Temporomandibular Joint Osteoarthrosis Research Articles

Do Surgical Intervention Type and Baseline Condylar Position Affect Spatial Dimension Changes of the Temporomandibular Joint in the Surgical Correction of Skeletal Class II Deformities?

One of the key features of orthognathic surgery is altering temporomandibular joint (TMJ) condylar positions. This multivariate study aimed to identify surgical interventions and patient factors significantly associated with changes in TMJ spatial dimensions after the surgical correction of skeletal Class II deformities. This is a retrospective cohort study including patients who had undergone an isolated bilateral sagittal split ramus osteotomy (BSSO) or a bimaxillary osteotomy (BMO) for mandibular advancement and a control sample of patients treated with the removal of odontogenic cysts in the mandibular posterior region. Excluded were those who presented with specific radiographic signs of TMJ osteoarthrosis, severe facial asymmetry, or deformity secondary to trauma. The primary predictors were condylar position at baseline (anterior, concentric, and posterior), time points (T0, preoperatively; T1, immediately after surgery; and T2, 1-year follow-up), and surgical intervention type (BSSO, BMO, and control group). The primary outcomes were changes in posterior spatial dimension (PSD), superior spatial dimension, and medial spatial dimension assessed by cone-beam computed tomography preoperatively, immediately after surgery, and at 1-year follow-up. Covariates included sex, age, and amount of mandibular advancement. Estimations of independent effects of primary predictors on outcome variables were made by applying generalized estimation equation models. The value of statistical significance was P<.05. The study sample included 88 participants. The BSSO samples included 39 patients, and the BMO group included 22 patients; the control group comprised 27 subjects. The average age was 31.2years; the majority were female (61.4%). Adjusted generalized estimation equation models yielded a significant time interaction between BSSO and spatial dimensions over time (PSD, P<.001). Key predictors of spatial dimension changes were the baseline posterior (PSD, P<.001) and the central condylar position (PSD, P<.001). This controlled study, for the first time, provides scientific evidence on the effects of surgical intervention type and baseline condylar position on spatial dimension changes in the TMJ. It shows a more favorable outcome in long-term spatial dimension changes for patients treated by a BMO procedure.

Quantitative assessment of condylar bone resorption using fused CBCT images: differentiating and diagnosing three distinct groups based on volume and thickness decrease.

To investigate the accuracy of fused CBCT images in diagnosing three distinct groups of bone changes characterized by volume and thickness decrease in patients with temporomandibular joint osteoarthrosis (TMJ OA) during follow-up. In this retrospective study, 109 patients (176 TMJs) with TMJ OA were included. Two consecutive CBCT images for the same patient were registered and fused. Then, three image sets were established: without fusion, fused 2D image, and fused 3D image. Three residents randomly and independently evaluated whether there was condylar resorption with the three image sets respectively. The samples diagnosed as condylar resorption by the expert panel were divided into three subgroups according to the volume and thickness decrease calculated after segmentation. The inter- and intraobserver agreement, receiver operating characteristic (ROC), and area under the curve (AUC) evaluated the diagnostic capability for different subgroups. For the volume decrease more than 50 mm3 and thickness decrease more than 1 mm groups, the AUC values for fused image sets were higher than those without fusion (p < 0.01). For the volume decrease within 50 mm3 and thickness decrease within 1 mm groups, the AUC values for fused 2D image sets were higher than the image sets without fusion (p < 0.05), but there was no significant difference between the fused 3D image sets and the image sets without fusion (p = 0.48 for volume decrease, p = 0.37 for thickness decrease). The fused images can improve the diagnostic accuracy and repeatability for the samples with at least 50 mm3 volume decrease or 1 mm thickness decrease compared with the image groups without fusion.

Biomechanical Evaluation of a Standard Temporomandibular Joint Prosthesis and Screw Arrangement Optimization: A Finite Element Analysis.

