Temporomandibular Joint Osteoarthritis Research Articles

Evaluation of temporomandibular joint osteoarthritis using a new FRACTURE sequence of 3.0T magnetic resonance imaging.

The purpose of this study was to determine the usefulness of a new MRI sequence, CT-like fast field echo with limited echo-spacing (FRACTURE), in diagnosing temporomandibular joint osteoarthritis compared with routine MRI temporomandibular joint (TMJ) sequences. The study sample comprised 76 patients (152 joints) who underwent MRI and CT examinations to diagnose TMJ disorders. Two specialists in oral and maxillofacial radiology assessed the bony changes of the TMJ on FRACTURE, proton density-weighted (PDw), and fat-suppression T2-weighted (T2wFS) sequences. Receiver operating characteristic curves were plotted for each sequence, and the accuracy, sensitivity, specificity, and area under the curve (AUC) were calculated. Additionally, the interobserver agreement (Cohen's kappa value) and sensitivity in assessing each osteoarthritis finding were calculated for each sequence. The FRACTURE sequence had the highest diagnostic performance, with an accuracy of 0.85, sensitivity of 0.85, specificity of 0.84, and AUC of 0.84. These values were 0.84, 0.72, 0.91, and 0.80, respectively, for the PDw sequence, and 0.83, 0.72, 0.91, and 0.79, respectively, for the T2wFS sequence. The AUC did not significantly differ between the FRACTURE and PDw sequences (Delong test, p > 0.05), but did significantly differ between the FRACTURE and T2wFS sequences (p < 0.05). For all osteoarthritis findings, the FRACTURE sequence had the highest kappa values and the highest sensitivity. FRACTURE sequencing may be a promising tool for the diagnosis of TMJ osteoarthritis compared with other conventional sequences.

Prevalence of serum vitamin D and B12, Ca, P, Mg levels and rheumatoid factor status in the patients with bilateral TMJ-OA and their correlations with clinical and radiological findings

ABSTRACT Objective To evaluate the prevalence of serum vitamin D and B12, calcium, phosphorus, magnesium levels, and rheumatoid factor (RF) status in patients with bilateral temporomandibular joint osteoarthritis (TMJ-OA) and their correlations with clinical and radiological findings. Methods The clinical and radiologic findings and serum vitamin and mineral levels of 90 patients diagnosed with bilateral TMJ-OA were recorded. Descriptive statistics and the Spearman’s Rho correlation test were performed. Results Low serum vitamin D and B12 levels were detected in 82 (91.1%) and 74 (82.2%) patients. Calcium and phosphorus levels were seen at low rates. RF status was recorded as unfavorable in all patients. Correlations were found between age and the serum vitamin and mineral levels, except phosphorus. Low serum vitamin D levels correlated with pain complaints at rest and painless MIO. Serum B12 levels correlated with condylar erosion. Serum magnesium levels correlated with painful MIO and condylar osteophyte. Conclusion Patients with bilateral TMJ-OA showed a high prevalence of low serum vitamin D and B12 levels.

FSTL1 Can Be a Promising Target in TMJ Osteoarthritis via Regulating Chondrocyte Mitophagy and Apoptosis.

