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.

Impact of the COVID-19 pandemic on clinical and psychological aspects of temporomandibular disorders.

BACKGROUND: The Coronavirus 2019 disease (COVID-19) caused drastic changes in people's lifestyle that affected TMD characteristics through its physical and psychological influences. The aim of this study was to define the clinical and psychological characteristics of a large group of well-defined TMD patients and seek their differences between before and during the COVID-19 pandemic to establish points of care to be emphasized in the post-pandemic era. METHODS: TMD patients diagnosed by the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) aged ≥ 18 were analyzed. Samples between September, 2017 to July, 2019 (n = 455) and March, 2021 to June, 2022 (n = 338) were collected to represent before and during COVID-19, respectively. The Graded Chronic Pain Scale (GCPS) and Symptom Checklist-90-Revision (SCL-90-R) were used to evaluate disability levels and psychological status. Clinical indices were compared between COVID periods and factors related to higher pain levels were investigated according to pandemic period. RESULTS: More patients reported pain on palpation of the masticatory muscles during the pandemic (p = 0.021) while the number decreased for neck muscles (p = 0.001) and TMJ (p < 0.001) areas. Patients reporting nocturnal bruxism (23.3-29.6%) and clenching (45.1-54.7%) significantly increased during the pandemic. TMD patients with pain without disability were more common during the pandemic regardless of pain intensity (p < 0.001). The number of patients expressing interference in daily activities decreased drastically during COVID-19 regardless of disability level (p < 0.001). Factors associated with higher than moderate pain intensity (CPI ≥ 50) were insomnia (odds ratio [OR] = 1.603, p = 0.047) and somatization (OR = 1.082, p < 0.001) before the pandemic. During the pandemic, age (OR = 1.024, p = 0.007), somatization (OR = 1.070, p = 0.006), and paranoid ideation (OR = 1.117, p = 0.003) were significantly associated with higher pain intensity. CONCLUSIONS: The results of our study underline the importance of evaluating psychological profiles of TMD patients, especially somatization, paranoid ideation and psychoticism, in exceptional situations that may cause a change in individual mental status. This will lead to a better understanding of the individual TMD patient and help in planning personalized treatment strategies that will assist the patient in adjusting to changes occurring in special environments such as the COVID-19 pandemic.

Occurrence of Cervical Spine Pain and Its Intensity in Young People with Temporomandibular Disorders.

Background: The main aim of this cross-sectional study was to compare the occurrence and severity of cervical spine pain in young adults diagnosed with TMDs with a healthy control group (without TMDs). Methods: The study was conducted from June to July 2023. Inclusion criteria were age (18-30 years), cervical spine pain (for at least 1 month), and consent to participate in the study. The study was conducted based on RDC/TMD protocol, an original questionnaire, and a physiotherapeutic examination focused on detecting TMDs. The cervical pain level was assessed using the Visual Analogue Scale (VAS). Thus, a total of 95 subjects were registered for the trials, 51 people (53.7%) constituted the control group (without TMDs), while 44 (46.3%) people constituted the study group (with TMDs). Results: The mean age of people participating in the study was 22.2 ± 2.2 years in the study group and 22.5 ± 3.1 years in the control group. The largest group was people aged 21-25 (n = 51 people, 53.7%). Patients from the study group more often experienced pain in the stomatognathic system during palpation (both in the muscle, joint, and musculoskeletal groups) and had reduced mobility of the temporomandibular joints in every movement (p < 0.001). People from the study group were also characterized by less mobility of the cervical spine (p < 0.05), apart from extension movement (p > 0.05). The analysis showed that of the 95 people participating in the study, 85.4% reported problems in the cervical spine area (n = 81), of which almost all people in the study group struggled with this problem (n = 43, 97.7%). It was found that cervical spine pain was significantly more common in people with TMDs (p < 0.05, chi2 = 10.118, df = 1, rc = 0.31). The level of pain was significantly higher in people from the study group (p < 0.001, chi2 = 45.765, df = 4, rc = 0.57). Conclusions: Our research has shown that the occurrence of cervical spine pain is more common in the group of young people with temporomandibular disorders (TMDs). In young people, this problem is rarely recognized and properly treated.

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.

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.

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.

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.

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.

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.

Impact of professional, recreational and nonsinging on temporomandibular disorders - a comparative study based on a self-assessment questionnaire.