Artificial total joint replacement is an important method of temporomandibular joint (TMJ) reconstruction, which has been advocated for TMJ osteoarthrosis, ankylosis, tumors, and other diseases. We designed one type of standard TMJ prosthesis fit for Chinese patients. This study aimed to explore the biomechanical behavior of the standard TMJ prosthesis using finite element analysis and selects an optimal screw arrangement scheme for clinical application. A female volunteer was recruited for a maxillofacial computed tomography scan, then the Hypermesh software was used to establish a finite element model of a mandibular condyle defect repaired with an artificial TMJ prosthesis. An advanced universal finite element program software was used to calculate the stress and deformation under a simulated maximum bite force loading. Also, the forces of screws under different numbers and arrangements were analyzed. Meanwhile, we designed an experiment to verify the calculation model. The average maximum stress of the fossa component of the standard prosthesis model was 19.25MPa. The average maximum stress of the condyle component was 82.58MPa, mainly concentrated near the top row hole. The fossa component should be fixed with at least 3 screws, and the optimal number of screws was 4. The condyle component should be fixed with at least 4 screws, and its optimal number was 6. The best scheme of screw arrangement was determined. The results of the verification experiment showed that the analysis was reliable. The stress distribution of the standard TMJ prosthesis is uniform, meanwhile, the number and arrangement of the screws significantly affect the contact force of the screws.

Imaging study on the relationship between anterior and posterior occlusal planes and temporomandibular osteoarthrosis.

The aim of this study was to compare the anterior and posterior occlusal plane characteristics of patients with different temporomandibular joint osseous statuses. A total of 306 patients with initial cone beam CT (CBCT) and cephalograms were included. They were divided into three groups on the basis of their temporomandibular joint osseous status: bilateral normal (BN) group, indeterminate for osteoarthrosis (I) group, and osteoarthrosis (OA) group. The anterior and posterior occlusal planes (AOP and POP) of the different groups were compared. Then, the regression equation was established after adjusting for confounding factors, and a correlation analysis between the occlusion planes and other parameters was performed. SNA, SNB, FMA, SN-MP, Ar-Go, and S-Go were correlated with the occlusal planes. Relative to the BN and I groups, the FH-OP of the OA group increased by 1.67° on the average, FH-POP increased by 1.42° on the average, and FH-AOP increased by 2.05° on the average. The occlusal planes were steeper in the patients with temporomandibular osteoarthrosis than in the patients without it, and the mandible rotated downward and backward. The height of the mandibular ramus, the mandibular body length, and the posterior face height were small. In clinical practice, attention should be given to the potential risk of temporomandibular joint osteoarthrosis in such patients. In addition, SNB, FMA, SN-MP, Ar-Go, S-Go, and occlusal planes had moderate correlations.

Ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix improves rabbit temporomandibular joint osteoarthrosis

ABSTRACT Objective: To investigate whether and how ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix can improve rabbit temporomandibular joint osteoarthrosis. Method: Isolate and culture adipose stem cells, measure the activity of differentiated chondrocytes by MTT assay and expression of type II collagen in these cells by immunohistochemistry, in order to evaluate the effect of ginsenoside Rg1 on adipose stem cell proliferation and differentiation into chondrocytes.32 New Zealand white rabbits were randomly divided into four groups: blank group, model group, control group and experimental group, 8 in each group. Osteoarthritis model was established by intra-articular injection of papain. Two weeks after successful model building, medication was given for the rabbits in control group and experimental group. 0.6 mL ginsenoside Rg1/ ADSCs suspension was injected into superior joint space for the rabbits in control group, once a week; 0.6 mL ginsenoside Rg1/ ADSCs complex was injected for the rabbits in experimental group, once a week. Results: Ginsenoside Rg1 can promote ADSCs-derived chondrocytes’ activity and expression of type II collagen. Scanning electron microscopy histology images showed cartilage lesions of the experimental group was significantly improved in comparison with control group. Conclusion: Ginsenoside Rg1 can promote ADSCs differentiate into chondrocytes, and Ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix can significantly improve rabbit temporomandibular joint osteoarthrosis.

