MRI assessment and histopathologic evaluation of subchondral bone remodeling in temporomandibular joint osteoarthritis: a retrospective study

Nomogram for predicting postoperative temporomandibular joint degeneration after mandibulectomy for oral cavity cancer: a study on patients using CT and MRI data

The aim of this study was to develop a model for predicting the risk of postoperative temporomandibular joint osteoarthritis (TMJOA) in patients receiving a segmental or marginal mandibulectomy for oral cavity cancer . A total of 371 patients with buccal or gingival cancer who underwent mandibulectomy were included in this retrospective cohort study. Demographic data, computed tomography, and magnetic resonance images were reviewed. Univariate and multivariate Cox regression analyses were performed to develop a nomogram to predict post-mandibulectomy TMJOA. TMJOA was identified in 81 of the 371 patients at 2 years and 107 at 4 years. The predictors of post-mandibulectomy TMJOA were segmental mandibulectomy (hazard ratio (HR) 2.51, 95% confidence interval (CI) 1.64-3.83, P < 0.001), age ≥ 62.5 years (HR 2.28, 95% CI 1.53-3.40, P < 0.001), BMI < 24.1 kg/m2 (HR 2.13, 95% CI 1.45-3.13, P < 0.001), and American Joint Committee on Cancer stage IVa/IVb (HR 2.21, 95% CI 1.38-3.56, P = 0.001). The nomogram developed in this study exhibited good predictive capacity (area under the curve 0.742, 95% CI 0.679-0.804). The proposed model for predicting post-mandibulectomy TMJOA in patients with buccal or gingival cancer can identify high-risk individuals for early preventive oral rehabilitation.

Unveiling MRI-based structural phenotypes in temporomandibular joint osteoarthritis: implications for clinical practice and research

INTRODUCTION

Osteoarthritis (OA) is a progressive degenerative disease characterized by the gradual degradation of cartilage, remodeling of subchondral bone, synovitis, and chronic pain. This condition impacts various large and small joints, including the temporomandibular joint (TMJ). However, addressing OA, particularly in impeding or reducing disease progression, is challenging due to its clinical and imaging heterogeneity. Authors are increasingly suggesting that this heterogeneity involves different phenotypes or subpopulations, discernible by variations in the disease's pathophysiology and structural manifestations. Even within the TMJ, these phenotypes may display distinct clinical features, laboratory parameters, biochemical markers, and imaging criteria. Recent research has proposed MRI as a reference standard for TMJ OA, highlighting its substantial agreement with histopathological changes. MRI-based phenotypes offer a promising avenue for understanding disease progression and treatment response, potentially providing valuable insights for prognosis and treatment planning.

OBJECTIVE

This article introduces the ROAMES-TMJ (Rapid OsteoArthritis MRI Eligibility Score for TMJ) to assess the structural eligibility of individuals for inclusion in TMJ OA clinical trials.

Temporomandibular joint degenerative changes following mandibular fracture: a computed tomography-based study on the role of condylar involvement

OBJECTIVES

This study assessed the incidence of postfracture radiological temporomandibular joint (TMJ) degeneration in patients with different types of mandibular fractures, focusing on the impact of condylar fractures.

METHODS

This retrospective review included patients diagnosed as having mandibular fractures from 2016 to 2020 who had undergone initial computed tomography (CT) and a follow-up CT scan at least 1-month postfracture. Patient demographics, fracture details, treatment methods, and radiological signs of TMJ degeneration on CT were analyzed to identify risk factors for postfracture TMJ degeneration, with a focus on condylar head fracture and non-head (condylar neck or base) fractures.

RESULTS

The study included 85 patients (mean age: 38.95 ± 17.64 years). The per-patient analysis indicated that the incidence of new radiologic TMJ degeneration on CT was significantly the highest (p < 0.001) in patients with condylar head fractures (90.91%), followed by those with non-head condylar fractures (57.14%), and those without condylar involvement (24.49%). The per-joint analysis indicated nearly inevitable degeneration (93.94%) in 33 TMJs with ipsilateral condylar head fractures. For the remaining 137 TMJs, multivariate logistic regression revealed that other patterns (ipsilateral non-head, contralateral, or both) of condylar fractures (odds ratio (OR) = 3.811, p = 0.007) and the need for open reduction and internal fixation (OR = 5.804, p = 0.005) significantly increased the risk of TMJ degeneration.

