant differences among chronotype profiles. The intermediate profile was the most common chronotype. Eveningness profile was associated with higher TMDs prevalence and severity. Muscle pain and side movement difficulty scores were higher in eveningness and intermediate profiles. Female gender (OR 2.345; 95% CI 1.668-3.297) was a TMD risk factor, while morningness profile (OR 0.537; 95% CI 0.297-0.970) was protective. Validation with TMD patients and controls supported these findings, showing higher eveningness profile prevalence in the TMD groups. CONCLUSIONS: TMDs have a high prevalence in college students, chronotype profiles shown to be associated with TMDs. Morningness is the protection factor in TMDs and PT, eveningness is a risk factor for IT.

Baseline masticatory muscles' performance may predict pain relief in temporomandibular disorders.

OBJECTIVES: To compare masticatory muscles' recruitment in patients with temporomandibular disorders and asymptomatic control subjects. To evaluate if the masticatory muscles' recruitment pattern may predict symptoms' improvement after temporomandibular disorders treatment. MATERIALS AND METHODS: Standardized surface electromyography of anterior temporalis and superficial masseters muscles were recorded and compared at baseline in 26 patients with arthrogenous temporomandibular disorders (study group) and 26 asymptomatic subjects (control group). The study group was treated pharmacologically and by means of five arthrocentesis sessions. Pre-, during-, and post-treatment pain and mandibular function were assessed and compared among timepoints. Clinical improvement in terms of pain and mandibular function was correlated with pre-treatment standardized surface electromyography values. RESULTS: Temporomandibular disorders patients showed improved maximum mouth opening and pain during and after treatment with arthrocentesis compared to baseline (T-test p < 0.01). Standardized surface electromyography values were significantly different in temporomandibular disorders subjects compared to controls (T-test p < 0.05). Improvement in pain at rest after treatment was inversely correlated with pre-treatment masseters standardized surface electromyography symmetry (R-coefficient 0.3936; p < 0.05). CONCLUSIONS: Temporomandibular disorders patients showed a different muscular recruitment pattern compared to controls. The lesser the pre-treatment masseters symmetry, the greater the improvement of pain at rest after treatment.

Efficacy of High-intensity laser therapy in patients with temporomandibular joint disorders: A systematic review and meta-analysis.

This study aimed to assess the effects of High-intensity laser therapy (HILT) on individuals suffering from temporomandibular joint disorders (TMDs). A search was conducted across six electronic databases for randomized controlled trials (RCTs) focusing on HILT for TMDs: PubMed, Scopus, Web of Science, ScienceDirect, EBSCOhost, Cochrane Library, the PEDro database and Google Scholar (last updated on July 18, 2024). Eligible studies were chosen by independent reviewers, and their quality was assessed with the Cochrane risk of bias tool (RoB). The main outcome was pain intensity (VAS), with secondary outcomes including mouth opening (mm), disability (JFLS-20), and quality of life (OHIP-14). A meta-analysis was conducted to assess the pooled effect by calculating mean differences (MD) for these variables (95% confidence level). The heterogeneity of the meta-analyses was explored using the I2 statistic. Three studies met the selection criteria and were included in the meta-analysis. The main RoB was the blinding of participant and treaters. Statistically significant differences (p < 0.05) in favor of HILT were observed for VAS and maximum mouth opening. The pooled effect showed an MD of -14.8 mm (95% CI:-27.1,-2.5) for pain intensity and 3.7 mm (95% CI:0.9,6.5) for mouth opening, changes that were assessed as clinically important. According to GRADE, the evidence was rated as important, and the certainty was moderate due to the heterogeneity between studies. A sensitivity analysis was not performed to address heterogeneity, primarily due to the limited availability of RCTs. HILT has been found effective in short-term pain relief and improvement of jaw opening in TMDs, potentially enhancing quality of life by facilitating activities such as chewing, jaw mobility, and communication. However, further research is needed to confirm its long-term effectiveness. Combining HILT with interventions such as occlusal splints or therapeutic exercises could potentially enhance its effects, leveraging the existing evidence supporting these treatments. It is important to note that the high RoB associated with the lack of blinding of participants and treaters may influence data collection, compromising the internal validity of findings in some studies.

