Temporomandibular Disorders and Orthodontics: how to conduct a screening examination? / Dysfonctionnements temporo-mandibulaires et orthodontie : comment conduire un examen de dépistage ?

Introduction: Common Temporomandibular Disorders (TMD) involve the masticatory muscles, temporomandibular joints, and/or their associated structures. Clinical manifestations can vary, including sounds (cracking, crepitus), pain, and/or dyskinesias, often corresponding to a limitation of mandibular movements. Signs or symptoms of muscular or joint disorders of the masticatory system may be present before the initiation of orthodontic treatment, emerge during treatment, or worsen to the point of stopping treatment. How do you screen for common TMD in orthodontic treatment? Materials and Methods: The main elements of the interview and clinical examination for screening common TMD in the context of orthodontic treatment are clarified and illustrated with photographs. Moreover, complementary examinations are also detailed. Results: A clinical screening form for common TMD is proposed. A synthetic decision tree helping in the screening of TMD is also presented. Conclusion: In the context of an orthodontic treatment, the screening examination for common TMD includes gathering information (interview), a clinical evaluation, and possibly complementary investigations. The orthodontist is supported in this approach through the development of a clinical form and a dedicated synthetic decision tree for the screening of TMDs. Systematically screening for common TMD before initiating orthodontic treatment allows the orthodontist to suggest additional diagnostic measures, implement appropriate therapeutic interventions, and/or refer to a specialist in the field if necessary.

Introduction: Les dysfonctionnements temporo-mandibulaires (DTM) concernent les muscles masticateurs, les articulations temporo- mandibulaires et/ou leurs structures associées. Les manifestations cliniques peuvent être diverses : bruits (craquements, crépitements), algies et/ou dyscinésies correspondant le plus souvent à une limitation des mouvements mandibulaires. Or, des signes ou symptômes de troubles musculaires ou articulaires de l'appareil manducateur peuvent être présents avant le début de la prise en charge orthodontique, voire apparaître en cours de traitement ou s'aggraver au point de remettre en question la poursuite du traitement engagé. Comment conduire un dépistage de DTM communs dans le cadre d'une prise en charge orthodontique ? Matériel et méthodes: Les éléments essentiels de l'entretien et de l'examen clinique d'un dépistage des DTM communs dans le cadre d'une consultation d'orthodontie sont clarifiés et illustrés à l'aide de photographies. Le recours aux examens complémentaires a également été détaillé. Résultats: Une fiche clinique de dépistage des DTM communs est proposée. Un arbre décisionnel synthétique aidant au dépistage des DTM est présenté. Conclusion: Dans le cadre d'une consultation d'orthopédie dento-faciale, l'examen de dépistage des DTM communs inclut un recueil d'informations (entretien), une évaluation clinique et éventuellement des examens complémentaires. L'orthodontiste est soutenu dans cette démarche par la création d'une fiche clinique et d'un arbre décisionnel synthétique dédiés au dépistage des DTM. Effectuer systématiquement un dépistage des DTM communs avant d'initier un traitement orthodontique permettra à l'orthodontiste de proposer des moyens diagnostiques supplémentaires si nécessaire, et de mettre en place la prise en charge adéquate et/ou de référer à un spécialiste du domaine pour démarrer le traitement orthodontique dans les meilleures conditions.

Sleeping and waking-state oral behaviors in TMD patients: their correlates with jaw functional limitation and psychological distress.