Previous studies have shown that follistatin-like protein 1 (FSTL1) is elevated in the synovial fluid of osteoarthritis and whether it is associated with disease development progress in cartilage degeneration is still unclear. The experiment was performed to explore the effect and mechanism of FSTL1 on chondrocyte degeneration and its further impaction in osteoarthritis as well as its treatment method. The patients who were diagnosed with temporomandibular joint (TMJ) disc displacement and osteoarthritis (OA) group was divided into 2 groups, anterior disc displacement (ADD) without bone resorption and ADD with bone resorption group according to the radiologic examination. The ELISA kit was used to determine the expression level of FSTL1 in patients TMJ environment. The function of FSTL1 in promoting chondrocyte degeneration was tested by quantitative reverse transcription polymerase chain reaction (Rt-qPCR) and western blot. The chondrocyte apoptosis and mitophagy were further test by flow cytometry and mitosox staining by upregulating and downregulating of FSTL1. In the end, the effectiveness of regulating FSTL1 in OA procedure was further validated by hematoxylin-eosin (HE), safranin O, and immunohistochemical (IHC) staining in vivo. There were 56 samples collected from the patients were included into this study. According to the ELISA results, FSTL1 expression levels of ADD without bone resorption groups were significantly lower than that in ADD with bone resorption group. Furthermore, the rate of cell apoptosis cells and the mitophagy procedure were highly activated when FSTL1 was upregulated. The morphology analysis of mitochondria showed significant changes when FSTL1 was highly upregulated in vitro. The in vivo and in vitro experiments showed that suppressing FSTL1 could alleviate the cartilage degeneration in TMJ OA progression. To sum up, upregulated expression level of FSTL1 in synovial fluid promoted the progression of TMJ OA by upregulating accelerating the chondrocyte apoptosis and mitophagy, and suppressing the FSTL1 in TMJ can rescue the OA progression. Therefore, it may be a promising result to consider the FSTL1 as a therapeutic target in the future.

Sulfur-species in Zinc-specific Condylar Zones of a Rat Temporomandibular Joint.

In this study, we performed synchrotron-based micro-X-ray fluorescence (μ-XRF) imaging of elements Zn and S, and X-ray absorption near edge spectroscopy (XANES) coupled with μ-XRF for identification of Zn and S species in the condylar zones of a rat temporomandibular joint (TMJ). Histologic localization of Zn and hypoxia-inducible factor-1α (HIF-1α) were mapped using an optical microscope. These data were visually correlated with μ-XRF and XANES data to provide insights into plausible biological S-species in Z-enriched condylar zones of a rat TMJ. Furthermore, μ-XRF coupled with micro-X-ray diffraction (μ-XRD) was used to underline Z-incorporated biological apatite in the subchondral bone and bone of the rat TMJ. Results illustrated the potential dependence between biometal Zn and nonmetal S and their collective governance of cell and tissue functions in a zone-specific manner. Elemental Zn with organic and inorganic S-species at the cartilage-bone interface and transformation of plausible Zn-enriched mineralization kinetics of biological apatite from subchondral bone to condylar bone were ascertained using μ-XRF-XANES and μ-XRD. The coupled μ-XRF-XANES complementing with μ-XRD and immunohistology provided an informative view of S and Zn and their association with zone-specific biological pathways in situ . Understanding the spatial distributions of the main S-species with redox-inert Zn in regions of cartilage, bone, and the interface is essential for further unlocking questions surrounding formation and resorption-related biomineralization pathways as related to osteoarthritis or genetically inherited diseases. Using these complementary techniques with microspectroscopic spatial information provided insights into the associations between biometal Zn and nonmetal S and a window into detecting the plausible early-stage diagnostic biomarkers for humans with TMJ osteoarthritis.

Histopathological characterization of mandibular condyles in four temporomandibular joint osteoarthritis mouse models

ObjectiveTemporomandibular joint osteoarthritis (TMJOA) has been modeled in different ways with a lack of uniformity. We aimed to investigate four TMJOA mouse models and assess histopathological changes in condyles, which could assist in the selection of animal models in further TMJOA-related studies. DesignFour TMJOA mouse models were established, including unilateral hyperocclusion, discectomy, monosodium iodoacetate injection and aged model. Bilateral condyles were collected at different time points. The condylar alterations were analyzed by Micro-CT, Hematoxylin and eosin staining, Toluidine blue staining, Safranin O staining, Trap staining, immunofluorescence staining, immunohistochemistry staining and quantitative polymerase chain reaction. ResultsRadiographic and histopathological analysis indicated that all four methods could cause condylar degeneration successfully. Differences in morphologic and histologic changes were found among four models. The hyperocclusion model was time-dependent and the lesions got worse over time. Discectomy model presented obvious damage of cartilage and subchondral bone. Injected model showed severe inflammation and chondrocyte hypertrophy. The aged model was characterized by decreased of proteoglycan and osteolysis. ConclusionsThe four methods had different characteristics and applicability. The harvest time affected the degree of cartilage degradation. Hyperocclusion was suited to explore the early-stage of TMJOA. Discectomy present advantages in investigating the long-term restoration of cartilage and subchondral bone. Monosodium iodoacetate-injection was appropriate for screening the agents for inflammatory relief. The aged model more naturally facilitated discovering underlying mechanisms in primary TMJOA. Unilateral modeling methods could initiate contralateral condylar alterations. The TMJOA models should be selected based on experimental requirements and applicability of each model.