Analysis of the Curative Effect of Temporomandibular Joint Disc Release and Fixation Combined with Chitosan Injection in the Treatment of Temporomandibular Joint Osteoarthrosis

Temporomandibular joint osteoarthritis (TMJ-OA) is common in clinic. The purpose of this study was to evaluate the efficacy of disc release, fixation and chitosan injection in the treatment of TMJ-OA. From March 2021 to March 2022, 32 patients who underwent the unilateral reduction and fixation of temporomandibular joint disc release were retrospectively studied. All patients were diagnosed with TMJ-OA and were treated with chitosan injection. This group of patients was analyzed by the visual analog scale (VAS) for pain and improvement of maximum comfortable mouth opening before treatment and 6 months after treatment. A paired t-test was used to evaluate the treatment effect, and p < 0.05 indicated that the difference was statistically significant. All 32 patients were successfully treated by surgery and chitosan injection in the second week after operation. The duration of disease in this group ranged from 1 to 10 months, with an average of 5.7 months. After 6 months of follow up, 30 patients were satisfied with the treatment and two were unsatisfied. The difference in the treatment effect was found to be statistically significant (p < 0.05). Temporomandibular joint disc release and fixation combined with chitosan injection is effective in the treatment of TMJ-OA.

Association of temporomandibular joint osteoarthrosis with dentoskeletal morphology in males: A cone-beam computed tomography and cephalometric analysis.

The objective of the study was to assess the differences in dentoskeletal morphology in males with and without temporomandibular joint osteoarthrosis (TMJOA). Three hundred seventy-one male participants seeking orthodontic treatment were enrolled in this cross-sectional study. Each participant's osseous status was evaluated using cone-beam computed tomography (CBCT) and classified into normal (N=104), indeterminate for TMJOA (N=110) and TMJOA (N=157) groups. The dentoskeletal characteristics were evaluated using cephalograms. Stratified analysis was performed based on age and skeletal pattern. Descriptive statistics and one-way analysis of variance were performed to investigate dentoskeletal differences among groups. P < .05 was considered statistically significant. The differences in posterior cranial base length, FMA, MP-OP, anterior facial height, articular angle, ramus height and L1-MP were statistically significant. After stratification by age, the differences in FMA, maxillomandibular angle, posterior facial height, facial height ratio, gonial angle and mandibular body length were statistically significant in adults. No statistical difference except for articular angle was observed in adolescents. After stratification by skeletal pattern, statistical differences were mainly apparent in skeletal Class II adults. Males with TMJOA showed a posteriorly positioned and backward-rotated mandible, especially in skeletal Class II adults. Compared with women, the craniofacial morphology of men is less affected by TMJOA. The association between TMJOA and craniofacial morphology also varied across different age groups and skeletal patterns. Prospective studies are required to clarify the cause-effect relationship between TMJOA and craniofacial morphology in males.

Imaging observation and analysis of condylar osteosclerosis in temporomandibular joint osteoarthrosis

Objective: To observe the different imaging manifestations of condylar sclerosis in temporomandibular joint osteoarthrosis and explore the imaging significance of condylar sclerosis. Methods: From January 2018 to December 2020, 50 patients with temporomandibular joint condylar sclerosis were examined by cone-beam CT (CBCT) and underwent spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 15 males and 35 females aged from 16 to 65 years with age of (42.7±14.5) years. The imaging manifestations of CBCT, spiral CT, MRI and radionuclide bone imaging, joint disc displacement and abnormal bone metabolism of condylar sclerosis were analyzed. And the area of condylar sclerosis was graded according to the image of CBCT. Results: A total of 50 patients were included, including 38 unilateral condylar sclerosis, 12 patients with bilateral condylar sclerosis, the total condylar sclerosis were 66. There was no significant difference between the detection rate of further spiral CT (95.5%, 63/66) and CBCT (100.0%, 66/66) (corrected χ²=1.36,P=0.244). The area of condylar sclerosis was (35.5±4.5) mm2, ranged from 1 to 100 mm2. In addition, spiral CT showed more clearly condylar sclerosis than CBCT. Sclerosis can occur in all parts of condyle, mainly in the upper middle region (68.2%,45/66) in coronal position and in the upper front region (71.2%,47/66) in sagittal position. Fifty-seven condylar sclerosis were detected by MRI, including 4(4/19) condylar sclerosis less than 4 mm2. There was significant difference in the displacement of temporomandibular joint disc between the sclerotic side and the non sclerotic side (χ²=10.09, P=0.006). MRI display the condylar sclerosis showed low signal (56/62), followed by high signal (5/62) and medium signal (1/62). Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism, 34 had abnormal bone metabolism, and 21 patients had concentrated on the non-sclerotic side. Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism and 34 had abnormal bone metabolism. Conclusions: Spiral CT is more accurate than CBCT in terms of condyle sclerosis through different imaging analysis, and the detection rate of both is higher than MRI. Most of condylar sclerosis showed different degrees of low signal on MRI. The condylar sclerosis side is usually manifested by abnormal bone metabolism.