Effectiveness of photobiomodulation and orofacial myofunctional therapy in orofacial pain disorders. A systematic review of randomized control trials.

Orofacial pain can significantly affect physical, psychological, and overall quality of life. This study aimed to compare the effectiveness of combining photobiomodulation (PBM) with orofacial myofunctional therapy (OMT) in managing orofacial pain disorders. An electronic search of randomized controlled trials in electronic databases was performed until March 2024. Randomized controlled trials (RCTs) focusing on PBM and OMT for the management of orofacial pain were included. Risk of bias across individual studies was performed using the Cochrane risk of bias tool for interventions. A total of 10 RCTs were included, out of which 7 RCTs revealed that the combined approach of PBM and OMT had a more pronounced impact on diminishing pain and enhancing functional activity in patients with orofacial disorders. One study reported significant increases in pressure pain threshold for TMJ, masseter, and anterior temporalis muscles at both sides in the post-treatment compared with the pre-treatment in both groups. The risk of bias was low in 7, moderate in 2, and high in 1 study. The efficacy of a combined modality treatment of PBM with OMT for orofacial pain disorder shows promising results. However, further randomized controlled trials with extended follow-up periods standardized PBM and OMT parameters are warranted to obtain firm conclusions.

Exploring the causal effects of sleep characteristics on TMD-related pain: a two-sample Mendelian randomization study.

OBJECTIVES: The study was to explore the causal effects of sleep characteristics on temporomandibular disorder (TMD)-related pain using Mendelian randomization (MR) analysis. MATERIALS AND METHODS: Five sleep characteristics (short sleep, insomnia, chronotype, snoring, sleep apnea) were designated as exposure factors. Data were obtained from previous publicized genome-wide association studies and single nucleotide polymorphisms (SNPs) strongly associated with them were utilized as instrumental variables (IVs). TMD-related pain was designed as outcome variable and sourced from the FinnGens database. MR analysis was employed to explore the causal effects of the five sleep characteristics on TMD-related pain. The causal effect was analyzed using the inverse variance-weighted (IVW), weighted median, and MR-Egger methods. Subsequently, sensitivity analyses were conducted using Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests. RESULTS: A causal effect of short sleep on TMD-related pain was revealed by IVW (OR: 1.60, 95% CI: 1.06-2.41, P = 0.026). No causal relationship was identified between other sleep characteristics (insomnia, chronotype, snoring, sleep apnea) and TMD-related pain. CONCLUSIONS: Our study suggests that short sleep may increase the risk of TMD-related pain, while there was no causal relationship between other sleep characteristics and TMD-related pain. Further studies are warranted to deepen and definitively clarify their relationship. CLINICAL RELEVANCE: These findings reveal that the short sleep may be a risk factor of TMD-related pain and highlight the potential therapeutical effect of extending sleep time on alleviating TMD-related pain.

Influence of malocclusion on sleep bruxism and orofacial pain: data from a study in school children.

OBJECTIVES: This cross-sectional school-based study explored the influence of malocclusion on temporomandibular disorders (TMD) pain complaints, and whether this association would be mediated by sleep bruxism in a representative sample of 7- to 8-year-old children. METHODS: Path analysis estimated direct, indirect, and total effects of occlusal features on sleep bruxism and TMD pain in 7- to 8-year-old children. Occlusal features were assessed with Dental Aesthetic Index (DAI), orofacial pain complaints using the TMD pain screener, possible sleep bruxism based on self-reports, and probable sleep bruxism based on self-reports combined with clinical findings. Structural equation modeling analyzed data with confounding factors. RESULTS: From 580 participants, possible sleep bruxism was observed in 136 children (31.5%), probable sleep bruxism in 30 children (6.7%), and TMD pain complaints in 78 children (13.8%). Malocclusion had no direct effect on either possible sleep bruxism [standardized coefficient (SC) 0.000; p = 0.992], or TMD pain complaints (SC - 0.01; p = 0.740). When probable sleep bruxism was set as the mediator of interest, malocclusion did not directly affect probable sleep bruxism (SC 0.01; p = 0.766), nor TMD pain complaints (SC - 0.02; p = 0.515). A direct effect of probable sleep bruxism on TMD pain complaints was observed with an SC of 0.60 (p < 0.001). However, in neither case, malocclusion indirectly affected TMD pain complaints via bruxism. CONCLUSION: Malocclusion in 7- to 8-year-old children did not directly influence possible or probable sleep bruxism or TMD pain complaints. Instead, probable sleep bruxism was strongly associated with TMD pain complaints. CLINICAL SIGNIFICANCE: The impact of occlusal features on TMD pain complaints and bruxism has been a long-standing controversy in dentistry. However, the scientific literature linking this association may be inconsistent, mainly due to biased sample selection methods with inadequate consideration of confounders. Further research should try to identify additional risk factors for TMD pain in addition to probable sleep bruxism in children.