OBJECTIVES: This study investigated oral behaviors in various temporomandibular disorder (TMD) subtypes, assessing their frequency, extent, and associations with both jaw functional status and psychological distress. MATERIALS AND METHODS: Anonymized data from consecutive "initial-visit" TMD patients at a university-affiliated oral medicine clinic were obtained. Alongside demographic information, patients completed various questionnaires including the Diagnostic Criteria for TMD (DC/TMD) Symptom Questionnaire, Oral Behavior Checklist (OBC), Jaw Functional Limitation Scale-20 (JFLS-20), Patient Health Questionnaire-9 (PHQ-9), and General Anxiety Disorder Scale-7 (GAD-7). Patients underwent a protocolized clinical examination and received diagnoses of pain-related (PT), intra-articular (IT), or combined (CT) TMD using the DC/TMD diagnostic algorithms. Data were evaluated with Chi-square/non-parametric tests and logistic regression analyses (α = 0.05). RESULTS: The study comprised 700 patients (mean age 37.4 ± 15.7 years), with 12.6%, 15.1%, and 72.3% diagnosed with PT, IT, and CT, respectively. For all TMD subtypes, oral activities during sleep were more prevalent than those during wakefulness. While variations in total/subscale OBC scores were insignificant, substantial differences were observed in global/subscale JFLS (PT, CT > IT), depression (PT, CT > IT), and anxiety (CT > IT) scores. Near-moderate correlations (rs = 0,36-0.39) were discerned between overall/waking-state non-functional oral behaviors and depression/anxiety. Multivariate analysis indicated that the odds of different TMD subtypes were influenced by sex, age, and jaw functional status. CONCLUSIONS: For all TMD patients, sleep-related oral activities were more commonly reported than waking-state activities. Factors such as sex, age, and jaw functional limitation are associated with the likelihood of different TMD subtypes. STATEMENT OF CLINICAL RELEVANCE: Oral behaviors, in themselves, do not predict distinct TMD subtypes, in contrast to factors such as sex, age, and jaw functional status.

Physical therapy in addition to occlusal splint in myogenic temporomandibular disorders: A randomised controlled trial.

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 [CI95%: -2.67, -0.32], p = .04; VAS open = -2.00 cm [CI95%: -3.23, -0.75], p < .01; VAS chew = -1.71 cm [CI95%: -2.90, -0.52], p = .01; ROM = 4.61 [CI95%: 0.93, 8.30], p = .04). Additionally, VAS measures were influenced by follow-up times (VAS rest = -0.73 cm [CI95%: -1.30, -0.17], p = 0.03; VAS open = -0.97 cm [CI95%: -1.57, -0.37], p < .01; VAS chew = -1.15 cm [CI95%: -1.73, -0.58], p < .01). At T1, EG demonstrated higher number of responders compared to CG for VAS open (χ2(1) = 4.39, p = .04) and VAS chew (χ2(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.

Putting science to work for women's health.

The Office of Research on Women's Health (ORWH)'s whole health paradigm expands the scope of women's health research, incorporating a life-course perspective that recognizes the profound influences of sex and gender on health. From childhood through adulthood, external and societal factors along with internal factors and biology shape women's health and influence access to quality healthcare. This comprehensive approach integrates data-driven sex- and gender-aware strategies to prevent, diagnose, and treat disease, focusing on the unique needs of women. Acknowledging the historical lack of timely research and data on women's health, an initiative led by First Lady Dr. Jill Biden and the White House Gender Policy Council, ushers in a new era of women's health research that offers unprecedented opportunities to enhance the health of women through biomedical and behavioral research. The initiative fosters interdisciplinary collaboration, supporting research on autoimmune diseases, menopause, oral health, and chronic pain conditions. ORWH serves as the focal point for National Institutes of Health (NIH) women's health research. With a commitment to advancing holistic outcomes, ORWH engages in partnerships, outreach, and educational initiatives to disseminate critical research findings and support women's health researchers. Here we describe the convergence of this initiative with the National Institute of Dental and Craniofacial Research's work to advance the understanding of sex as a biological variable for conditions such as Sjogren's disease and temporomandibular disorder. This transformative approach to women's health research propels the United States toward innovative solutions, ensuring that science works for the health and well-being of every woman.

Voice quality in patients with temporomandibular disorders.

