Identifying phenotypes in persons with temporomandibular disorders, using latent class analyses: Temporomandibular disorders and phenotypes.

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

A case of Melkersson-Rosenthal syndrome with temporomandibular joint osteoarthritis: multidisciplinary treatment and autoimmune etiological hypothesis.

BACKGROUND: Melkersson-Rosenthal syndrome (MRS) is a rare neuro-mucocutaneous disorder characterized by recurrent edema, facial palsies, and nerve dysfunctions often associated with the plicata tongue. Although the etiology of MRS is not well understood, there is growing evidence suggesting an autoimmune involvement. CASE PRESENTATION: This paper presents a case report of a 25-year-old male with MRS as the initial symptom, followed by temporomandibular joint osteoarthritis (TMJ-OA). A comprehensive diagnosis and multidisciplinary treatment approach including surgery, local injections, and oral medication were implemented, resulting in a favorable prognosis. CONCLUSIONS: These findings support the hypothesis that MRS is a systemic granulomatous disease caused by autoimmunity, which may also influence the occurrence and development of TMJ-OA through immune-related mechanisms. This study emphasizes the significance of systemic immune regulation in the treatment of patients with MRS and TMJ-OA comorbid conditions.

Motion reconstruction and finite element analysis of the temporomandibular joint during swallowing in healthy adults.

There is a close physiological connection between swallowing and the temporomandibular joint (TMJ). However, a shortage of quantitative research on the biomechanical behavior of the TMJ during swallowing exists. The purpose of this study was to reconstruct the movement of the temporomandibular joint (TMJ) based on in vivo experiment and analyze the biomechanical responses during swallowing in healthy adults to investigate the role of the TMJ in swallowing. Motion capture of swallowing, computed tomography (CT), and magnet resonance images (MRI) were performed on six healthy subjects. The movements of the TMJ during swallowing were reconstructed from the motion capture data. The three-dimensional finite element model was constructed. The dynamic finite element analysis of the swallowing process was performed based on the motion data. The range of condylar displacement was within 1 mm in all subjects. The left and right condyle movements were asymmetrical in two-thirds of the subjects. The peak stresses of the discs were relatively low, with a maximum of 0.11 MPa. During swallowing, the condylar displacement showed two trends: slow retraction and slow extension. The tendency to extend could lead to a gradual increase in stress on the disc.

Multi-class segmentation of temporomandibular joint using ensemble deep learning.

Temporomandibular joint disorders are prevalent causes of orofacial discomfort. Diagnosis predominantly relies on assessing the configuration and positions of temporomandibular joint components in magnetic resonance images. The complex anatomy of the temporomandibular joint, coupled with the variability in magnetic resonance image quality, often hinders an accurate diagnosis. To surmount this challenge, we developed deep learning models tailored to the automatic segmentation of temporomandibular joint components, including the temporal bone, disc, and condyle. These models underwent rigorous training and validation utilizing a dataset of 3693 magnetic resonance images from 542 patients. Upon evaluation, our ensemble model, which combines five individual models, yielded average Dice similarity coefficients of 0.867, 0.733, 0.904, and 0.952 for the temporal bone, disc, condyle, and background class during internal testing. In the external validation, the average Dice similarity coefficients values for the temporal bone, disc, condyle, and background were 0.720, 0.604, 0.800, and 0.869, respectively. When applied in a clinical setting, these artificial intelligence-augmented tools enhanced the diagnostic accuracy of physicians, especially when discerning between temporomandibular joint anterior disc displacement and osteoarthritis. In essence, automated temporomandibular joint segmentation by our deep learning approach, stands as a promising aid in refining temporomandibular joint disorders diagnosis and treatment strategies.

Intra-articular and intraosseous approach to temporomandibular joint-targeted injections: a cadaveric investigation.