Characteristics of Temporomandibular Joint Osteoarthritis Patients With Condylar Erosion: A Retrospective Cross-Sectional Study.

Condylar erosion (CE) may indicate an active progressive stage of temporomandibular joint osteoarthritis (TMJOA), but no studies have analysed the characteristics of this population. This cross-sectional study analysed the characteristics of TMJOA patients with CE. A total of 267 patients were included. The severity of CE of all joints was evaluated using cone beam computed tomography (CBCT) and scored using a four-point rating scale (0-III). Patients were categorised into mild (grade I), moderate (grade II) and severe (grade III) groups. Demographic and clinical characteristics were summarised and stratified by age and erosion severity. Univariate and multivariate logistic regression analyses were performed based on the assignment of the variables. The proportion of patients under 30 years old is much higher than other age groups. Compared to adults (≥ 20 years old), a higher proportion of adolescent patients (10-19 years old) choose orthodontics department for their first consultation (p < 0.01). And adolescent patients have a higher proportion of temporomandibular joint (TMJ) noise (p < 0.05) and a lower proportion of arthralgia (p < 0.001). Significant differences exist in CE severity between adolescents and adults (p < 0.001). The severe group had the youngest patients (p < 0.05) and the highest proportion of mandibular deviation and abnormal postural habits. Patients under 30 years of age constitute a significant proportion of TMJOA cases with CE. Compared to adults, adolescent patients have more severe CE and less arthralgia. Due to obvious dental and maxillofacial deformities and milder TMJ symptoms, adolescent patients may not be aware that they have TMJ disease, potentially leading to delayed treatment.

COMPARISON OF THE EFFICACY OF ARTHROCENTESIS WITH AND WITHOUT CONCENTRATED GROWTH FACTOR INJECTIONS IN REDUCING CLINICAL SYMPTOMS IN PATIENTS WITH TEMPOROMANDIBULAR JOINT OSTEOARTHRITIS

There is a significant prevalence of temporomandibular joint (TMJ) disorders, estimated at 34% according to various sources. Given that this condition often leads to a reduced quality of life and disability, there is a pressing need to develop and implement effective treatment methods. Arthrocentesis, along with the injection of pharmacological agents—particularly platelet-rich plasma—into the joint cavity, is a recognized treatment for TMJ osteoarthritis. Recently, a third generation of platelet concentrates has been developed, which is an evolutionary advancement of the platelet-rich plasma technique. This study involved 60 patients, equally divided into control and experimental groups. The control group was treated with arthrocentesis for TMJ osteoarthritis, while the experimental group received arthrocentesis combined with intra-articular injections of concentrated growth factor. The effectiveness of the treatments was evaluated using the visual analogue scale (VAS) for pain and measuring maximum mouth opening. The study results showed a 74.22% reduction in VAS scores in the control group and a 79.87% reduction in the experimental group (p &lt; 0.001). Maximum mouth opening increased by 17.84% in the control group and by 20.53% in the experimental group (p &lt; 0.001). Both treatment methods demonstrated significant clinical efficacy (p &lt; 0.001). In our opinion, the use of arthrocentesis with concentrated growth factor injections for the treatment of TMJ osteoarthritis is clinically justified and more effective than arthrocentesis alone.

