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.

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.

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.

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.

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.

Animal models of temporomandibular joint heterotopic ossification: a scoping review.

There are few animal models for heterotopic ossification of the temporomandibular joint (TMJ-HO). This scoping review provides an overview of current knowledge on the induction methods and specific conditions required to produce TMJ-HO in various animal models. Two independent reviewers selected papers from the PubMed, Web of Science, and Cochrane Library databases. The inclusion criteria were articles in English, in vivo studies, and a TMJ-HO induction method. Observational, in vitro, human studies, reviews, and book chapters were excluded. Twenty-four publications were included. HO was surgically, genetically, or chemically induced through single or combined defects in the condyle, articular disc, and temporal bone in animal models (sheep=9 studies, mouse=5, rat=4, rabbit=2, pig=2, goat=1, dog=1, monkey=1) specific for traumatic TMJ-HO (n=4), ankylosis (n=9), osteoarthritis (n=8), experimental disc perforation (n=1), status post-TMJ replacement (n=1), and status post bilateral sagittal split osteotomy (n=1). TMJ-HO remains challenging to study due to its multifactorial etiology and largely unknown pathogenesis, which varies between species. There is a need for more accurate, reproducible animal models that can be extrapolated to human TMJ-HO and a consolidated clinical classification system to allow for meaningful future research.

Can treatment with chondroitin and glucosamine sulphate prevent changes in the articular disc caused by temporomandibular joint osteoarthritis?

BACKGROUND: Chondroitin and glucosamine sulphates (CGS) are considered structure-modifying drugs and have been studied in the prevention, delay or reversal of structural morphological changes in joints caused by osteoarthritis. OBJECTIVE: The aim of the present study was to investigate the action of CGS on the progression of chemically induced osteoarthritis in the temporomandibular joint (TMJ) of rabbits by evaluating the serum levels of tumour necrosis factor (TNF-α) and collagen in the articular discs. MATERIALS AND METHODS: A sample of 36 male rabbits was divided into three groups: control (CG), osteoarthritis (OG) and treatment (TG). The disease was induced by intra-articular injection of sodium monoiodoacetate (10 mg/mL) in the OG and TG groups bilaterally. After 10 days, the TG animals received subcutaneous injection of chondroitin sulphates and glucosamine (7.5 mg/kg) and the OG and CG received saline solution (50 µL). Euthanasia times were subdivided into 40 and 100 days. Collagen quantification was performed by biochemical and histological analysis and for the quantification of serum levels of TNF-α, an enzyme immunoassay was used. RESULTS: The TG showed an increase in the collagen area of the articular disc when compared to the CG and the OG. The increase collagen concentration in the discs did not show a statistically significant difference between the groups. Post-treatment TNF-α levels were significantly lower in TG compared to OG. CONCLUSIONS: The results indicate that CGS treatment delayed the degeneration of the collagen in the TMJ articular disc and reduced serum TNF-α levels, indicating a preventive effect on OA progression.

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.

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.

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.

Corticosteroids for the Treatment of Internal Temporomandibular Joint Disorders: A Systematic Review and Network Meta-Analysis.

Background: We evaluated the comparative effectiveness of all intra-articular injection corticosteroids for treating internal temporomandibular joint (TMJ) disorders. Methods: We searched MEDLINE, CENTRAL, EMBASE, SCOPUS, and LILACS through December 2023. We included randomized clinical trials (RCTs) enrolling patients with symptomatic internal disorders of the TMJ comparing any type of intra-articular corticosteroid therapy against another or to another minimally invasive therapy. The outcomes of interest were pain, range of mandibular motion (RoM), quality of life (QoL) and adverse effects at 1, 3, 6, and 12 months. We assessed the risk of bias using the Cochrane Collaboration's tool. We conducted a frequentist network meta-analysis and assessed the certainty of the evidence (CoE) using GRADE. Results: We included 20 RCTs enrolling 810 participants, which assessed five corticosteroids alone or combined with arthrocentesis or hyaluronic acid. Based on moderate CoE, betamethasone is among the most effective corticosteroids for reducing pain at one (mean difference compared to arthrocentesis [MD], -3.80; 95% confidence interval [CI], -4.55 to -3.05) and three months (MD, -2.74; 95%CI, -3.42 to -2.06), and arthrocentesis plus dexamethasone at six months (MD, -0.80; 95%CI, -1.57 to -0.03). There was no convincing evidence that any intervention was better than arthrocentesis for improving the RoM and QoL at any follow-up time. Methylprednisolone may be more harmful than arthrocentesis for adverse effects. Discussion: Betamethasone and arthrocentesis plus dexamethasone are the most effective in managing pain in the short and medium term compared to arthrocentesis (moderate CoE). Decisions about their use should consider other factors, such as costs, feasibility, and acceptability. Future research should consider QoL as an outcome and assess participants at longer follow-up periods.

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.

Syndecan-4 inhibition attenuates cartilage degeneration in temporomandibular joint osteoarthritis.