PURPOSE: Temporomandibular joint osteoarthritis (TMJ-OA) management is complex, and several conservative and minimally invasive protocols have been proposed. Intra-articular injections of medications directed at OA have been performed, but in some cases, these medications do not directly contact the tissue lesion sites. Here, we propose a new real-time ultrasound-guided technique to inject medications directly into the subchondral bone. METHODS: Ultrasound image screening was carried out with the point-of-care Clarius L15 device. Then, with the patient's mouth closed, a stainless-steel cannula with a concentric trocar was US-guided using an in-plane approach until the perforating tip of the internal trocar touched the lateral pole of the mandibular condyle. Then, the trocar was inserted through the medullary bone, where a posterior injection was made. RESULTS: The technique's precision was confirmed by capturing an iodine contrast solution that imaged the medullary condyle of fresh anatomical specimens processed by computed tomography. CONCLUSION: The proposed technique was effective in accessing the mandibular condyle subchondral bone in the inferior TMJ space for the simultaneously intra-articular (IA) and intra-osseous (IO) in-plane US-guided injections. Thus, its implementation may represent an important advance in early TMJ-OA treatment. This may be a promising approach, especially in OA cases in which the cortical bone is still preserved.

Automatic detection and visualization of temporomandibular joint effusion with deep neural network.

This study investigated the usefulness of deep learning-based automatic detection of temporomandibular joint (TMJ) effusion using magnetic resonance imaging (MRI) in patients with temporomandibular disorder and whether the diagnostic accuracy of the model improved when patients' clinical information was provided in addition to MRI images. The sagittal MR images of 2948 TMJs were collected from 1017 women and 457 men (mean age 37.19 ± 18.64 years). The TMJ effusion diagnostic performances of three convolutional neural networks (scratch, fine-tuning, and freeze schemes) were compared with those of human experts based on areas under the curve (AUCs) and diagnosis accuracies. The fine-tuning model with proton density (PD) images showed acceptable prediction performance (AUC = 0.7895), and the from-scratch (0.6193) and freeze (0.6149) models showed lower performances (p < 0.05). The fine-tuning model had excellent specificity compared to the human experts (87.25% vs. 58.17%). However, the human experts were superior in sensitivity (80.00% vs. 57.43%) (all p < 0.001). In gradient-weighted class activation mapping (Grad-CAM) visualizations, the fine-tuning scheme focused more on effusion than on other structures of the TMJ, and the sparsity was higher than that of the from-scratch scheme (82.40% vs. 49.83%, p < 0.05). The Grad-CAM visualizations agreed with the model learned through important features in the TMJ area, particularly around the articular disc. Two fine-tuning models on PD and T2-weighted images showed that the diagnostic performance did not improve compared with using PD alone (p < 0.05). Diverse AUCs were observed across each group when the patients were divided according to age (0.7083-0.8375) and sex (male:0.7576, female:0.7083). The prediction accuracy of the ensemble model was higher than that of the human experts when all the data were used (74.21% vs. 67.71%, p < 0.05). A deep neural network (DNN) was developed to process multimodal data, including MRI and patient clinical data. Analysis of four age groups with the DNN model showed that the 41-60 age group had the best performance (AUC = 0.8258). The fine-tuning model and DNN were optimal for judging TMJ effusion and may be used to prevent true negative cases and aid in human diagnostic performance. Assistive automated diagnostic methods have the potential to increase clinicians' diagnostic accuracy.

Which of the autologous blood products administered simultaneously with arthrocentesis is more effective in terms of clinical outcomes?

This study aimed to determine which of the autologous blood products administered simultaneously with arthrocentesis is more effective on clinical outcomes in patients with temporomandibular joint disorder. The study included 116 patients who underwent arthrocentesis alone, i-PRF (injectable- Platelet Rich Fibrin) with arthrocentesis, and PRP (Platelet Rich Plasma) with arthrocentesis. A total of 35 patients underwent arthrocentesis (Group A), 47 patients underwent arthrocentesis with i-PRF (Group APRF) and 34 patients underwent arthrocentesis with PRP (Group APRP). All patients received local anaesthesia before the procedure, and then the upper joint cavity was irrigated with approximately 100 mL of saline solution. Subsequently, patients in Group APRF and Group APRP were administered 2 ml of autologous blood product. All patients' pain and maximum mouth opening values were compared statistically at each time point: before the procedure, 1 week, 1 month, 3 months, and 6 months after the procedure. The results demonstrated no significant difference among the groups in terms of pain. Nevertheless, in terms of maximum mouth opening, superior outcomes were observed in the early postoperative period in the PRP group, while superior outcomes were observed in the late postoperative period in the i-PRF group.