AI and radiologist assessments on the prevalence of TMJ osteoarthritis using radiographic images: A comparative study

Objectives: This study aims to address the significant discomfort and functional impairment associated with temporomandibular joint osteoarthritis (TMJ OA), which negatively impacts the quality of life. It emphasizes the importance of prompt diagnosis and explores the potential of an Artificial Intelligence (AI) system to enhance TMJ OA diagnosis. Methods: The prevalence of TMJ OA was evaluated using 3 diagnostic tools: the gold standard, the AI model, and an examiner. In total, 132 patients who performed 190 cone-beam computed tomography (CBCT) images were included. Results: The prevalence of TMJ OA was 62.11% using the gold standard, 63.68% using the AI model, and 58.42% when assessed by the examiner. No gender variation in TMJ OA diagnosis was reported (p-value&gt;0.05). Age variations were reported with the gold standard and the examiner diagnosis. When compared to the gold standard, the AI model had remarkable sensitivity (97.46%) and specificity (91.67%). Conclusions: The AI model shows promise in enhancing the accuracy of TMJ OA diagnosis, offering potential benefits for early detection and improved patient outcomes.

Automatic detection of temporomandibular joint osteoarthritis radiographic features using deep learning artificial intelligence. A Diagnostic accuracy study

ObjectiveThe purpose of this study was to investigate the diagnostic performance of a neural network Artificial Intelligence model for the radiographic confirmation of Temporomandibular Joint Osteoarthritis in reference to an experienced radiologist. Materials and MethodsThe diagnostic performance of an AI model in identifying radiographic features in patients with TMJ-OA was evaluated in a diagnostic accuracy cohort study. Adult patients elected for radiographic examination by the Diagnostic Criteria for Temporomandibular Disorders decision tree were included. Cone-beam computed Tomography images were evaluated by object detection YOLO deep learning model. The diagnostic performance was verified against examiner radiographic evaluation. ResultsThe differences between the AI model and examiner were non-significant statistically, except in the subcortical cyst (P=0.049*). AI model showed substantial to near-perfect levels of agreement when compared to those of the examiner data. Regarding each radiographic phenotype, the AI model reported favorable sensitivity, specificity, accuracy, and highly statistically significant Receiver Operating Characteristic (ROC) analysis (p<0.001). Area Under Curve ranged from 0.872, for surface erosion, to 0.911 for subcortical cyst. ConclusionAI object detection model could open the horizon for a valid, automated, and convenient modality for TMJ-OA radiographic confirmation and radiomic features identification with a significant diagnostic power.

Identification of potential immune-related genes and infiltrations in temporomandibular joint osteoarthritis.

The aim of this study was to investigate the potential inflammatory cytokines and chemokines markers for temporomandibular joint osteoarthritis (TMJOA) diagnosis using a bioinformatics analysis. The differentially expressed genes of mRNA (DEGs) and transcripts of lncRNA (DETs) were identified between TMJOA samples and normal controls curated from GSE205389 by the "DESeq. 2" R package. KEGG and GO were conducted using the R package "ggplot2" and "clusterProfiler". A PPI network was constructed to identify hub genes by using the STRING and Cytoscape. The co-expression network was constructed between mRNA and lncRNA to check the potential regulation and function of lncRNA on protein-coding genes. Finally, the immune cell infiltration analysis was conducted with CIBERSORTx and confirmed with xCells. The authors identified 171 DEGs and DETs, of which the DEGs were closely related to immune response, T-cell activation, cytokine-cytokine-receptor interaction, and the muscle system process. PPI network of the DEGs screened the top 10 hub genes, including IL6, IL1B, IL10, CCL2, CCL5, CXCL1, CXCL10, ICAM1, CSF1 and MMP1. Additionally, the immune cell infiltration analysis showed that CD8+ T cells, M1 macrophage and B cells infiltration were increased in TMJOA samples. Finally, the authors demonstrated that the co-expression between mRNA and lncRNA was mainly enriched in inflammatory and muscle-related pathways. The authors found that immune and muscle system-related pathways as well as the immune infiltration played a significant role in the TMJOA development. Additionally, inflammatory cytokines and chemokines could be crucial markers for early-stage TMJOA diagnosis and personalized treatment strategies.