OBJECTIVES: This study assessed the voice quality in TMD patients compared to healthy individuals using the Dysphonia Severity Index (DSI) and evaluated the correlation between the DSI and TMD severity. METHODS: Patients who had TMD with Fonseca's anamnestic index were subjected to an examination based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). A sample of 35 patients with TMD and 36 healthy subjects were included in the study. RESULTS: There were significant differences in the DSI score and its components between healthy subjects and TMD patients (p < .001). A significant correlation was found between the DSI scores and TMD severity (Spearman's rho: -0.90, p < .001). CONCLUSION: Patients with TMD demonstrated lower DSI scores and lower voice quality compared to healthy subjects.

Morphological and morphometric measurement of the temporomandibular joint of small and medium-weight dogs with different skull shapes.

Background: The recognition and diagnosis of canine temporomandibular joint (TMJ) disease can be a challenge, often leaving them undiagnosed. Although computed tomography (CT) has proved to be highly efficacious in detecting joint disease in the TMJ, morphometric and morphological studies of the normal TMJ have been scarce. Especially, skull type specific anatomical differences of the TMJ in dogs of different weights and skull morphologies have received limited attention. Objective: This study aimed to compare the TMJ morphologies of dogs across different weight classes and skull types. Study design: Retrospective study. Methods: CT scans were used to measure the depth and width of the Fossa mandibularis and two angles between the Fossa mandibularis and the Caput mandibulae in a total of 92 dogs and 182 mandibular joints, respectively. Results: The TMJ varied in terms of weight groups and skull indices. Shallow mandibular pits, underdeveloped retroarticular processes, and reduced joint congruency were observed particularly in light-weight and brachycephalic dogs. Conversely, dolichocephalic animals displayed deep joint pits, pronounced joint congruency, and a well-developed Processus retroarticularis. Main limitations: Observer learning curve; not every skull shape was represented in each weight group.

Impact of Orthodontic-Surgical Treatments on the Signs and Symptoms of Temporomandibular Disorders: A Systematic Review.

INTRODUCTION: Some patients exhibit temporomandibular joint or muscular disorders of the masticatory system before, during, or after orthognathic surgery (OS). These are collectively referred to as temporomandibular disorders (TMDs). This systematic literature review aimed to determine the relationship between orthodontic-surgical treatment and TMDs. METHODS: An electronic search of the PubMed database, supplemented by a manual search, was performed; the search included any studies published between 2021 (date of the last search in a systematic review of the literature on the subject) and June 2023 that evaluate the prevalence of TMDs during orthodontic-surgical treatment. The diagnosis of TMDs had to be established using the diagnostic algorithm "diagnostic criteria for temporomandibular disorders (DC/TMDs)", and the diagnosis of disc displacement had to be confirmed using magnetic resonance imaging (MRI). The data were extracted and statistically analyzed. RESULTS: Of the 100 results, seven eligible articles were included, representing a total of 529 cases undergoing orthodontic-surgical treatment. A reduction in joint noises (64.8%), arthralgia (57 to 77%), and myalgia (73 to 100%) was found after orthodontic-surgical treatment despite the fact that a minority of patients exhibited these signs and symptoms even though they were asymptomatic before treatment. The effects of OS on disc position were objectively unpredictable. After surgery, the presence of headaches decreased without significance and the risk of their occurrence was very low (1%). The studies converged toward a reduction in the amplitudes of mouth opening and lateral/protrusion movements. Finally, after the treatment, mandibular function was improved. CONCLUSION: Under the conditions of this study, OS seems to have a positive impact on the signs and symptoms of TMDs; however, it is not possible to predict the consequential effects on the position of the TMJ disc, whether it is initially in a normal position or displaced.

Use of antidepressants in the treatment of chronic orofacial pain caused by temporomandibular disorders: A randomized controlled clinical trial.