Comparing microstructural and micromechanical deformation of the TMJ disc in two anterior disc displacement models.

OBJECTIVE: Anterior disc displacement (ADD) has been used to establish temporomandibular joint disorder (TMD) models. Based on whether preserve of the retrodiscal attachment, the modelling methodologies include ADD with dissecting the retrodiscal attachment (ADDwd) and ADD without dissecting the retrodiscal attachment (ADDwod). This article aims to determine which model better matches the micromechanical and microstructural progression of TMD. METHODS: Through meticulous microscopic observations, the microstructure and micromechanical deformation of the TMJ discs in ADDwd and ADDwod rabbit models were compared at 2 and 20 weeks. RESULT: Scanning electron microscopy and transmission electron microscopy showed that collagen fibres became slenderized and straightened, collagen fibrils lost diameter and arrangement in the ADDwd group at 2 weeks. Meanwhile, nanoindentation and atomic electron microscopy showed that the micro- and nano- mechanical properties decreased dramatically. However, the ADDwod group exhibited no significant microstructure and micromechanical deformations at 2 weeks. Dissection of the retrodiscal attachment contribute in the acceleration of disease progression at the early stage, the devastating discal phenotype remained fundamentally the same within the two models at 20 weeks. CONCLUSION: ADDwod models, induced stable and persistent disc deformation, therefore, can better match the progression of TMD. While ADDwd models can be considered for experiments which aim to obtain advanced phenotype in a short time.

Structural MRI findings in the brain related to pain distribution in chronic overlapping pain conditions: An explorative case-control study in females with fibromyalgia, temporomandibular disorder-related chronic pain and pain-free controls.

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

Temporomandibular Joint Disorders and Pain Confounders: An Awareness Study.

OBJECTIVES: Temporomandibular disorders (TMD) are the most common nonodontogenic cause of orofacial pain, leading to morbidity and impairment. TMD presents a diagnostic challenge due to many aetiologies that exhibit comparable symptoms and refer pain to the temporomandibular joint (TMJ) region. Patients may be referred to dental specialists without accounting for all pain sources. This study aims to identify radiographic confounders (RCs) that can be mistaken for TMD in patients undergoing TMJ assessment using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A review of 369 CBCT oral maxillofacial radiology reports of the TMJ acquired between July 2020 and June 2023 was completed. Pertinent RCs were classified as endodontic lesions, impacted dentition, sinus pathologies, root fractures, soft tissue calcifications, and others. The chi-squared test assessed the significance of the relationship between RCs and patient variables. RESULTS: A total of 283 RCs were identified in 202 of the 369 cases (54.7%). The most frequent findings included sinus abnormalities (32.5%), endodontic lesions (15.2%), impacted dentition (12.7%), and elongated/calcified stylohyoid process (9.2%). Significant associations were found between sinus pathologies with TMD signs (P = .009) and gender (P = .001). CONCLUSION: Our results indicate that RCs that mimic TMD-related symptoms are prevalent in patients referred for TMJ CBCT imaging. CLINICAL RELEVANCE: Clinicians should be aware of these RCs when diagnosing complaints related to the TMJ. We recommend clinicians first obtain dental clearance and investigate all other potential sources of a patient's complaint before initiating referrals to avoid unnecessary costs and delays in patient care.

Synovial microenvironment in temporomandibular joint osteoarthritis: crosstalk with chondrocytes and potential therapeutic targets.

Temporomandibular joint osteoarthritis (TMJOA) is considered to be a low-grade inflammatory disease involving multiple joint tissues. The crosstalk between synovium and cartilage plays an important role in TMJOA. Synovial cells are a group of heterogeneous cells and synovial microenvironment is mainly composed of synovial fibroblasts (SF) and synovial macrophages. In TMJOA, SF and synovial macrophages release a large number of inflammatory cytokines and extracellular vesicles and promote cartilage destruction. Cartilage wear particles stimulate SF proliferation and macrophages activation and exacerbate synovitis. In TMJOA, chondrocytes and synovial cells exhibit increased glycolytic activity and lactate secretion, leading to impaired chondrocyte matrix synthesis. Additionally, the synovium contains mesenchymal stem cells, which are the seed cells for cartilage repair in TMJOA. Co-culture of chondrocytes and synovial mesenchymal stem cells enhances the chondrogenic differentiation of stem cells. This review discusses the pathological changes of synovium in TMJOA, the means of crosstalk between synovium and cartilage, and their influence on each other. Based on the crosstalk between synovium and cartilage in TMJOA, we illustrate the treatment strategies for improving synovial microenvironment, including reducing cell adhesion, utilizing extracellular vesicles to deliver biomolecules, regulating cellular metabolism and targeting inflammatory cytokines.