FTO in oral diseases: Functions, mechanisms, and therapeutic potential.

Fat mass and obesity-associated protein (FTO) is the first identified N6-methyladenosine (m6A) demethylase widely distributed in various tissues in adults and children. It plays an essential role in diverse mRNA-associated processes including transcriptional stability, selective splicing, mRNA translocation, and also protein translation. Recently, emerging studies have shown that FTO is involved in the genesis and development of oral diseases. However, the correlation between FTO and oral diseases and its specific regulatory mechanism still needs further study. In this review, we will summarize the discovery, distribution, gene expression, protein structure, biological functions, inhibitors, and quantifying methods of FTO, as well as its regulatory role and mechanism in oral diseases. Notably, FTO genetic variants are strongly associated with periodontal diseases (PDs), temporomandibular joint osteoarthritis (TMJOA), and obstructive sleep apnea (OSA). Besides, the latest studies that describe the relationship between FTO and PDs, head and neck squamous cell carcinoma (HNSCCs), TMJOA, and OSA will be discussed. We elaborate on the regulatory roles of FTO in PDs, HNSCCs, and TMJOA, which are modulated through cell proliferation, cell migration, apoptosis, bone metabolism, and immune response. The review will enrich our understanding of RNA epigenetic modifications in oral diseases and present a solid theoretical foundation for FTO to serve as a novel diagnosis and prognostic biomarker for oral diseases.

β-catenin Orchestrates Gli1+ Cell Fate in Condylar Development and TMJOA

The fibrocartilage stem cells (FCSCs) on the surface of the condyle play an essential role in cartilage homeostasis and regeneration. However, few well-defined stem cell markers have been identified for the analysis of FCSCs’ cell fate and regulation mechanism. In this study, we first mapped the transcriptional landscape of the condylar cartilage and identified a Gli1+ subset. Label-retaining cells and our lineage-tracing study showed that Gli1 labeled a group of FCSCs. Conditional knockout β-catenin inhibited Gli1+ cells differentiating into hypertrophic chondrocytes. In discectomy-induced temporomandibular joint osteoarthritis (TMJOA), Gli1+ cells were further activated, and their differentiation into hypertrophic chondrocytes was accelerated, which induced stem cell pool depletion. The deletion of β-catenin in Gli1+ cells preserved the FCSC pool and alleviated TMJOA cartilage degeneration. Collectively, we uncovered that a Gli1+ FCSC subpopulation and Wnt/β-catenin signaling orchestrate the Gli1+ cell fate in condyle postnatal development and TMJOA.

Adipose tissue-derived extracellular vesicles aggravate temporomandibular joint osteoarthritis associated with obesity.

Temporomandibular joint osteoarthritis (TMJ OA) is a major disease that affects maxillofacial health and is characterised by cartilage degeneration and subchondral bone remodelling. Obesity is associated with the exacerbation of pathological manifestations of TMJ OA. However, the underlying mechanism between adipose tissue and the TMJ axis remains limited. To evaluate the effects of obesity and the adipose tissue on the development of TMJ OA. The obesity-related metabolic changes in TMJ OA patients were detected by physical signs and plasma metabolites. The effects of adipose tissue-derived EVs (Ad-EVs) on TMJ OA was investigated through histological and cytological experiments as well as gene editing technology. Alterations of Ad-EVs in obese state were identified by microRNA-seq analysis and the mechanism by which EVs affect TMJ OA was explored in vitro and in vivo. Obesity and the related metabolic changes were important influencing factors for TMJ OA. Ad-EVs from obese mice induced marked chondrocyte apoptosis, cartilage matrix degradation and subchondral bone remodelling, which exacerbated the development of TMJ OA. Depletion of Ad-EVs secretion by knocking out the geranylgeranyl diphosphate synthase (Ggpps) gene in adipose tissue significantly inhibited the obesity-induced aggravation of TMJ OA. MiR-3074-5p played an important role in this process . Our work unveils an unknown link between obese adipose tissue and TMJ OA. Targeting the Ad-EVs and the miR-3074-5p may represent a promising therapeutic strategy for obesity-related TMJ OA. High-fat-diet-induced obesity aggravate the progression of TMJ OA in mice. Obese adipose tissue participates in cartilage damage through the altered miRNA in extracellular vesicles. Inhibition of miR-3074-5p/SMAD4 pathway in chondrocyte alleviated the effect of HFD-EVs on TMJ OA.