Diagnostic accuracy of fused CBCT images in the evaluation of temporomandibular joint condylar bone resorption.

To evaluate the diagnostic accuracy of fused CBCT images for patients with condylar bone resorption of temporomandibular joint (TMJ) osteoarthrosis. Forty-two TMJs from twenty-one patients were included. Bone resorption of condyles evaluated by three experts was used as the reference standard. Three oral and maxillofacial radiology residents evaluated the resorption of condyles with a five-point scale for the four sets of images (two consecutive CBCT images without fusion, fused 2D cross-sectional images, fused 3D images, andcombining fused 2D cross-sectional images and fused 3D images) randomly and independently. Each set of images was evaluated at least 1week apart, and a second evaluation was performed 4weeks later. Intraclass correlation coefficients were calculated to assess the intra- and inter-observer agreement. The areas under the ROC curves (AUCs) were compared among the four image sets using the Z test. Twenty-four TMJs were determined as condylar bone resorption, and eighteen were determined as no obvious change. The average AUC values from the three observers for the three fused image sets (0.94, 0.93, 0.93) were significantly higher than the image set without fusion (p < 0.01). The intra- and inter-observer agreement on the three fused image sets (0.70-0.89, 0.91-0.92) was higher than the image set without fusion (0.37-0.63, 0.75). Fused CBCT images of TMJ osteoarthrosis patients can intuitively display the condylar bone resorption and significantly improve the diagnostic accuracy. Fused CBCT images can help clinicians intuitively observe bone changes of the condyle in TMJ osteoarthrosis patients.

Construction and pathological characterization of 3 animal models of temporomandibular joint degenerative joint disease in mice

Objective: To explore the pathological characteristics of three mice models of temporomandibular joint degenerative joint disease (TMJDJD), including osteoarthritis and osteoarthrosis, and to provide references for animal experimental study regarding the pathological mechanism of osteoarthritis and osteoarthrosis. Methods: A total of 54 8-week-old male C57BL/6 mice were selected to construct three TMJDJD animal models, including bilateral temporomandibular joint (TMJ) Freund's complete adjuvant (FCA) injection model, bilateral TMJ monosodium iodoacetate (MIA) injection model, and right TMJ discectomy model. FCA injection model (15 mice) was divided into saline injection group, FCA injection group-1 week, FCA injection group-2 week, FCA injection group-4 week and FCA injection group-6 week, 3 mice were used at each time point, with a total of 6 TMJs on both sides. MIA injection model (15 mice) was separated into saline injection group, MIA injection group-1 week, MIA injection group-2 week, MIA injection group-4 week and MIA injection group-6 week, 3 mice were used at each time point, with a total of 6 TMJs on both sides. TMJ discectomy model (24 mice) was split into control group, discectomy group-2 week group, discectomy group-4 week and discectomy group-6 week, six mice were used at each time point, with a total of six right TMJs. General pictures of the bilateral joints area of mice were collected 1 day after drug injection, and stereoscopic images of condylar tissues were collected 4 weeks after microsurgery for discectomy. Mouse TMJ tissue sections from each time point were stained with HE and toluidine blue, respectively, synovial tissues were scored for synovial inflammation, and the percentage of proteoglycan in condylar cartilage was quantitatively analyzed. Results: One day after intra-articular FCA or MIA injection, the width of bilateral TMJ were significantly increased in FCA injection groups [(24.60±0.46) mm] compared with the saline injection group [(21.63±0.52) mm] (t=4.25, P<0.013), the width of bilateral TMJ in MIA injection groups [(24.50±0.62) mm] were also significantly higher than that in saline injection group [(21.40±0.52) mm] (t=3.82, P=0.019). The synovitis scores in FCA injection groups 1, 2, 4, 6 weeks after FCA injection were significantly higher than that of the saline injection group (F=18.09, P<0.001), with the proteoglycan of condylar cartilage increased firstly and then decreased compared with the saline injection group (F=21.59, P<0.001). Condylar cartilage proteoglycan loss in different degrees were observed 1, 2, 4 and 6 weeks after MIA injection (F=13.59, P<0.001), and synovitis scores were increased at different degrees compared with saline injection group (F=14.79, P<0.001). The morphology of condylar cartilage in discectomy groups mice were severely damaged, synovial tissues showed dense connective tissue lesions at 2, 4 and 6 weeks postoperatively, condylar cartilage tissues showed a time-dependent loss of proteoglycan compared with the control group (F=40.62, P<0.001). Conclusions: Intra-articular FCA injection establishes a mouse model of TMJ osteoarthritis with severe synovial inflammation. Intra-articular MIA injection constructs a mouse model of typical TMJ osteoarthritis. Discectomy establishes a mouse TMJ osteoarthrosis model with severe condylar cartilage destruction.