CONCLUSIONS

Ipsilateral non-head condylar fractures and contralateral condylar fractures are associated with a high risk of postfracture TMJ degeneration. Indirect trauma plays a vital role in postfracture TMJ degeneration.

MRI of Temporomandibular Joint Disorders: A Comparative Study of 0.55 T and 1.5 T MRI

OBJECTIVES

Temporomandibular disorders (TMDs) are common and may cause persistent functional limitations and pain. Magnetic resonance imaging (MRI) at 1.5 and 3 T is commonly applied for the evaluation of the temporomandibular joint (TMJ). No evidence is available regarding the feasibility of modern low-field MRI for the assessment of TMDs. The objective of this prospective study was to evaluate the image quality (IQ) of 0.55 T MRI in direct comparison with 1.5 T MRI.

MATERIALS AND METHODS

Seventeen patients (34 TMJs) with suspected intraarticular TMDs were enrolled, and both 0.55 and 1.5 T MRI were performed on the same day. Two senior readers independently evaluated the IQ focusing on the conspicuity of disc morphology (DM), disc position (DP), and osseous joint morphology (OJM) for each joint. We analyzed the IQ and degree of artifacts using a 4-point Likert scale (LS) at both field strengths. A fully sufficient IQ was defined as an LS score of ≥3. Nonparametric Wilcoxon test for related samples was used for statistical comparison.

RESULTS

The median IQ for the DM and OJM at 0.55 T was inferior to that at 1.5 T (DM: 3 [interquartile range {IQR}, 3-4] vs 4 [IQR, 4-4]; OJM: 3 [IQR, 3-4] vs 4 [IQR 4-4]; each P < 0.001). For DP, the IQ was comparable (4 [IQR 3-4] vs 4 [IQR 4-4]; P > 0.05). A sufficient diagnostic IQ was maintained for the DM, DP, and OJM in 92% of the cases at 0.55 T and 100% at 1.5 T. Minor image artifacts (LS score of ≥3) were more prevalent at 0.55 T (29%) than at 1.5 T (12%).

CONCLUSIONS

Magnetic resonance imaging of the TMJ at 0.55 T yields a lower IQ than does MRI at 1.5 T but maintains sufficient diagnostic confidence in the majority of patients. Further improvements are needed for reliable clinical application.

Loss of Slc39a12 in hippocampal neurons is responsible for anxiety-like behavior caused by temporomandibular joint osteoarthritis

Background

An evident association between mood disorders and TMJ dysfunction has been demonstrated in previous studies. This study observed both the behavioral changes and the pathological changes in hippocampal tissue of rats in an animal model of TMJ-OA by injecting MIA into TMJ.

Methods

Eighteen SD rats were randomly assigned to the NC group and the MIA groups. A TMJ-OA model was established to assess the HWT in the TMJ region, and the rats were subjected to the OFT and EPM. HE, O-fast green staining, qRT-PCR and immunofluorescence were used to detect condylar damage. Serum and hippocampal oxidative stress levels were detected. Functions of genes obtained by RNA-Seq were investigated using H2O2, ZnCl2 and transfection of siRNA on HT22 cells.

Results

Injection of MIA resulted in disorganization of the chondrocyte layer on the condylar surface of rats, with reduced synthesis and increased degradation of the condylar cartilage matrix and reduced HWT. The results of the OFT and EPM showed that the rats in the MIA group developed anxiety-like behavior during the sixth week of MIA injection. Increased Nox4 expression, decreased SOD2 expression, elevated MDA level, and reduced GSH level were detected in serum and hippocampal neurons in the MIA group, with nuclear pyknosis and reduced Nissl bodies observed in neurons. The expression of Slc39a12 in hippocampal neurons of rats in the MIA group decreased. Slc39a12 knockdown in HT22 cells induced increased Nox4 expression, decreased SOD2 expression, increased MDA level, and reduced GSH and intracellular Zn2+. Oxidative stress in HT22 cells after transfection and H2O2 stimulation was reversed when ZnCl2 was added.

Conclusion

Loss of Slc39a12 in hippocampal neurons results in cellular oxidative stress, further leading to neuronal damage. This may potentially explain how TMJ-OA triggers anxiety-like behavior in rats.