BACKGROUND AND OBJECTIVE: Temporomandibular disorders (TMDs) are a common pathology, associated with pain in the facial territory and with associated psychological disorders, such as anxiety and depression. The aim of this study was to evaluate the efficacy of antidepressants in the treatment of pain associated with TMD. MATERIALS AND METHODS: Sixty four patients suffering from chronic orofacial pain, randomly distributed in 3 groups: control group treated with night splint, group treated with 10mg/day of citalopram and group treated with 25mg/day of amitriptyline. Pain intensity was assessed, randomly, by a single blinded evaluator, according to the VAS at baseline and after one, three, six and nine weeks. RESULTS: All groups showed a reduction of pain throughout the period of time evaluated, however, the group treated with amitriptyline showed the best pain reduction results 3.3±1.5, 1.5±1.4 and 0.9±1.3 at 3, 6 and 9 weeks, respectively. CONCLUSIONS: Low doses of amitriptyline appear to be a good therapeutic option in patients with TMDs suffering from chronic orofacial pain.

Synthesis of temporomandibular disorders management intervention outcomes for development of core outcome sets: A systematic review.

INTRODUCTION: The selection of appropriate outcomes in clinical trials and systematic reviews is a crucial factor in determining the results that are useful, reliable, and relevant for both patients and healthcare professionals. Clinicians and researchers have been encouraged to develop and apply core outcome sets (COS) to minimise the discrepancy between studies. AIM: This systematic review is the first phase of the COS development project for clinical trials in temporomandibular disorders (COS-TMD). It aims to identify and synthesise the outcomes used in the randomised controlled trials (RCT) that evaluated the effectiveness of interventions used in TMD management. MATERIALS AND METHODS: An electronic search was performed in several databases: MEDLINE (via PubMed), Scopus, Web of Science, Cochrane Library and EMBASE. The eligibility criteria comprised RCT that applied any intervention to treat temporomandibular joint disorders or masticatory muscle disorders. The identified outcomes were categorised according to domains of the Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT). RESULTS: The electronic search resulted in 1606 studies. After removing duplicates and applying the eligibility criteria, 106 RCT were included. A total of 43 studies evaluated masticatory muscle disorders, 27 evaluated temporomandibular joint disorders, and 36 analysed mixed TMD. CONCLUSIONS: The evaluation showed significant variability in the types of outcomes and their measurement instruments. In addition, some domains such as physical and emotional functioning, participant ratings of global improvement and adverse events have been neglected when determining the effectiveness of treatments for TMD.

A survey study for the dental students' satisfaction with the "needling therapies for temporomandibular disorders" lectures.

Background/purpose: Dry needling therapy and acupuncture can effectively relieve myofascial pain in temporomandibular disorders (TMDs). This study evaluated dental students' satisfaction with the "needling therapies for TMDs" lectures given in 2022 and 2023. Materials and methods: The "needling therapies for TMDs" lectures included mainly a dry needling therapy lecture and an acupuncture lecture which were given to the fifth-year dental students in both 2022 and 2023. An additional needling therapy demonstration lecture was given in 2023 only. Immediately after the lectures, the students were asked to complete an online-based questionnaire with four survey questions regarding their satisfaction with (1) the dry needling therapy, (2) the acupuncture, (3) the overall, and (4) the needling therapy demonstration lectures using 5-point Likert scale ratings. Results: Fifty-three (80 %) of 66 and 60 (81 %) of 74 students answered the questions in 2022 and 2023, respectively. The satisfaction rates improved from 70 % in 2022 to 83 % in 2023 for the dry needling therapy lecture, from 64 % in 2022 to 85 % in 2023 for the acupuncture lecture, and from 70 % in 2022 to 88 % in 2023 for the overall lecture. The satisfaction rate was 88 % in 2023 for the needling therapy demonstration lecture. Conclusion: The results of this study suggest that inclusion of the needling therapy demonstration lecture in 2023 can results in a marked increase in the satisfaction rates for the lectures. The relatively-lower satisfaction rate for the acupuncture lecture in 2022 may be due to the difficulty in understanding the mechanisms underlying the acupuncture therapy.

Temporomandibular disorders among Ehlers-Danlos syndromes: a narrative review.