Surgical management of a temporal meningoencephalocele with a patient-specific combined craniofossa prosthesis: illustrative case.

BACKGROUND: Meningoencephaloceles can originate through any defect in the cranial bones, including the skull base. They can be completely asymptomatic or present with typical symptoms such as headaches, seizures, or meningitis. OBSERVATIONS: The authors present the case of a 54-year-old female who presented with right-sided ear and temporomandibular joint (TMJ) pain. Computed tomography showed a large lytic lesion of the squamous part of the temporal bone with cortical bone destruction, extending to the mandibular fossa. Magnetic resonance imaging demonstrated a temporal bone meningoencephalocele. The patient underwent resection, dural repair, and multilayer reconstruction with a patient-specific three-dimensional-printed titanium combined craniofossa prosthesis. LESSONS: To the authors' knowledge, this is the first case report of TMJ pain associated with a temporal meningoencephalocele. The exact location and extension of the lesion determine the surgical approach and need for reconstruction in temporal bone meningoencephaloceles. In cases of destruction of the mandibular fossa, a patient-specific combined craniofossa prosthesis is recommended to reconstruct the bone defect. https://thejns.org/doi/10.3171/CASE24132.

Role of Low-Level Laser Therapy in the Management of Temporomandibular Joint Arthralgia.

To study the efficacy of low-level laser therapy in the management of temporomandibular joint arthralgia. Design Interventional study (pre-post study), Setting Meenakshi Medical College And Hospital, Research Institute. Subjects 50 patients with temporomandibular joint arthralgia were evaluated for pain, mouth opening and clicking sound while mouth opening before and after treatment. Method Patients are subjected to undergo low-level laser therapy with Infrared and red rays with a therapeutic dosage ranging from 8 J/cm2 to 15 J/cm2 up to 3-5 sessions for a month each session lasts for 15-20 min. The patients are to be followed up regularly after 1, 3, 6 and 8 months in the study.The study measured the range of mouth opening in patients before and after undergoing low-level laser therapy. Before treatment, the range of mouth opening was from 2.78 to 3.97 cm, with a mean value of 2.78 cm and a standard deviation of 0.22. After treatment, the range of mouth opening was from 2.78 to 3.97 cm, with a mean value of 3.97 cm and a standard deviation of 0.24. The study also measured the VAS score for pain, with a mean and standard deviation of 7.9 ± 0.73 before treatment and 0.88 ± 0.718 after treatment. There was a significant difference between the pretreatment and post-treatment VAS scores, with a P-value of 0.05. Low-level laser therapy is an effective non invasive treatment modality for temporomandibular joint arthralgia. The patients who underwent this procedure had symptomatic relief and no remissions were observed.

Temporomandibular joint disc responses to installation and removal of the experimental malocclusion.

BACKGROUND: Aberrant occlusion and aging are two main risks for temporomandibular joint (TMJ) degeneration. OBJECTIVE: To assess the combined impact of occlusion and age on TMJ disc. METHODS: To avoid the confounding impact of gender, presently, 126 female C57BL/6J mice, 63 youngsters, 6-week old and 63 adults, 28-week old, were used. An experimental bilateral anterior crossbite (BAC) relation was created by installing metal tubes onto the mandibular incisors. Mice were sacrificed at 3, 7 and 11 weeks (n = 9). Additionally, the installed tubes were removed at 7 weeks in removal groups and the TMJs were sampled after another 4 weeks (n = 9). Disc changes were detected by histomorphology, immunohistochemistry, and western blot assays. RESULTS: Disc deformation was obvious in BAC groups. The typical change was hyperplasia at the posterior region of the disc where there was significant infiltration of inflammatory cells. Expressions of the inflammatory markers, including tumour necrosis factor-α and interleukin-1ß, and the catabolic markers, including fibronectin (FN), FN N-terminal fragments, and vascular endothelial growth factor-A, were all increased. The changes were more obvious in adults than in youngsters. Removal of BAC attenuated inflammatory and catabolic changes in the youngsters, but the inflammatory markers recovered little in the adults. CONCLUSION: TMJ disc responds to BAC by degeneration and inflammation, and respond to BAC removal by rehabilitation. Adult discs show severer degeneration responses to BAC and a lower level of anti-inflammatory capability to BAC removal than the youngster's discs. Animals cannot be equated with humans. The human disc response to occlusion changes worth further exploration.