BACKGROUND: This study investigates the relationship between professional and recreational singing on temporomandibular disorders (TMDs) in women compared to a nonsinging control group. METHODS: A total of 288 female subjects between the ages of 18 and 45 participated in the self-assessment questionnaire including demographic data, as well as questions on vocal practice and TMDs symptoms. Depending on the singing time per week, the (non)vocalists were assigned to the groups professional (n = 96), recreational (n = 96) and nonsingers (n = 96). RESULTS: The TMDs prevalence in professional singers (42%) was higher than that in recreational singers (31%) and noticeably higher than that in nonsingers (25%). The Fisher-Freeman-Halton exact test showed that the differences between the groups were not noticeable (p = .053) but could be formulated as tendencies. The professionals suffered much more from restricted jaw movement (p = .004; OR = 2.718; 95% CI = 1.409-5.242), temporomandibular joint sounds (p < .009; OR = 2.267; 95% CI = 1.264-4.064) and temporomandibular pain (p = .010; OR = 2.333; 95% CI = 1.264-4.308) than nonsingers. CONCLUSIONS: Singing might have an enhancing effect on the appearance of TMDs. In particular, professional singers suffered more from self-reported TMDs than recreational singers and nonsingers. In addition to the high level of physical workload if participating in professional singing, the psychosocial impact should be investigated more in further studies. No new treatment strategies resulted from this study, as the etiological significance of singing is still unclear. Knowledge about risk factors for multifactorial TMDs can help practitioners and patients prevent and treat TMDs.

Elevated pain sensitivity is associated with reduced REM sleep in females with comorbid temporomandibular disorder and insomnia.

OBJECTIVE: Patients with chronic pain disorders, including Temporomandibular Disorders (TMDs) endorse high levels of sleep disturbances, frequently reporting reduced sleep quality. Despite this, little is known about the effect that daytime pain has on the microstructure and macro-architecture of sleep. Therefore, we aimed to examine the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST), is associated with objective sleep parameters the following night, including sleep architecture and power spectral density, in women with TMD. METHODS: : 144 females with myalgia and arthralgia by examination using the Diagnostic criteria for TMD completed a comprehensive QST battery consisting of General Pain Sensitivity, Central Sensitization Index, and Masseter Pressure Pain Threshold assessments. Polysomnography (PSG) was collected the same night to measure sleep architecture and calculate relative power in delta, theta, alpha, sigma, and beta power bands. RESULTS: Central Sensitization (B= -3.069, P = 0.009), General Pain Sensitivity Indices (B= -3.069, P = 0.007), and Masseter Pain Pressure Threshold (B = 0.030, P = 0.008) were significantly associated with lower REM% both before and after controlling for covariates. Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands, nor with any other sleep architectural stages. CONCLUSIONS: Our findings demonstrate that higher generalized pain sensitivity, masseter pain pressure threshold, as well as central sensitization were associated with a lower percentage of REM in participants with myofascial pain and arthralgia of the masticatory system. These findings provide an important step toward understanding the mechanistic underpinnings of how chronic pain interacts with sleep physiology.

Biomechanical study of temporomandibular joints of patients with temporomandibular disorders under incisal clenching: A finite element analysis.

Temporomandibular disorders (TMD) encompass a collection of pathologies. Within the multitude of etiological factors contributing to TMD, mechanical factors hold significant importance. The aim of this investigation was to assess the magnitude and distribution of stresses encountered by the temporomandibular joints (TMJs) during incisal clenching among TMD patients while also elucidating the mechanical pathogenesis underlying TMD. Ten asymptomatic subjects and ten TMD patients were recruited. The Control, Bilateral, and Unilateral groups were set. The contact stress, maximum principal stress, and minimum principal stresses of TMJ structures among the groups were compared. In addition, comparisons of the contact stress distribution among the groups were adopted. In the Control and Bilateral groups, the magnitudes of stresses (contact stress, maximum and minimum principal stresses) between the right and left sides showed no significant difference (P > 0.05). For unilateral TMD patients,the minimum principal stress on the condyle in the Uni-N group (the normal side) was significantly greater than thatin the Uni-T group (the TMD side)(P = 0.016, mean difference 9.99 MPa [95 %CI: 3.11 to 16.87]). Furthermore, stresses on the condyle and fossa of the patients were significantly greater than those of asymptomatic subjects (P < 0.05). The contact stress distributions were concentrated in the Control group while irregular in the TMD groups. In conclusion, asymmetrical contact stress distributions were observed in unilateral TMD, with excessive stresses on the healthy side. The protection of the healthy TMJ during treatment is recommended for patients with unilateral TMD.

Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review.

Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.

The relationship between pregnancy and temporomandibular disorder (TMD) through diagnostic criteria for temporomandibular disorders (DC/TMD) axis II evaluation: a case-control cross-sectional study.