Self-reported bruxism in patients with post-traumatic stress disorder.

OBJECTIVE: The present study aimed to investigate the association between self-reported awake/sleep bruxism, and orofacial pain with post-traumatic stress disorder (PTSD). METHODS: A case-control study with a convenience sample was designed. Participants were recruited from a university-based Trauma Ambulatory. The diagnosis of PTSD was established through a clinical interview and the Structured Clinical Interview (SCID-I/P). Thirty-eight PTSD patients and 38 controls completed the Research Diagnostic Criteria for Temporomandibular Disorders Axis-II to categorize awake/sleep bruxism and orofacial pain. Following this, we performed a short clinical examination of the temporomandibular joint and extraoral muscles. RESULTS: Adjusted logistic regression analysis showed that awake bruxism was associated with PTSD (OR = 3.38, 95% CI = 1.01-11.27, p = 0.047). Sleep bruxism was not associated with any covariate included in the model. In a Poisson regression model, PTSD (IRR = 3.01, 95% CI = 1.38-6.55, p = 0.005) and the muscle pain/discomfort (IRR = 5.12, 95% CI = 2.80-9.36, p < 0.001) were significant predictors for current orofacial pain. CONCLUSIONS: PTSD was associated with self-reported awake bruxism and low-intensity orofacial pain. These conditions were frequent outcomes in patients previously exposed to traumatic events. CLINICAL RELEVANCE: We suggest including a two-question screening for bruxism in psychiatry/psychology interviews to improve under-identification and to prevent harmful consequences at the orofacial level.

Relationships between functional temporomandibular joint space and disc morphology, position, and condylar osseous condition in patients with temporomandibular disorder.

OBJECTIVE: To investigate the correlations between joint space and temporomandibular joint (TMJ) components and the compressive states of the disc and condyle subsequent to joint space changes. MATERIALS AND METHODS: A total of 240 TMJs were categorized according to disc morphology, disc position, and condylar osseous condition. The two-dimensional (2D) and three-dimensional (3D) measurements were compared. The functional joint space (FJS) and disc areas on closed- and open-mouth images (DA-C and DA-O) were also calculated, and the joint space was measured in five directions. Different groups of TMJ components were compared. A spring model was used to simulate the effect of condylar displacement on the disc and condyle. RESULTS: Disc morphology was strongly correlated with its position. The measurements were equivalent between 2D and 3D methods. DA-C and FJS differed significantly between groups. The DA-C to FJS ratio differed between the Class 2 and Class 3 groups and between disc displacement groups with and without reduction. Altered disc morphology and position were correlated with significant changes in joint space in the 60°, 90°, and 120° directions. Despite minor discrepancies among condylar osseous conditions, reduced joint space was correlated with bone destruction at the corresponding site. The spring model stimulation revealed that condylar displacement caused elevated stresses on the disc and condyle. CONCLUSIONS: Condylar displacement causes joint space alterations while exerting compressive pressure on both the disc and condyle. CLINICAL RELEVANCE: Proper condylar positioning within the fossa is recommended to ensure sufficient articular disc accommodation.

Genetic change investigation in DOCK1 gene in an Iranian family with sign and symptoms of temporomandibular joint disorder (TMD).