The influence of open disc repositioning surgery on the internal derangement of the contralateral temporomandibular joint: a prospective study of 96 patients.

OBJECTIVE: To assess the influence of unilateral open disc repositioning surgery (ODRS) of the temporomandibular joint (TMJ) on the internal derangement (ID) of the contralateral joint. METHODS: Patients with bilateral ID of TMJ who underwent unilateral ODRS were enrolled and followed-up for one year. They were divided into two groups based on the contralateral disease: the anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR). Postoperative evaluation included clinical and MRI evaluation. Indices measured were unilateral intermaxillary distance (UID), visual analogue scale (VAS), disc length (DL), condylar height (CH), and disc-condyle angle (DCA). Paired t tests were used to compare the clinical and MRI indices between different time points. RESULTS: Ninety-six patients were enrolled, including 47 in the ADDWR group and 49 in the ADDWoR group. One-year post-surgery, ODRS led to significant increases in MMO, DL, and CH, and decrease in VAS and DCA on the operated side (P < 0.05). In ADDWR group, UID, DL, and CH increased significantly, and VAS decreased (P < 0.05), with no significant change in DCA (P > 0.05). In ADDWoR group, clinical and MRI variables worsened slightly, except for UID, which remained unchanged (P > 0.05). CONCLUSIONS: ODRS is a promising method for correcting TMJ ID and may improve condition of ADDWR and decrease progress of ADDWoR at the contralateral joint. Preoperative bilateral TMJ evaluation is essential for better outcomes. CLINICAL RELEVANCE: ODRS can effectively treat TMJ ID and produce adaptive changes in the contralateral ID, for which continuous monitoring of the contralateral joint is essential.

The Importance of Early Diagnosis and Treatment in Septic Arthritis of the Temporomandibular Joint: A Case Report.

Septic arthritis of the temporomandibular joint (SATMJ), primarily caused by bacterial infections, is a rare condition with a diverse etiology that is inadequately documented in the literature, resulting in the absence of standardized treatment protocols. Its nonspecific clinical presentation often leads to misdiagnosis as other temporomandibular disorders, delaying diagnosis and treatment and potentially causing severe complications in the absence of established therapeutic guidelines. The main objective of this article is to report a case of a 61-year-old female with diabetes who was undergoing prolonged corticosteroid therapy and presented with pain, swelling in the right pre-auricular area, and progressive limitation in mouth opening, with no history of facial trauma, where the early diagnosis and isolation of Staphylococcus aureus after a single-port arthrocentesis prompted the timely adjustment of the treatment regimen, significantly influencing the outcome by mitigating the risk of complications. Additionally, this report includes a comprehensive literature review, highlighting the crucial importance of this prompt intervention to achieve a favorable clinical outcome.

Chondrogenic potential of superficial versus cartilage layer cells of the temporomandibular joint condyle in photopolymerizable gelatin-based hydrogels.