INTRODUCTION: This study focuses on temporomandibular disorders (TMDs), which affect the temporomandibular joint and related muscles and have multiple causes. Recent studies have examined the connection between menstrual cycles, estrogen levels, and TMDs, but results are inconsistent, highlighting the need for more research. The aim is to explore the prevalence of TMDs in pregnant women and consider how hormonal changes during pregnancy might influence these disorders. METHODS: In this cross-sectional case-control study, we compared 32 pregnant women with 35 non-pregnant women. We evaluated several TMD-related factors such as pain levels, chronic pain classification, scores on the Jaw Functional Limitation Scale-20 and Oral Behaviors Checklist, and psychological health. We used various statistical methods including descriptive statistics, chi-square tests, linear regression, and adjustments for multiple comparisons to analyze the data. RESULTS: Pregnant women showed different pain perceptions, generally reporting less pain and lower severity. Nonetheless, these differences were not uniform across all TMD-related measures. Linear regression did not find a consistent link between pregnancy and TMD scores, except for chronic pain grade, which was not significant after adjusting for multiple comparisons. There was a significant relationship between depression and TMD severity, emphasizing the need to consider mental health in TMD evaluations. DISCUSSION: The findings suggest that pregnancy is neither a risk nor a protective factor for TMD. Differences in pain perception, functional status, and psychological health were observed in pregnant women but were not consistent for all TMD-related aspects. The role of estrogen in TMJ health and TMD risk is complex and requires further study. The research highlights the necessity of including mental health, especially depression, in TMD assessments. More comprehensive research with larger sample sizes is essential to better understand the connections between pregnancy, TMD, and hormones, aiming to improve TMD management in pregnant women and others.

The effect of different pain characteristics on jaw functional limitations in patients with temporomandibular disorders.

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

Etiologic Factors of Temporomandibular Disorders: A Systematic Review of Literature Containing Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) from 2018 to 2022.

This study aims to conduct a systematic analysis of literature published between 1 January 2018 and 1 September 2022, exploring factors influencing the progression or development of temporomandibular disorders (TMD), diagnosed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) or Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Three electronic databases were reviewed to identify papers that examined TMD factors using DC/TMD or RDC/TMD. Inclusion criteria encompassed original research published in English between 1 January 2018 and 1 October 2022, online, and complete DC/TMD or RDC/TMD studies on human participants aged 18 or older. Two authors independently assessed the risk of bias using The Joanna Briggs Institute (JBI) Analytical cross-sectional studies' Critical Appraisal Tool. Of 1478 articles, 11 were included. The studies revealed strong associations between TMD and factors such as female, poor sleep quality, depression, oral parafunction, anxiety, somatization, and anatomical features. However, variables such as education, living conditions, socioeconomic status, marital status, chronic pain, and stress did not exhibit statistically significant correlations. Based on the obtained data, it can be concluded that the causes of TMD are largely related to psychological factors, which supports the biopsychosocial theory of the disorder.

Association between stress and catecholamines with painful TMD in children.

BACKGROUND: Studying biomarkers in children with temporomandibular disorders (TMD) such as epinephrine, norepinephrine, and dopamine may reveal factors like screen time or sleep loss that affect these biomarkers and predict TMD-related pain, offering new research opportunities. AIM: To determine the association between stress and catecholamines with myofascial pain and headache related to TMD in children. DESIGN: Sixty-six 9- to 11-year-old children assisting at the clinics of Pediatric Dentistry of Universidad CES participated in the study. Myofascial pain and headache attributed to TMD were determined according to the Diagnostic Criteria for TMD (DC/TMD) Axis I. Stress was evaluated with the Perceived Stress Scale-Children (PSS-C), and a 24-h urine sample was analyzed using liquid chromatography to assay catecholamines. Single and multiple regression analyses were performed. RESULTS: Children with a mean age of 10.3 years participated in the study. The mean score of stress was 29 ± 4. Perceived stress, dopamine, epinephrine, and norepinephrine were statistically significant predictors of myofascial pain and headache attributed to TMD in the single- and multiple variable logistic regression analyses. CONCLUSION: Stressful states and its biological biomarkers increase the probability of developing myofascial pain and headache attributed to TMD in children.

The biomechanical effects of bimaxillary osteotomies to the patients with mandibular retraction under incisal clenching.

The purpose of this study is to investigate the biomechanical effect of bimaxillary osteotomies on patients with mandibular retraction. Mandibular retraction, as a typical maxillofacial deformity, and has great adverse effects on TMJ. Bimaxillary osteotomies are widely used to correct symptoms of mandibular retraction. It is necessary to understand the effect of surgery on temporomandibular disc (TMJ). Five patients with mandibular retraction and 10 asymptomatic subjects were involved in this study. Finite element models of preoperative, postoperative and control group were constructed based on the CT data. Nine sets of concentrated forces were used to simulate the muscle effect and contact method was used to simulate the interaction within the TMJs and dentitions. The results showed that bimaxillary osteotomies could effectively improve the maxillofacial morphology and alleviate the overload in TMJ. The facial asymmetry and right chewing side preference could cause imbalanced stress distributions in the TMJs and interfere the surgical treatment.