An "All-in-One" Strategy to Reconstruct Temporomandibular Joint Osteoarthritic Microenvironment Using γ-Fe2O3@TA@ALN Nanoparticles.

Current clinical strategies for the treatment of temporomandibular joint osteoarthritis (TMJOA) primarily target cartilage biology, overlooking the synergetic effect of various cells and inorganic components in shaping the arthritic microenvironment, thereby impeding the effectiveness of existing therapeutic options for TMJOA. Here, γ-Fe2O3@TA@ALN magnetic nanoparticles (γ-Fe2O3@TA@ALN MNPs) composed of γ-Fe2O3, tannic acid (TA), and alendronate sodium (ALN) are engineered to reconstruct the osteoarthritic microenvironment and mitigate TMJOA progression. γ-Fe2O3@TA@ALN MNPs can promote chondrocytes' proliferation, facilitate chondrogenesis and anisotropic organization, enhance lubrication and reduce cartilage wear, and encourage cell movement. Magnetic-responsive γ-Fe2O3@TA@ALN MNPs also exhibit pH sensitivity, which undergoes decomposition within acidic environment to release ALN on demand. Under a 0.2 T static magnetic field, γ-Fe2O3@TA@ALN MNPs accelerate the synthesis of cartilage-specific proteins, and suppress catabolic-related genes expression and reactive oxygen species generation, affording additional protection to TMJ cartilage. In TMJOA mouse models, articular injection of γ-Fe2O3@TA@ALN MNPs effectively alleviates cartilage degeneration and subchondral bone loss in short and long terms, offering promising avenues for the development of therapeutic interventions for TMJOA.

Temporomandibular Joint Pain Measurement by Bite Force and Von Frey Filament Assays in Mice.

Temporomandibular joint (TMJ) pain and osteoarthritis (OA) are common and debilitating disorders that impair patients' quality of life. The mechanisms driving diseases-related pain are poorly understood, and current treatments fail to provide effective and long-term therapeutic effects. Additionally, pain assessment in research, particularly orofacial pain, poses several challenges that complicate studies in both clinical and basic science settings. Therefore, we have established an inflammatory TMJ pain mouse model via intra-articular injection of CFA (Complete Freund's Adjuvant) and evaluated pain behaviors by bite force measurement and the von Frey filament test. Mice with CFA injection exhibited orofacial pain behaviors compared to PBS injection, including reduced bite force and head withdrawal threshold in the von Frey filament test. These methods are relatively easy to execute to have reproducible results and can be potentially extended to pain studies for other disease models related to TMJ disorders. Together, bite force, and the von Frey filament tests are reliable in measuring orofacial pain, as demonstrated in CFA injection-induced painful TMJOA mouse models.