The objectives of this study were to compare the chondrogenic potential of cells derived from different layers of Mandibular condyle cartilage and to gain further understanding of the impact of chondrogenic cues when embedded into a novel hydrogel scaffold (PGH, a polymer blend of poly (ethylene glycol), gelatin, and heparin) compared to a gelatin hydrogel scaffold (GEL). Cartilage layer cells (CLCs) and fibroblastic superficial layer cells (SLCs) were harvested from the mandibular condyle of boer goats obtained from a local abattoir. After expansion, cells were seeded into PGH and GEL hydrogels and cultured in chondrogenic media for 3 weeks. Scaffolds were harvested at 0, 1, and 3 week(s) and processed for gross appearance, histochemical, biochemical, and mechanical assays. In terms of chondrogenesis, major differences were observed between scaffold materials, but not cell types. Glycosaminoglycan (GAG) staining showed GEL scaffolds deposited GAG during the 3 week period, which was also confirmed with the biochemical testing. Moreover, GEL scaffolds had significantly higher compressive modulus and peak stress than PGH scaffolds at all time points with the largest difference seen in week 3. It can be concluded that GEL outperformed PGH in chondrogenesis. It can also be concluded that materials play a more important role in the process of chondrogenesis than the tested cell populations. Fibroblastic SLCs were shown to have similar chondrogenic potential as CLCs cells, suggesting a rich pool of progenitor cells in the superficial fibroblastic layer capable of undergoing chondrogenesis given appropriate physical and chemical cues.

Amyloid-ß peptide treatment reverses bone loss in the mandibular condyle via Wnt signalling pathway.

Objective: To explore the effect of amyloid-ß peptide (Aß) on mandibular condyle to develop a new treatment for postmenopausal women with Temporomandibular joint osteoarthritis. Methods: A murine bone loss model was established by ovariectomy. Microstructure parameters of the condyle were measured by microcomputed tomography before and after intraperitoneal injection with Aß. Flow cytometry, Alizarin red staining, RT-qPCR assays, FITC/PI staining, Oil Red O staining and western blotting were used to evaluate the effect of Aß on the osteogenic differentiation of mouse bone marrow stromal stem cells (mBMSCs). Results: In vivo, condylar microstructure parameters increased. Serum osteoprotegerin and procollagen type 1 N propeptide increased in a dose-dependent manner after the injection of Aß, which were opposite the changes observed in c-terminal telopeptides of type I collagen, tumor necrosis factor-α and the high serum level of leptin. In vitro, Aß promoted calcium nodule formation in the cells. The expression of ALP, Runx2, osteorix and osteocalcin increased significantly. The expression of mRNAs related to the Wnt signaling pathway was significantly upregulated, which could be blocked by DKK1. Conclusion: Aß can reverse bone loss in the mandibular condyle in ovariectomized mice through promoting the osteogenic differentiation of mBMSCs via the Wnt pathway.

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.

Estrogen Hormones' Implications on the Physiopathology of Temporomandibular Dysfunction.

Background/Objectives: Temporomandibular dysfunction syndrome consists of several disorders of the masticatory system, namely those of the muscles, the joint itself, as well as the dental and periodontal system. This syndrome is often characterized by pain and an inability to perform functions within the dental-maxillary apparatus, which creates a certain degree of disability in patients. Women are more susceptible to this syndrome than men and hormonal factors, particularly estrogen, are central to its etiology and physiopathology. Methods: A comprehensive literature search was conducted using PubMed/MEDLINE, Scopus, Embase, and Web of Science databases regarding articles published from January 2008 to December 2023. Two authors conducted searches in the mentioned databases based on a pre-established search strategy using agreed-upon keywords. Additionally, each review author performed the selection process of eligible studies based on established inclusion criteria. The Newcastle-Ottawa scale and Risk of Bias tool 2 were used to assess each article for its methodological quality. Results: Of the 1030 records found in the four bibliographic databases, 22 studies were included in this review. Polymorphism in the alpha estrogen receptor appears to be significantly more prevalent in women with temporomandibular dysfunction, suggesting a genetic predisposition. There is a significant role of estrogen in the physiopathology of TMD-related pain. Women with polycystic ovary syndrome (PCOS) have a significantly higher incidence of TMD, accompanied by elevated inflammatory factors and decreased progesterone levels. In premenopausal women, there is scientific relevance to the association between beta-estradiol levels and TMD development and progression. The effects of estrogen hormones on temporomandibular dysfunction remain highly debated and challenging. Conclusions: These findings emphasize the importance of considering hormonal factors, genetic predisposition, and reproductive life stages in understanding and managing temporomandibular dysfunction. Further research is needed to elucidate the specific mechanisms underlying these associations.