OBJECTIVES: Temporomandibular joint disorder (TMD) is a complex condition with pain and dysfunction in the temporomandibular joint and related muscles. Scientific evidence indicates both genetic and environmental factors play a crucial role in TMD. In this study, we aimed to discover the genetic changes in individuals from 4 generations of an Iranian family with signs and symptoms of TMD and malocclusion Class III. MATERIALS AND METHODS: Whole Exome Sequencing (WES) was performed in 4 patients (IV-8, IV-9, V-4, and V-6) with TMD according to (DC/TMD), along with skeletal Class III malocclusion. Then, PCR sequencing was performed on 23 family members to confirm the WES. RESULTS: In the present study, WES results analysis detected 6 heterozygous non-synonymous Single Nucleotide Variants (SNVs) in 5 genes, including CRLF3, DNAH17, DOCK1, SEPT9, and VWDE. A heterozygous variant, c.2012T > A (p.F671Y), in Exon 20 of the DOCK1 (NM_001290223.2) gene was identified. Then, this variant was investigated in 19 other members of the same family. PCR-Sequencing results showed that 7/19 had heterozygous TA genotype, all of whom were accompanied by malocclusion and TMD symptoms and 12/19 individuals had homozygous TT genotype, 9 of whom had no temporomandibular joint problems or malocclusion. The remaining 3 showed mild TMD clinical symptoms. The 5 other non-synonymous SNVs of CRLF3, DNAH17, SEPT9, and VWDE were not considered plausible candidates for TMD. CONCLUSIONS: The present study identified a heterozygous nonsynonymous c.2012T > A (p.F671Y) variant of the DOCK1 gene is significantly associated with skeletal class III malocclusion, TMD, and its severity in affected individuals in the Iranian pedigree. CLINICAL RELEVANCE: The role of genetic factors in the development of TMD has been described. The present study identified a nonsynonymous variant of the DOCK1 gene as a candidate for TMD and skeletal class III malocclusion in affected individuals in the Iranian pedigree.

Mechanical and biological properties of polymer materials for oral appliances produced with additive 3D printing and subtractive CAD-CAM techniques compared to conventional methods: a systematic review and meta-analysis.

OBJECTIVES: The aim of this review was to analyze mechanical and biological properties of resin materials used with subtractive or additive techniques for oral appliances fabrication and compare them to those conventionally manufactured. MATERIALS AND METHODS: The protocol was registered online at Open Science Framework (OSF) registries ( https://osf.io/h5es3 ) and the study was based on the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P). An electronic search was conducted on MEDLINE (via PubMed), Scopus, and Web of Science from 1 February 2022 to 1 May 2022. INCLUSION CRITERIA: in vitro and in vivo studies published in the last 10 years, with CAD-CAM or 3D printed resins for occlusal splints. Data considered homogenous were subjected to meta-analysis (95% confidence interval [CI]; α = 0.05) with Stata17 statistical software. Since all variables were continuous, the Hedge g measure was calculated. A fixed-effects model was used for I2 = 0%, while statistical analysis was conducted using a random-effects model with I2 > 0%. RESULTS: 13 studies were included after full-text reading. The mechanical properties most studied were wear, flexural strength, surface hardness and surface roughness, while only 1 study investigated biological properties, performing the XTT viability assay. For the meta-analysis, only surface roughness, volume loss, and flexural strength were selected. Considering surface roughness, the subtractive specimen had a lower average value compared to traditional ones (Hedge's g with 95% CI = -1.25[ -1.84, - 0.66]). No significant difference was detected in terms of volume loss (P > 0.05) between the groups (Hedge's g with 95% CI = -0.01 [-2.71, - 2.68]). While flexural strength was higher in the control group (Hedge's g with 95% CI = 2.32 [0.10-4.53]). CONCLUSION: 3D printed materials showed properties comparable to conventional resins, while milled splint materials have not shown better mechanical performance compared with conventional heat-cured acrylic resin. Polyetheretherketone (PEEK) have great potential and needs to be further investigated. Biological tests on oral cell populations are needed to confirm the long-term biocompatibility of these materials. CLINICAL RELEVANCE: The use of "mixed splints" combining different materials needs to be improved and evaluated in future research to take full advantage of different characteristics and properties.