Lipoxin A4 modulates the PKA/CREB and NF-κB signaling pathway to mitigate chondrocyte catabolism and apoptosis in temporomandibular joint osteoarthritis

Temporomandibular joint osteoarthritis (TMJ-OA) is characterized by the degradation of the extracellular matrix (ECM) in cartilage and the apoptosis of chondrocytes, which is caused by inflammation and disruptions of chondrocyte metabolism and inflammation. Lipoxin A4 (LXA4), a specialized pro-resolving mediator, has been shown to inhibit inflammation and regulate the balance between ECM synthesis and degradation. However, the therapeutic effects of LXA4 on TMJ-OA and its underlying mechanisms remain unclear. Interleukin-1 beta (IL-1β)-induced chondrocyte and surgically induced TMJ-OA rat models were established in this study. The viability of chondrocytes treated with LXA4 was evaluated with the cell counting kit-8 (CCK-8) assay, while protein levels were assessed by western blot analysis, and the apoptosis rate was evaluated with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) staining. Histological analysis was conducted to evaluate the impact of LXA4 on cartilage degradation in TMJ-OA rat models. In vitro, the qRT-PCR and western blot analysis demonstrated that LXA4 facilitated the upregulation of collagen proteins (Collagen II) and decreased expression of matrix metalloproteinases (MMP-3, and MMP-13) associated with ECM modulation. LXA4 enhanced the TMJ-OA chondrocyte viability and decreased apoptotic rate. In vivo, histology and immunohistochemistry (IHC) analysis revealed that intraperitoneal injection of LXA4 contributed to the amelioration of chondrocyte injuries and deceleration of TMJ-OA. Transcriptomic sequencing revealed that cAMP signaling pathway was up-regulated and NF-κB signaling pathway was down-regulated in LXA4 treated group. LXA4 inhibited the phosphorylation of P65 and inhibitor of nuclear factor kappa B (IκBα) proteins while enhancing the phosphorylation PKA and CREB. This study demonstrates the potential of LXA4 as a therapeutic agent for suppressing chondrocyte catabolism and apoptosis by increasing PKA/CREB activity and decreasing NF-κB signaling.

Microgel Encapsulated Mesoporous Silica Nanoparticles for Releasing Wnt16 to Synergistically Treat Temporomandibular Joint Osteoarthritis.

Temporomandibular joint osteoarthritis (TMJOA) is a commonly encountered degenerative joint disease in oral and maxillofacial surgery. Recent studies have shown that the excessive unbalanced activation of Wnt/β-catenin signaling is connected with the pathogenesis of TMJOA and due to the inability to inhibit the over-activated Wnt pathway, while Wnt16-deficient mice has a more severe Knee OA. However, the efficacy of direct intra-TMJ injection of Wnt16 for the relief of TMJOA is still not directly confirmed. Moreover, small-molecule drugs such as Wnt16 usually exhibit short-lived efficacy and poor treatment adherence. Therefore, in order to obtain a stable release of Wnt16 both in the short and long term, this study fabricates a double-layer slow-release Wnt16 carrier based on mesoporous silica nanospheres (MSNs) encased within hyaluronic acid (HA) hydrogels. The biofunctional hydrogel HA/Wnt16@MSN is analyzed both in vitro and in vivo to evaluate the treatment of TMJOA. As a result, it shows superior pro-cartilage matrix restoration and inhibition of osteoclastogenesis ability, and effectively inhibits the over-activation of the Wnt/β-catenin pathway. Taken together, biofunctional hydrogel HA/Wnt16@MSN is a promising candidate for the treatment of TMJOA.

Variation in Craniodental Pathologies Among Cercopithecoid Primates.