This narrative review aims to demonstrate and summarize the complex relationship between Ehlers-Danlos syndromes (EDS) and temporomandibular disorders (TMD) by reviewing the results of observational studies and case reports. EDS are a set of hereditary connective tissue disorders, where generalized joint hypermobility (GJH), especially in the hypermobile subtype (hEDS), is a key symptom. Mutations have been identified in genes that impact the production or assembly of collagen for all subtypes except hEDS. While the correlation between GJH and TMD has been analysed in various studies, fewer studies have examined TMD in patients with EDS, with most showing an increased prevalence of TMD. In case-control studies, an elevated prevalence of myalgia, arthralgia and disc-related disorders was found in individuals with EDS. Various therapeutic interventions have been reported within the literature in the form of case reports and observational studies, but there are no long-term clinical trials with results on the efficacy of different therapeutic approaches to date. This review demonstrates the high prevalence of different TMDs in different subtypes of EDS, but also shows that little is known about the success of treatment thus far. Further clinical research is necessary to provide adequate guidance on targeted treatment.

Pain symptoms are associated with two-point discrimination threshold in patients with temporomandibular disorders.

OBJECTIVE: This study aimed to explore the associations of orofacial two-point discrimination (2-PD) test result with pain symptoms and psychological factors in patients with Temporomandibular Disorders (TMDs). METHODS: 193 patients with TMDs were included in this study. Patients' demographics, pain intensity, and psychological status were recorded. The 2-PDs in the bilateral temporal, zygomatic, mandibular, and temporomandibular joint (TMJ) regions of the patients were measured. Statistical analyses were conducted to observe the associations between variables. RESULTS: For Pain-related TMDs (PT) patients, Monthly Visual Analogue Scale (VAS-M) and Current Analogue Scale (VAS-C) were correlated with TMJ, zygomatic and temporal 2-PDs. Patients with PT tended to have higher TMJ 2-PDs[Right: ß = 1.827 mm, 95%CI(0.107, 3.548), P = 0.038], zygomatic 2-PDs[Right: ß = 1.696 mm, 95%CI(0.344, 3.048), P = 0.014], temporal 2-PDs[Left: ß = 2.138 mm, 95%CI(0.127, 4.149), P = 0.037; Right: ß = 1.893 mm, 95%CI(0.011, 3.775), P = 0.049]. Associations were also observed between VAS-C and TMJ 2-PDs[Left: ß = 0.780, 95%CI(0.190, 1.370), P = 0.01; Right: ß = 0.885, 95%CI(0.406, 1.364), P = 0.001], Zygomatic 2-PDs[Right: ß = 0.555, 95%CI(0.172, 0.938), P = 0.005]; VAS-M and TMJ 2-PDs[Left: ß = 0.812, 95%CI(0.313, 1.311), P = 0.002; Right: ß = 0.567, 95%CI(0.152, 0.983), P = 0.008], zygomatic 2-PDs[Left: ß = 0.405, 95%CI(0.075, 0.735), P = 0.016; Right: ß = 0.545, 95%CI(0.221, 0.870), P = 0.001], and temporal 2-PDs [Left: ß = 0.741, 95%CI(0.258, 1.224), P = 0.003; Right: ß = 0.519, 95%CI(0.063, 0.975), P = 0.026]. CONCLUSION: TMJ, zygomatic, and temporal 2-PDs were significantly associated with PT and pain intensity. Age, gender and psychological factors were not associated with orofacial 2-PDs. PT patients exhibited weaker tactile acuity compared to Non-PT patients. Further discussion on the underlying mechanism is needed. CLINICAL RELEVANCE: Orofacial tactile acuity of TMDs patients was associated with their pain symptoms, which researchers should take account into when performing 2-PD tests for TMDs patients. The 2-PD test can be considered as a potential tool along with the current procedures for the differentiations of PT and Non-PT.

Ultrasonographic examination of masticatory muscles in patients with TMJ arthralgia and headache attributed to temporomandibular disorders.