Natural course of severe temporomandibular joint osteoarthrosis evaluated by a novel condylar remodelling scoring system and quantitative volumetric analysis

Temporomandibular joint osteoarthrosis (TMJ-OA) frequently causes mild, moderate, or severe condylar morphological changes. A novel condylar remodelling scoring system (CRSS) based on three-dimensional cone beam computed tomography images is proposed, which is used to grade condylar morphological changes. In the CRSS, the condyle is divided into 10 regions by 11 reference points. For each increase in the number of regions involved in TMJ-OA, one point is subtracted from the full score of 10. The intra-class correlation coefficients for intra- and inter-observer agreement (range 0.656–0.898 and 0.841–0.906, respectively) indicated that the CRSS had good reliability. Cephalometric analysis showed that the condyles with severe morphological changes were prone to present with a retrognathic and clockwise rotating mandible, shorter ramus height, reduced mandibular length, larger mandibular angle, and maxillary retrusion. Qualitative CRSS evaluation and quantitative volumetric analysis were performed to evaluate the stability of severe TMJ-OA in its natural course (343 condyles). The continuous cortex group showed no remarkable changes with an average follow-up of 2 years. In the discontinuous cortex group, most (74.4%) converted into a continuous cortex during follow-up (mean 2 years).

Correlation between temporomandibular joint osteoarthrosis and coronoid process

Objective: To investigate the morphological characteristics of coracoid process in different stages of temporomandibular joint osteoarthrosis (TMJOA), and to provide theoretical data for clinical and anatomic study. Methods: A total of 290 patients who were diagnosed with TMJOA in the Department of Temporomandibular Joint, Kunming Medical University School and Hospital of Stomatology from January 2015 to February 2021 were collected, including 69 males and 221 females, with an average age of 35.1±13.7 years (16-69 years old), 64 cases of unilateral lesions (64 sides), and 226 cases of bilateral lesions (452 sides). According to the TMJOA X-ray staging standard put forward by Ma Xuchen in 2005, the affected joints were divided into stage I (227 sides), stage Ⅱ (38 sides), stage Ⅲ (164 sides) and stage Ⅳ (87 sides). Twenty-six patients without clinical and imaging manifestations of temporomandibular disorders in the Department of Radiology, Kunming Medical University School and Hospital of Stomatology from October 2020 to June 2021 were selected as the control group, including 8 males and 18 females. The average age was (34.3±13.9) years (17-60 years). The dicom data of each group were imported into SimplantPro11.04 software to measure the height of coracoid process, anteversion angle and the ratio of coracoid vertex to mandibular corner to condylar vertex to mandibular angle. R 3.6.1 was used to analyze the difference of the morphological characteristics of coracoid process between in the affected side of TMJOA and in the both sides of the control group, in the healthy side and the affected side of unilateral patients and in different stages of TMJOA. Results: The height of the coracoid process [(16.26±2.81 mm)], the ratio of the coracoid process vertex-mandibular angle point and the condyle vertex-mandibular angle point distance [0.96(0.92,1.01)] on the affected side of TMJOA were significantly higher than those in the control group [(15.31±3.03)mm;0.95(0.89、0.99)] (t=2.18, P=0.033; t=2.87, P=0.004). There was no significant difference between the ante-version angle and the control group (t=-1.37, P=0.176). The ratio of the distance between the apex of the coracoid process and the apex of the mandibular angle to the apex of the condyle and the angle of the mandible in the affected side of unilateral patients was significantly greater than that in the healthy side (t=-3.46, P=0.001). There was no significant difference in coracoid height, coracoid anteversion angle and the healthy side (t=-1.85, P=0.069; t=-0.06, P=0.955) in different periods. The intra-group