Is magnetic resonance imaging or cone beam computed tomography alone adequate for the radiological diagnosis of symptomatic temporomandibular joint osteoarthritis? A retrospective study

This study was performed to compare the diagnostic accuracy of cone beam computed tomography (CBCT) alone and magnetic resonance imaging (MRI) alone in patients with clinical symptoms of temporomandibular joint osteoarthritis (TMJ-OA). Fifty-two patients (83 joints) with clinical signs of TMJ-OA were included in the study. Two examiners evaluated CBCT and MRI images. McNemar and kappa tests and Spearman's correlation analysis were applied. Radiological findings of TMJ-OA were detected in all 83 joints on CBCT or MRI . Seventy-four joints (89.2%) were positive for degenerative osseous changes on CBCT. MRI findings were positive in 50 joints (60.2%). Osseous changes were found in 22 joints, joint effusion in 30 joints, and disc perforation/degeneration in 11 joints on MRI. CBCT was more sensitive than MRI in detecting condylar erosion (P = 0.001), osteophyte (P = 0.001), and flattening (P = 0.002) and flattening of the articular eminence (P = 0.013) . Poor agreement (κ = -0.21) and weak correlations were found between CBCT and MRI. The study findings suggest that CBCT is superior to MRI in evaluating osseous changes of TMJ-OA, and that CBCT is more sensitive than MRI in detecting condylar erosion, condylar osteophyte, and flattening of the condyle and articular eminence.

Recent Advances in Animal Models, Diagnosis, and Treatment of Temporomandibular Joint Osteoarthritis

Temporomandibular joint osteoarthritis (TMJOA) is a gradual degenerative jaw joint condition. Until recent years, TMJOA is still relatively unrecognized and ineffective to be treated. Appropriate animal models with reliable detection methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. In this study, we summarized common animal models of TMJOA created by chemical, surgical, mechanical, and genetical approaches. The relevant pathological symptoms and induction mechanisms were outlined. In addition, different pathological indicators, furthermore, emerging therapeutic regimens, such as intra-articular drug delivery and tissue engineering-based approaches to treat TMJOA based on these animal models, were summarized and updated. Understanding the physiology and pathogenesis of the TMJOA, together using various ways to diagnose the TMJOA, were elaborated, including imaging techniques, molecular techniques for detecting inflammatory cytokines, histochemical staining, and histomorphometry measures. A more reliable diagnosis will enable the development of new prevention and more effective treatment strategies and thereby improve the quality of life of TMJOA patients. Impact statement Temporomandibular joint osteoarthritis (TMJOA) affects 8 to 16 percent of the population worldwide. However, TMJOA is still relatively unrecognized and ineffective to be treated in the clinic. Appropriate animal models with reliable diagnostic methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. We herein summarized common animal models of TMJOA and various ways to diagnose the TMJOA. More importantly, emerging therapeutic regimens to treat TMJOA based on these animal models were summarized. With the aid of strategies listed, more effective treatment strategies will be developed and thereby improve the life quality of TMJOA patients.

Chondrocyte apoptosis in temporomandibular joint osteoarthritis promotes bone resorption by enhancing chemotaxis of osteoclast precursors

OBJECTIVE

This study aimed to explore the effect and mechanism of chondrocyte apoptosis on the chemotaxis of osteoclast precursors (OCPs) during bone destruction.

DESIGN

The relationship between cartilage and bone destruction was verified with a rat temporomandibular joint osteoarthritis (TMJOA) model. The pan-caspase inhibitor Z-VAD-FMK (ZVAD) was applied to confirm the chemotactic effect of chondrocyte apoptosis on OCPs. Synthesis and release of the key chemokine CX3CL1 in apoptotic and non-apoptotic chondrocytes was assessed with IHC, IF, WB, and ELISA. The function of CX3CL1-CX3CR1 axis in the chemotaxis of OCPs was examined by CX3XR1 inhibitor AZD8797 (AZD) and si-CX3CL1. The regulatory effect of p38 MAPK on CX3CL1 release was verified by p38 inhibitor PH-797804.

RESULTS

A temporal and spatial association between cartilage degradation and bone resorption was found in the TMJOA model. The caspase-dependent chondrocyte apoptosis promoted chemotaxis of OCPs, which can be restrained by ZVAD. CX3CL1 was significantly upregulated when chondrocytes underwent apoptosis, and it played a critical role in the recruitment of OCPs, blockage of CX3CL1-CX3CR1 axis resulted in less bone resorption in TMJOA. P38 MAPK was activated in apoptotic chondrocytes, and had a regulatory effect on the synthesis and release of CX3CL1. After inhibition of p38 by PH-797804, the chemotactic effect of apoptotic chondrocytes on OCPs was limited.