This study used ultrasonography to compare the thickness and cross-sectional area of the masticatory muscles in patients with temporomandibular joint arthralgia and investigated the differences according to sex and the co-occurrence of headache attributed to temporomandibular disorders (HATMD). The observational study comprised 100 consecutive patients with TMJ arthralgia (71 females and 29 males; mean age, 40.01 ± 17.67 years) divided into two groups: Group 1, including 86 patients with arthralgia alone (60 females; 41.15 ± 17.65 years); and Group 2, including 14 patients with concurrent arthralgia and HATMD (11 females; 33.00 ± 16.72 years). The diagnosis of TMJ arthralgia was based on the diagnostic criteria for temporomandibular disorders. The parameters of the masticatory muscles examined by ultrasonography were subjected to statistical analysis. The pain area (2.23 ± 1.75 vs. 5.79 ± 2.39, p-value = 0.002) and visual analog scale (VAS) score (3.41 ± 1.82 vs. 5.57 ± 12.14, p-value = 0.002) were significantly higher in Group 2 than in Group 1. Muscle thickness (12.58 ± 4.24 mm) and cross-sectional area (4.46 ± 2.57 cm2) were larger in the masseter muscle than in the other three masticatory muscles (p-value < 0.001). When examining sex-based differences, the thickness and area of the masseter and lower temporalis muscles were significantly larger in males (all p-value < 0.05). The area of the masseter muscle (4.67 ± 2.69 vs. 3.18 ± 0.92, p-value = 0.004) and lower temporalis muscle (3.76 ± 0.95 vs. 3.21 ± 1.02, p-value = 0.049) was significantly smaller in Group 2 than in Group 1. An increase in VAS was significantly negatively correlated with the thickness of the masseter (r = - 0.268) and lower temporalis (r = - 0.215), and the cross-sectional area of the masseter (r = - 0.329) and lower temporalis (r = - 0.293). The masseter and lower temporalis muscles were significantly thinner in females than in males, and their volumes were smaller in patients with TMJ arthralgia and HATMD than in those with TMJ arthralgia alone. HATMD and decreased masseter and lower temporalis muscle volume were associated with increased pain intensity.

Risk factors associated with symptoms of temporomandibular disorders among women with hypermobile Ehlers-Danlos syndrome: Questionnaire-based study in Finland and Sweden.

BACKGROUND: Generalized joint hypermobility as a characteristic feature of Ehlers-Danlos syndromes (EDS) is among the factors contributing to temporomandibular disorders (TMD). OBJECTIVE: To evaluate the prevalence of TMD symptoms and their risk factors among women born in Sweden or Finland who were 27- to 78-year-olds with diagnosed hypermobile EDS (hEDS). METHODS: A cohort of women with confirmed hEDS (n = 185) was constructed from the members of the National EDS Associations in both countries. Based on questionnaire data, frequency of independent variables in terms of socio-demographic, general health and oral health-related factors, comorbid symptoms and psychological distress for self-reported TMD symptoms as the dependent variables, were calculated first. Prevalence ratios (PR) and their 95% confidence interval (95% CI) were estimated for the association between independent and dependent variables. RESULTS: Nearly all participants reported TMD symptoms (98%) with TMD pain (95%), TMJ clicking (90%) and jaw fatigue (80%) as the most common symptoms and TMJ crepitation (63%) and luxation (44%) as the least common symptoms. Risk factors for TMD among 27- to 50-year-olds participants were Finland as a country of birth, living alone and self-reported worst pain in the body (not the joints). The respective risk factors among the 51- to 78-year-olds were Finland as a country of birth, family history of EDS, tinnitus and regularly taking contraceptives. CONCLUSIONS: Among adult women with confirmed hEDS, socio-demographic and health-related factors and comorbid symptoms were significantly associated with TMD but with differences regarding age group. Therefore, management of TMD requires a multidisciplinary approach among the affected.

Visual psychosocial profiling of Chinese temporomandibular disorder pain patients and correlations with somatosensory function.

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.

Time-course of pain and salivary opiorphin release in response to oral capsaicin differ in burning mouth syndrome patients, temporomandibular disorders patients and control subjects.