BACKGROUND: Syndecan 4 (SDC4), a type I transmembrane proteoglycan, serves as a critical link between chondrocytes and the extracellular matrix. OBJECTIVE: This study aimed to explore the role of SDC4 in cartilage degeneration of temporomandibular joint osteoathritis (TMJOA). METHODS: Condylar chondrocytes were stimulated with varying concentrations of recombinant rat interleukin-1ß (rrIL-1ß) and SDC4 small interfering RNA (si-SDC4). Anti-SDC4 ectodomain-specific antibodies or IgG were intra-articularly administrated in a TMJOA model rats. SDC4 conditional knockout (SDC4-cKO) and Sdc4flox/flox mice were induced TMJOA. Cartilage degeneration was assessed using haematoxylin & eosin (H&E) and safranin O (SO) staining. Protein levels of SDC4, matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase with a thrombospondin motifs 5 (ADAMTS5), tumour necrosis factor α (TNFα), type II collagen (Col-II), aggrecan (ACAN), cleaved caspase 3 (CASP3), Ki67 and related pathways in condylar cartilage were evaluated by immunohistochemical (IHC) staining or western blot assays. RESULTS: SDC4 expression was evidently increased in MIA-model animals compared to control groups. rrIL-1ß stimulation increased the expression of SDC4, MMP3 and ADAMTS5 expression in chondrocytes, while decreasing the expression of Col-II. These effects were reversed by si-SDC4 in vitro. In vivo, SDC4 blockade reduced the death of chondrocytes and the loss of cartilage matrix, which was evidenced by increased expression of Col-II and ACAN, and a decrease in SDC4, MMP13 and cleaved-CASP3-positive cells. Furthermore, the protein levels of ACAN and Ki67 were elevated, and the ERK1/2 and P38 signalling pathways were activated following SDC4 inhibition. CONCLUSIONS: SDC4 inhibition significantly ameliorates condylar cartilage degeneration, which was mediated, at least partly, through P38 and ERK1/2 signalling. Inhibition of SDC4 may be of great value for the treatment of TMJOA.

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.

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.

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.

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.

17ß-estradiol promotes the progression of temporomandibular joint osteoarthritis by regulating the FTO/IGF2BP1/m6A-NLRC5 axis.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJOA) is a degenerative cartilage disease. 17ß-estradiol (E2) aggravates the pathological process of TMJOA; however, the mechanisms of its action have not been elucidated. Thus, we investigate the influence of E2 on the cellular biological behaviors of synoviocytes and the molecular mechanisms. METHODS: Primary fibroblast-like synoviocytes (FLSs) isolated from rats were treated with TNF-α to establish cell model, and phenotypes were evaluated using cell counting kit-8, EdU, Tanswell, enzyme-linked immunosorbent assay, and quantitative real-time PCR (qPCR). The underlying mechanism of E2, FTO-mediated NLRC5 m6A methylation, was assessed using microarray, methylated RNA immunoprecipitation, qPCR, and western blot. Moreover, TMJOA-like rat model was established by intra-articular injection of monosodium iodoacetate (MIA), and bone morphology and pathology were assessed using micro-CT and H&E staining. RESULTS: The results illustrated that E2 facilitated the proliferation, migration, invasion, and inflammation of TNF-α-treated FLSs. FTO expression was downregulated in TMJOA and was reduced by E2 in FLSs. Knockdown of FTO promoted m6A methylation of NLRC5 and enhanced NLRC5 stability by IGF2BP1 recognition. Moreover, E2 promoted TMJ pathology and condyle remodeling, and increased bone mineral density and trabecular bone volume fraction, which was rescued by NLRC5 knockdown. CONCLUSION: E2 promoted the progression of TMJOA.

Does intra-articular injection of platelet-rich plasma/platelet-rich fibrin improve outcomes after temporomandibular joint arthrocentesis? A systematic review and meta-analysis.

Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) have been used as adjuncts to temporomandibular joint (TMJ) arthrocentesis but without any high-quality evidence. This systematic review collated data from published randomised controlled trials (RCTs) to provide level-1 evidence on its efficacy. Trials published on the databases of PubMed, Scopus, Embase, CENTRAL, and Web of Science up to 4 August 2023 and comparing intra-articular PRP/PRF with control after TMJ arthrocentesis were eligible. Primary outcomes were pain and maximal mouth opening (MMO). Twelve RCTs were included. Pooled analysis showed that pain scores were significantly reduced with the use of PRP/PRF as compared with control at one month (MD: -0.96 95% CI: -1.58 to -0.35 I2 = 86%), three months (MD: -1.22 95% CI: -1.86 to -0.59 I2 = 85%), and ≥six months (MD: -1.61 95% CI: -2.22 to -1.00 I2 = 88%). Similarly, MMO was significantly improved in the PRP/PRF group at one month (MD: 2.40 95% CI: 1.02 to 3.77 I2 = 88%), three months (MD: 3.17 95% CI: 1.63 to 4.72 I2 = 91%), and ≥six months (MD: 2.98 95% CI: 1.86 to 4.10 I2 = 75%) as compared with the control group. Subgroup analysis for PRP and PRF failed to show any difference in outcomes. Moderate quality evidence suggests that PRP and PRF may significantly improve pain and MMO when used as adjuncts to TMJ arthrocentesis. Due to the small effect size, the clinical significance of the results is questionable. The high heterogeneity in PRP/PRF preparation methods is a significant limitation.