Ultrasonographic characteristics of myogenous temporomandibular disorders: A scoping review.

OBJECTIVE: To identify the available evidence on the ultrasonographic characteristics of masticatory muscles in subjects with myogenous TMD, as well as the potential use of ultrasonography as a diagnostic and treatment assessment outcomes tool. METHOD: An electronic search of the PubMed, Web of Science and Scopus databases was performed using the following terms: 'ultrasonography', 'ultrasound', 'masseter', 'temporal', 'masticatory muscles', 'temporomandibular disorders', 'temporomandibular joint disorders'. Full-text articles were obtained from the records after applying the inclusion/exclusion criteria. RESULTS: Thirteen articles were included for analysis: one comparative cross-sectional study, five case-control studies, six clinical trials and one randomised clinical trial. Main ultrasonographic characteristic assessed were local cross-sectional dimension and intramuscular ultrasonographic appearance. Retrieved studies reported the use ultrasonography for diagnosis or treatment assessment purposes showing heterogeneous results. For diagnosis purposes, the results of local cross-sectional dimension are not consistent; therefore, its diagnostic value for myogenous TMD diagnosis is weak. However, more homogeneous results were observed for intramuscular ultrasonographic appearance showing a higher prevalence of type-II pattern in myogenous TMD subjects than non-TMD subjects. On the other hand, for treatment assessment purposes, muscles were observed thinner after treatment compared to pre-treatment. Also, results of intramuscular ultrasonographic appearance show disappearance or reduction of anechoic areas, higher prevalence of type-II pattern and significant distinction of echogenic bands were observed after treating TMD subjects. CONCLUSION: Ultrasonography cannot be considered as a diagnostic instrument, but maybe as a complementary tool for treatment assessment of myogenous TMD subjects, even though future research is required to confirm its utility.

Telediagnosis as an effective tool for assessment temporomandibular disorders.

BACKGROUND: The use of communication technologies has allowed a substantial improvement in telediagnosis. OBJECTIVES: To evaluate the feasibility and diagnostic agreement of synchronous teleconsultation compared to physical standard examination for temporomandibular disorders (TMD) and orofacial pain. METHODS: Sixty-one patients (50 women, 11 men) with a mean age of 46.07 years referred to the Orofacial Pain Ambulatory Service (SAMDOF -UFPR) were evaluated remotely. They were then examined in person by another evaluator, blinded for the first evaluation. Data on the experience and level of satisfaction with the teleconsultation were also collected. RESULTS: For each type and subtype of TMD, diagnostic agreement values, sensitivity, specificity, positive predictive values and negative predictive values were calculated with a 95% confidence interval. 'Almost perfect' agreement was found for Myalgia (k = 0.915), Arthralgia (k = 0.863), disc displacement without reduction without limited opening (k = 0.955) and no TMD (k = 1.00). 'Substantial' agreement for the subtypes headache attributed to TMD (k = 0.761), disc displacement without reduction with limited opening (k = 0.659) and subluxation (k = 7.82). The diagnoses of local myalgia (k = 0.573), myofascial pain with referral (k = 0.524) and disc displacement with reduction (k = 0.563) obtained 'moderate' agreement. Degenerative joint disease (k = 0.170) and disc displacement with reduction with intermittent locking (k = 0.000) obtained 'weak' and 'no agreement', respectively. More than 90% of the participants were satisfied and reported no discomfort during the assessment, agreeing to participate in another teleconsultation. CONCLUSION: Synchronous teleconsultation proved to be feasible and presented adequate diagnostic agreement for the main painful TMDs, especially for the diagnosis of myalgia and arthralgia. This format was also well accepted among patients.

A global bibliometric analysis on the relationship between tinnitus and temporomandibular disorders.