OBJECTIVES: Opiorphin is an analgesic peptide released by salivary glands and capsaicin an agonist of TRPV1 receptors eliciting burning sensations. The primary objective of this study was to assess opiorphin release after stimulation of the tongue by capsaicin (STC). The secondary objectives were to compare opiorphin release after STC in 3 groups of subjects [healthy (CTRL), Burning Mouth Syndrome (BMS), painful Temporomandibular disorders (TMDp)] and pain evoked by STC in these 3 groups. MATERIALS AND METHODS: Salivary opiorphin was assessed with high-performance liquid chromatography at 3 different time points (baseline, after 5 min and 20 min of STC). Pain was self-reported on a (0-10) numeric rating scale. RESULTS: Three groups (N = 16) of adults were recruited at the Clinical Hospital Centre and School of Dental Medicine in Zagreb. Opiorphin levels were higher (1) in TMDp compared to CTRL in 1st (2.23 ± 1.72 pg/ul vs. 0.67 ± 0.44 pg/ul, p = 0.002) and 3rd sampling (2.44 ± 2.01 pg/ul vs. 0.74 ± 0.52 pg/ul, p = 0.020) and (2) within BMS group at 3rd sampling vs. baseline (p < 0.025). Pain scores were higher in BMS compared to TMDp (p < 0.025) and CTRL (p < 0.025). CONCLUSION: This study evidenced (1) a differential basal amount of opiorphin in two pain conditions and control subjects (2) a differential kinetic of release of opiorphin after STC in CTRL, BMS and TMDp (3) a differential pain perception after STC in BMS and TMDp vs. CTRL, which can provide a readout for animal models. CLINICAL RELEVANCE: The specific regulation of opiorphin release in patients with orofacial painful conditions provides valuable insights for clinicians and researchers in physiology and pathology and encourages further research in this area. TRIAL REGISTRATION: ClinicalTrials.gov NCT04694274. Registered on 01/05/2021.

Microstructural, Micromechanical Atlas of the Temporomandibular Joint Disc.

The temporomandibular joint (TMJ) disc is mainly composed of collagen, with its arrangement responding to efficient stress distribution. However, microstructural and micromechanical transformations of the TMJ disc under resting, functional, and pathological conditions remain unclear. To address this, our study presents a high-resolution microstructural and mechanical atlas of the porcine TMJ disc. First, the naive microstructure and mechanical properties were investigated in porcine TMJ discs (resting and functional conditions). Subsequently, the perforation and tear models (pathological conditions) were compared. Following this, a rabbit model of anterior disc displacement (abnormal stress) was studied. Results show diverse microstructures and mechanical properties at the nanometer to micrometer scale. In the functional state, gradual unfolding of the crimping cycle in secondary and tertiary structures leads to D-cycle prolongation in the primary structure, causing tissue failure. Pathological conditions lead to stress concentration near the injury site due to collagen interfibrillar traffic patterns, resulting in earlier damage manifestation. Additionally, the abnormal stress model shows collagen damage initiating at the primary structure and extending to the superstructure over time. These findings highlight collagen's various roles in different pathophysiological states. Our study offers valuable insights into TMJ disc function and dysfunction, aiding the development of diagnostic and therapeutic strategies for TMJ disorders, as well as providing guidance for the design of structural biomimetic materials.

Effect of the application of digital technology-assisted optimization in the process of adjusting jaw position.