analysis showed that there was no significant difference in the height of the coracoid process in different stages (F=0.37, P=0.774). There was no significant difference in the ante-version angle of the coracoid process: stage I, stage Ⅱ, and stage Ⅲ (P>0.008), but all were significantly smaller than stage Ⅳ (PⅠ-Ⅳ<0.001, PⅡ-Ⅳ=0.009, PⅢ-Ⅳ<0.001). The ratio of the distance between coracoid apex-mandibular angle and condyle apex-mandibular angle: there was no significant difference in stage I, stage Ⅱ, and stage Ⅲ (P>0.008), and stage I and stage Ⅲ were significantly smaller than stage Ⅳ (P<0.001). Conclusions: The coracoid height and the ratio of the coracoid apex-mandibular angle to the condyle apex-mandibular angle distance on the TMJOA side were significantly greater than those without temporomandibular joint disorders. The bone deposition was mainly concentrated in the upper and posterior part of the condyle. TMJOA had a certain correlation with the height of the coracoid process.

Temporomandibular joint osteoarthritis: recognizing and challenging

Temporomandibular joint osteoarthritis is an ancient and challenging common disease in clinic. The challenge is clarifying the relationship among temporomandibular joint osteoarthritis, temporomandibular joint osteoarthrosis and temporomandibular disorders, understanding mutual influence among all bony structures' pathological lesions in the joint and exploring pathogenesis, making early diagnosis and accurate diagnosis, and giving effective and standard treatment.

The role of elastic bands (kinesiotapes) in complex therapy of patients with temporomandibular joint osteoarthrosis

Introduction. Temporomandibular joint (TMJ) arthrosis is a chronic disease, characterized by dystrophic and degenerative changes in TMJ with aseptic inflammatory process. The prevelence of TMJ arthrosis in patients with a history of other TMJ disorders varies between 32-39 % of cases. Complex treatment of TMJ arthrosis includes pharmacotherapy, physiotherapy, exercise therapy for TMJ and massage of the masticatory muscles, manual therapy, prosthodontics, but these treatment methods are not always lead to a desired result.The aim of the study is to improve the traditional treament method of patients suffering from TMJ arthrosis by using elastic tapes (kinesiotapes).Materials and methods. 68 patients were examined at the «Galaxy» Beauty Institute Clinic (St. Petersburg) and FSBEI HE SamSMU MOH Russia (Samara). Comparison group of patients was prescribed pharmacotherapy, exercise therapy for TMJ and massage of masticatory muscles, while for the main group of patients the same therapy was enhanced by elastic bands. The effectiveness of therapy was evaluated using a visual-analog pain scale (VAS), mouth opening width and electromyography of the masticatory muscles.Results. Noticeable positive effect in the main group of patients was observed on the 21th day of treatment. By this time patients noticed significant decrease in pain intensity from 8,77±0,8 to 5,19±0,5 (Z1-4=-5,88; p1-4=0,0015) points as well as increase in mouth opening width from 21-23 to 33-35 mm. Similar changes in the comparison group of patients were achieved only by the beginning of fifth week of treatment (Z1-6=-5,58; p1-6=0,0015). The range of mouth opening width increased from 21-23 to 27-29 mm. Amplitude of masticatory muscles biopotentials in maximum intercuspation in patients of the main group almost approached to the normal results by the beginning of the fourth week. In patients of the comparison group the amplitude of masticatory muscles biopotentials remained reduced even by the end of observations (42 day of the study).Conclusion. Thus, the combination of elastic bands applications with conventional treatment methods of TMJ arthrosis greatly increases the effectiveness of therapy and allows to relief pain and normalize bioelectric activity of masticatory muscles in a relatively short time. Due to the simplicity of elastic bands application it is possible to teach patients the technique of self-applying bands and recommend to use them as a prevention of relapse of TMJ arthrosis.