BACKGROUND AND OBJECTIVES: This global bibliometric review aimed to investigate trends in publications relating to tinnitus and TMD. METHODS: A search was performed in eight databases (June/2022), by independent researchers with relevant keywords about tinnitus and TMD, without restriction of date or language. Original research or case report/series evaluating prevalence, association and risk related to tinnitus and TMD were included. Independent examiners selected studies by title and abstract and performed data extraction. Data about publication and researchers, study population, objective, study design and diagnostic criteria for tinnitus and TMD were exported to VintagePoint® for bibliometric analyses. Data about the direct association between tinnitus and TMD were extracted. RESULTS: One hundred and seventeen articles from 25 countries were included, most observational (68.4%) and evaluating association (N = 60; 44.8%). Among the 60 studies of association, 22 (36.6%) presented results of a direct association between the presence/absence of tinnitus and the presence/absence of TMD. Brazil (19.5%) and the United States (12.7%) were the countries with the most publications, and Dentistry (48.6%) was the main publication area. A growth in publications in Dentistry was observed in the past 30 years and in the past 10 years in Medicine. Half of the studies included the elderly population (50.2%). The main diagnostic criterion for both tinnitus (37.8%) and TMD (28%) was general questionnaires and/or self-report. CONCLUSION: There is a growing trend in publications relating to tinnitus and TMD, especially in Dentistry, with a predominance of observational and association studies in the elderly population using questionnaires and/or self-report. More research with robust diagnostic methods and other study designs should be encouraged in the future.

The application of extracorporeal shock wave therapy in the treatment of temporomandibular joint disorders in a preliminary, small sample study.

OBJECTIVE: The aim of this study was to investigate the efficacy of low-intensity, high-frequency shock waves in the treatment of temporomandibular joint disorders. METHODS: Twenty-six patients with temporomandibular joint disorder admitted to the Second Hospital of Shanxi Medical University from August 2022 to December 2022 were selected as study subjects and randomly divided into two groups, A and B, with 13 patients each. In Group A, there were 5 males and 8 females with an average age of 38.85 ± 11.03 years. In Group B, there were 4 males and 9 females with an average age of 39.15 ± 11.16 years. Group A was the control group, which received routine treatment (manual massage + transcutaneous electrical nerve stimulation + ultrashort wave therapy) plus sham shock wave therapy; Group B was the experimental group, which received routine treatment (manual massage + transcutaneous electrical nerve stimulation + ultrashort wave therapy) plus shock wave therapy. The routine treatment was administered once/day, five times per week for a total of 2 weeks of treatment. In addition, shock wave therapy was administered once every 5 days, and the treatment was administered three times. The treatment period was 2 weeks, and the two groups were compared before treatment, at the end of the treatment period, and 4 weeks after treatment. The pain level of the two groups was assessed by the visual analogue scale (VAS) before and after treatment, and the temporomandibular opening index (TOI) before and after treatment was compared between the two groups. VAS and TOI scores were evaluated using the Mann-Whitney U-test, the Kruskal-Wallis H-test and two-way ANOVA. RESULTS: There was no significant difference in the VAS score and temporomandibular opening index between the two groups before treatment (p = .829 and .75, respectively). After 2 weeks of treatment, the VAS score and temporomandibular joint opening index of both groups were significantly improved compared to those before therapy. In addition, the VAS score and temporomandibular joint opening index in the experimental group were significantly better than those in the control group (p < .001 and <.001, respectively). There was a small increase in scores 4 weeks after the treatment compared to just after the treatment period, but the difference was not significant. CONCLUSION: This is a preliminary small sample study that demonstrates the positive effect of using low-intensity, high-frequency shock waves on the treatment of temporomandibular joint disorders and is worthy of clinical promotion.

Nutrition and chronic musculoskeletal pain: A narrative review and directions for temporomandibular disorder research and management.

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.

Clinical features of chronic primary pain in individuals presenting painful temporomandibular disorder and comorbidities.