OBJECTIVES: The aim of this study was to demonstrate a novel jaw position adjustment technique derived from digital twins and evaluate the application effect of digital technology-assisted optimization in the process of adjusting jaw position on patients with temporomandibular disorders (TMD). METHODS: A total of 74 patients with TMD who attended the Department of Temporomandibular Joint, West China Hospital of Stomatology, Si-chuan University, between June 2022 and May 2023 were selected. The patient's initial computed tomography (CT) and bilateral temporomandibular joint data obtained by magnetic resonance imaging (MRI) were collected. The 148 joints were divided into the normal disc-condyle relationship (N) group, disc displacement with reduction (DDWR) group, and disc displacement without reduction (DDWoR) group. Assisted by digital technology, the patient's CT data were reconstructed, and a personalized reference plane was established to adjust the jaw position. A three-point bite guiding splint was designed by the adjusted occlusal space and then fabricated by 3D printing technology. It was worn by the patients and then reviewed by MRI. Before and after the adjustment of jaw position, the amount and direction of condyle and disc displacement and the angle between condyle and disc were measured as the evaluation indexes of the effect of the adjustment. The correlation with condylar displacement was evaluated. RESULTS: In the N group, the disc moved backward and downward along the X and Z axes by (-0.60±0.62) and (0.51±0.71) mm, respectively. In the DDWR group, the disc moved backward and upward along the X and Z axes by (-1.33±1.38) and (-0.09±1.31) mm, respectively. In the DDWoR group, the disc moved forward and downward along the X and Z axes by (0.49±1.76) and (1.35±1.76) mm, respectively. The angle between the condyle and the disc decreased after adjustment of the jaw position in all three groups. All patients showed improvement in symptoms after adjustment. CONCLUSIONS: Digital technology-assisted jaw position adjustment can simplify the process, reduce the sensitivity of the technique, and improve patients' disc-condyle structure and symptoms. Therefore, its application in the treatment of patients with TMD is of great clinical significance.

A Meta-Analysis of the Global Prevalence of Temporomandibular Disorders.

Background: This meta-analysis aims to evaluate the proportion of people with TMDs in different studies, considering factors such as geographical region, patient age, and sample size. Methods: The search yielded 6984 articles on the incidence of TMDs. Finally, 74 studies with 172,239 subjects and 35,259 with TMDs were selected for final analysis. Analyses were performed using the R statistical language. Results: The incidence of TMDs in the world population was 34%. The age group 18-60 years is the most exposed to TMDs. From the data presented, we observed that for each continent, the female group was 9% to 56% larger than the male group. The highest female-to-male ratio (F:M) was reported in South America (1.56), whereas the lowest F:M ratio was reported in Europe (1.09), suggesting an almost equal distribution of males and females. Conclusions: This suggests that geographical location may play a role in the results of the studies. The prevalence of TMDs was significantly higher in South America (47%) compared to Asia (33%) and Europe (29%). Larger epidemiological studies of TMDs in African and Australian populations are recommended. In conclusion, both visual and statistical assessments suggest that the results of our meta-analysis are robust and unlikely to be significantly affected by publication bias. This suggests that geographical location may play a role in the prevalence of TMDs.

Temporomandibular disorders in individuals with Marfan syndrome: an exploratory analysis.

BACKGROUND: This study aims to analyze to what extent patients with Marfan syndrome (MFS) are affected by temporomandibular disorders (TMD) and its impact on oral health-related quality of life (OHRQoL). To collect data, an online questionnaire was created to recruit participants from Germany, Austria, and Switzerland through social media and support groups. The questionnaire consists of free-text questions, the German versions of the Oral Health Impact Profile (OHIP-G14), the Depression Anxiety Stress Scale (DASS), and the Graded Chronic Pain Status (GCPS). RESULTS: A total of 76 participants with diagnosed MFS were included. Of these, 65.8% showed TMD symptoms, the most common being pain or stiffness of the masticatory muscles in the jaw angle (50.0%). Only 14.5% of the participants were already diagnosed with TMD. Of the participants with an increased likelihood of a depression disorder, 76.9% showed TMD symptoms. Of those with a critical score for an anxiety disorder, 90.9% showed TMD symptoms. 73.3% of participants with TMD symptoms reached the critical score for a stress disorder. TMD symptoms were associated with a higher risk for chronic pain. In the median, participants with TMD showed statistically notably higher OHIP-G14 scores than participants without TMD (11.5 [IQR 17] vs. 1 [IQR 3] points, p ≤ 0.001). CONCLUSION: TMD symptoms had a noticeable impact on OHRQoL in patients with MFS, i.e., chronic pain and psychological impairment. TMD seems underdiagnosed, and more research is needed to prevent the associated chronification of pain and psychological burden to improve the OHRQoL.