Pathologies of the skull and teeth are well documented for many human populations, but there are fewer studies of other primates. We contrast lesion prevalence and patterning among cercopithecoid primates and map variation onto socioecological variables. We compare craniodental lesions in six species: Nasalis larvatus (n = 54), Colobus polykomos (n = 64), Cercopithecus mitis (n = 65), Macaca fascicularis (n = 109), Theropithecus gelada (n = 13), and Papio anubis (n = 76). One of us (C.A.K.) evaluated each adult skull for multiple lesion types using standard criteria. We also tested for a relationship between lesion prevalence and cranial suture fusion (age proxy). We used nonparametric tests for sex and species differences as well as pathology co-occurrence in SPSS. Socioecological data come from previous studies. Sex differences in lesion prevalence were only detected in P. anubis. Within taxa, some lesion types co-occurred. In Macaca, the presence of caries was associated with several other lesion types. Pulp cavity exposure co-occurred with TMJ osteoarthritis in multiple taxa. Among taxa, male P. anubis had higher lesion prevalences, particularly related to the anterior dentition and facial trauma. Because we did not detect a relationship between suture fusion and lesion prevalence, we propose that craniodental lesions may also be influenced by socioecological variables such as group composition and ratio of fruit to leaves in the diet. Our findings suggest that pain from pulp cavity exposure and related dental infections may alter chewing biomechanics and contribute to onset of TMJ osteoarthritis in nonhuman primates, as seen in humans. Further, we suggest that higher lesion prevalence in male baboons is likely related to male-male competition. Skeletal lesion analysis provides useful insight into primate socioecology, particularly for rare or difficult-to-observe phenomena, and provides additional biological context for our own species.

Effects of Glucosamine in the Temporomandibular Joint Osteoarthritis: A Review.

Osteoarthritis in the temporomandibular joint (TMJ) is a chronic disease characterized by irreversible damage to articular surfaces, including inflammation, loss of articular cartilage, and subchondral bone alterations, which would be radiographically evident only in later stages. Symptomatic slow-acting so-called nutraceutical drugs have been proposed as a treatment for osteoarthritis in comparison to non-steroidal anti-inflammatory drugs (NSAID) because of their appreciable safety profile even in long-term intake. Glucosamine, being one among them, proved highly efficient in knee osteoarthritis. However, its application in TMJ osteoarthritis dates back only to 2001 and is still inconclusive in its efficiency even with systematic reviews, in restoring the structural and functional aspects of damaged TMJ. Glucosamine, being a natural compound and also a contributor to building the matrix of articular cartilage, can be utilized effectively for TMJ osteoarthritis as an adjunct along with other conventional treatment modalities available till now, which also have moderate prognosis in most of the clinical scenarios. This review summarizes data relating to the mechanism of osteoarthritis and its management using glucosamine formulations. The beneficial effects of glucosamine on the pathophysiology of TMJ osteoarthritis are possibly due to its contribution to hyaluronic acid regulation and in establishing a proper balance between anabolism/catabolism in the articular tissues.

Intramuscular Botulinum Toxin as an Adjunct to Arthrocentesis with Viscosupplementation in Temporomandibular Disorders: A Proof-of-Concept Case-Control Investigation.

The reduction in joint load is a potential beneficial factor in managing osteoarthritis of the temporomandibular joint (TMJ). This paper aims to compare the effectiveness of the intramuscular injection of botulinum toxin (BTX-A) as an adjunct to TMJ arthrocentesis plus viscosupplementation with arthrocentesis plus viscosupplementation alone in the management of TMJ osteoarthritis. A pilot clinical retrospective study examined TMJ osteoarthritis treatments. Patients were divided into two groups: Group A received BTX-A injections and arthrocentesis with viscosupplementation, while Group B received only arthrocentesis with viscosupplementation. The study assessed outcomes based on mouth opening (MO), pain at rest (PR), pain at mastication (PF), and masticatory efficiency (ME) at various time points (baseline (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4)) up to 2 months after treatment. The study included two groups, each with five patients. Group A received five weekly sessions of arthrocentesis plus viscosupplementation and a single BTX-A injection during the first arthrocentesis appointment. Group B underwent the five-session protocol of arthrocentesis plus viscosupplementation alone. MO, PF, PR, and ME improved quickly in T2 in both groups, but the improvement was of greater importance over the following weeks and lasted longer in Group A. Arthrocentesis with viscosupplementation associated with BTX-A was found to be more effective than arthrocentesis alone in improving clinical outcomes. This suggests that patients with TMJ osteoarthritis and myofascial pain may benefit from reduced muscle tone and joint load.