CONCLUSIONS

This study indicates that apoptosis of chondrocytes in TMJOA enhances chemotaxis of OCPs toward osteoclast precursors through upregulation of the p38-CX3CL1 axis, thereby promoting the activation of local osteoclasts.

Interdisciplinary Approach to the Temporomandibular Joint Osteoarthritis-Review of the Literature

Background and objectives: There are an increasing number of patients applying for dental treatment who suffer from temporomandibular joint osteoarthritis (TMJOA). Osteoarthritis may be the cause of the pain in the area of temporomandibular joints, but its course may also be absolutely asymptomatic. The aim of this study was to present an interdisciplinary approach to TMJOA, including current diagnostics and treatment modalities on the basis of the available literature. Materials and Methods: PubMed and Scopus databases were analyzed using the keywords: ((temporomandibular joint AND osteoarthritis) AND imaging) and ((temporomandibular joint AND osteoarthritis) AND treatment). The bibliography was supplemented with books related to the temporomandibular joint. After screening 2450 results, the work was based in total on 98 publications. Results and Conclusions: Osteoarthritis is an inflammatory, age-related, chronic and progressive degenerative joint disease. Magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT), together with clinical symptoms, play significant roles in TMJOA diagnosis. Current MRI techniques seem to be clinically useful for assessment of bony changes in temporomandibular joint (TMJ) disorders. Treatment of TMJOA requires a complex, interdisciplinary approach. TMJOA treatment includes the cooperation of physiotherapists, rheumatologists, gnathologists, orthodontists and quite often also maxillofacial surgeons and prosthodontists. Sometimes additional pharmacotherapy is indicated. Thorough examination of TMJ function and morphology is necessary at the beginning of any orthodontic or dental treatment. Undiagnosed TMJ dysfunction may cause further problems with the entire masticatory system, including joints, muscles and teeth.

LncRNA PVT1 induces chondrocyte apoptosis through upregulation of TNF-α in synoviocytes by sponging miR-211-3p

Temporomandibular joint osteoarthritis (TMJ OA) is an important subtype of temporomandibular disorders (TMD). Articular cartilage destruction is considered a common pathological feature of TMJ OA, which is reported to be mainly induced by chondrocyte apoptosis. Synovial sterile inflammation is an initial factor of TMJ OA-associated articular cartilage destruction. Therefore, determining the mechanism of synovial membrane inflammation-induced articular cartilage destruction in TMJ OA is important for the TMJ OA therapy. In this study, we detected the function of synoviocytes in chondrocyte apoptosis under lipopolysaccharide (LPS)-induced inflammatory conditions and explored the underlying mechanism. We found that synoviocytes in inflammatory conditions facilitated LPS-induced chondrocytes apoptosis by secreting increased Tumor Necrosis Factor α (TNF-α), which was induced by long non-coding RNA plasmacytoma variant translocation 1 (PVT1) upregulation. PVT1 served as a competing endogenous RNA that sponged the microRNA miR-211-3p and prevented the inhibition of TNF-α expression. In conclusion, our in vitro study revealed that PVT1 has a previously unknown role in chondrocyte apoptosis, which may also be a mechanism underlying synoviocyte involvement in TMJ OA.

Temporomandibular joint damage in K/BxN arthritic mice

Rheumatoid arthritis (RA) is an autoimmune disease affecting 1% of the world population and is characterized by chronic inflammation of the joints sometimes accompanied by extra-articular manifestations. K/BxN mice, originally described in 1996 as a model of polyarthritis, exhibit knee joint alterations. The aim of this study was to describe temporomandibular joint (TMJ) inflammation and damage in these mice. We used relevant imaging modalities, such as micro-magnetic resonance imaging (μMRI) and micro-computed tomography (μCT), as well as histology and immunofluorescence techniques to detect TMJ alterations in this mouse model. Histology and immunofluorescence for Col-I, Col-II, and aggrecan showed cartilage damage in the TMJ of K/BxN animals, which was also evidenced by μCT but was less pronounced than that seen in the knee joints. μMRI observations suggested an increased volume of the upper articular cavity, an indicator of an inflammatory process. Fibroblast-like synoviocytes (FLSs) isolated from the TMJ of K/BxN mice secreted inflammatory cytokines (IL-6 and IL-1β) and expressed degradative mediators such as matrix metalloproteinases (MMPs). K/BxN mice represent an attractive model for describing and investigating spontaneous damage to the TMJ, a painful disorder in humans with an etiology that is still poorly understood.