BACKGROUND: The diagnosis of chronic primary pain (CPP), according to the recently released International Classification of Disease (ICD-11) criteria, refers to conditions with complex aetiologies. CPP is characterized by specific clinical features such as generalized sensory hypersensitivity and widespread pain, and is associated with functional disability and emotional distress. OBJECTIVE: This study investigated clinical features of CPP in individuals with painful temporomandibular disorders (TMD) and comorbidities (fibromyalgia, migraine and/or tension-type headache). METHODS: This cross-sectional study was conducted with a sample of 129 individuals. Painful TMD, fibromyalgia and primary headaches were evaluated based on well-established international criteria. Generalized sensory hypersensitivity was assessed using psychophysical tests. Symptoms of anxiety and depression were assessed by the Generalized Anxiety Disorder-7 and Patient Health Questionnaire-9. The Central Sensitization Inventory was applied to assess central sensitization-related symptoms and the Pittsburg Sleep Quality Index to evaluate the quality of sleep. The presence of widespread pain was assessed using a body map. The sample was stratified into three groups: control (n = 25), TMD-painful TMD only (n = 35) and TMD + Cm-painful TMD and comorbidities (n = 69). Statistical analysis was performed using one-way ANOVA, chi-squared test and ANCOVA, considering gender as a covariate (α = .05). RESULTS: Compared to controls, individuals presenting painful TMD and comorbidities showed lower pressure pain thresholds in all evaluated areas (p ≤ .012) and a higher number of painful areas in the body (p = .001). They presented more symptoms of anxiety (p = .040) and depression (p = .018), and a higher score in the Central Sensitization Inventory (p ≤ .006) than the other groups. CONCLUSION: Individuals with painful TMD and comorbidities presented more clinical features of CPP compared to those affected by TMD only.

The bruxism screener (BruxScreen): Development, pilot testing and face validity.

BACKGROUND: To assess awake and sleep bruxism, the Standardised Tool for the Assessment of Bruxism (STAB) is currently being developed. The STAB will be a comprehensive tool for the detailed assessment of bruxism behaviour itself as well as of its possible consequences, causes, and comorbid conditions. OBJECTIVE: Since the STAB cannot fully meet the 'A4 principle' for a bruxism assessment tool, i.e., being Accurate (reliable and valid), Applicable (feasible), Affordable (cost-effective), and Accessible (suitable for everyday clinical use), the Bruxism Screener (BruxScreen) has been developed to be used in large-scale epidemiological research projects and, especially, in general, dental practices. METHODS: The BruxScreen consists of two parts: a questionnaire (BruxScreen-Q) to be completed by patients, and a clinical assessment form (BruxScreen-C) to be completed by dentists. RESULTS: This paper describes the development of the BruxScreen and provides the outcomes of the pilot testing phase and the face validity assessment (i.e. that the first impressions of the tool indicate that it adequately reflects the construct to be measured). CONCLUSION: The resulting BruxScreen is considered ready for more profound psychometric testing in the general dental setting.

Conceptualising TMD symptom burden in youths: Symptom duration, frequency, intensity and interference.

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 (rs = .50-.88). While TS burden and GS were weakly associated with psychological distress (rs = .18-.36), SS burden was moderately related to depression, anxiety and stress (rs = .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.

Oral habits and temporomandibular joint disorders according to stress levels among military personnel in South Korea: A cross-sectional study.

BACKGROUND: Military personnel suffer from stress-induced temporomandibular joint disorders (TMD). No previous studies have evaluated the oral habits and TMD in military personnel based on their stress levels. OBJECTIVES: To examine the correlation between oral habits and TMD based on stress levels. In addition, we assessed the relationship between stress levels and TMD by military rank as well as the impact of oral habits on TMD. METHOD: This cross-sectional survey included 89 military personnel who visited the Armed Forces Medical Center in Korea with discomfort in the temporomandibular joint (TMJ) discomfort. Oral habits, stress level, TMD and general characteristics of the subjects were investigated. A questionnaire was distributed to the subjects who agreed to the study, and they were asked to respond in a self-written form. Multiple linear regression analysis was performed to examine the factors that affect oral habits and TMJ symptoms. RESULTS: Stress scores and oral habits were highest in the 'Private' rank. In contrast, temporomandibular joint symptoms were highest in the 'Corporal' rank. Additionally, the high-risk stress group exhibited higher scores in oral habits and TMD compared to the potential stress group. Furthermore, there was a positive correlation between an increase in high-risk stress scores and a rise in oral habits. And individuals with more oral habits are at an increased likelihood of experiencing TMD. CONCLUSION: Our study findings suggest that military personnel with prevent TMD and improve oral habits by addressing stress levels.