Hyoid Bone Position in Patients with and without Temporomandibular Joint Osteoarthrosis: A Cone-Beam Computed Tomography and Cephalometric Analysis.

Objective To assess the differences in hyoid bone position in patients with and without temporomandibular joint osteoarthrosis (TMJOA). Methods The present cross-sectional study was conducted in 427 participants whose osseous status was evaluated using cone-beam computed tomography and classified into normal, indeterminate osteoarthrosis (OA), and OA. The hyoid bone position and craniofacial characteristics were evaluated using cephalograms. Patients were divided into the normal group (N = 89), indeterminate OA group (N = 182), and OA group (N = 156). Descriptive statistics, one-way analysis of variance, and age- and sex-based stratified analyses were performed. P < 0.05 was considered statistically significant. Results The differences in Hy to MP, Hy-RGn, Hy to C3-RGn, C3-RGn, and Go-Hy-Me among the three groups were statistically significant. The differences in the Frankfort-mandibular plane angle, saddle angle, articular angle, gonial angle, ramus height, and posterior facial height were statistically significant. After adjusting age and sex, the Hy-RGn and C3-RGn in the normal group were significantly greater than the OA group. No statistical differences were observed in the hyoid measurements in the stratified analyses in males or subjects less than 18 years old. The differences in Hy to MP, Hy to C3-RGn, and Go-Hy-Me in female patients among the three groups were statistically significant. The differences in Hy to SN, Hy to FH, Hy to PP, Hy to MP, Hy-RGn, Hy-C3, Hy to C3-RGn, Go-Hy-Me, Hy-S, and C3-Hy-S in adults were statistically significant. Conclusion The differences in the hyoid bone position, mainly relative to the mandible, were statistically significant in patients with or without TMJOA. The difference pattern varied among different age and sex groups. Clinical evaluation of the hyoid position must consider the age and sex of patients. Longitudinal studies are required to clarify the causal relationship between TMJOA and hyoid bone position.

Diagnostic significance of magnetic resonance imaging in distinguishing temporomandibular disorders: a retrospective chart review

BackgroundThis study was to evaluate the diagnostic significance of Magnetic Resonance Imaging (MRI) in distinguishing temporomandibular disorders (TMD).MethodsA total of 684 patients with TMD were included in the study. Diagnosis for TMD was conducted according to the international criteria. Two professional radiologists were selected for professional training, and the Kappa values were compared for the diagnosis results to determine the consistency of the diagnosis. Then MRI images of these 684 patients were analyzed and the diagnosis results were obtained.ResultsMRI can be used for the diagnosis of TMD. There were significantly more females (518 cases) than males (166 cases) with TMD; Disc displacement with/without reduction is more common in the youth group, with the majority aged 20–30 years. The highest incidence of temporomandibular joint osteoarthrosis is in the 60-year-old age group, followed by the 70-year-old age group.ConclusionsBilateral temporomandibular joint MRI can clearly show their changes; there are significantly more female with TMD than male; osteoarthritis has a significant correlation with age.

A comparative study on the radiographs of spiral CT and cone-beam CT in temporomandibular joint osteoarthrosis

Objective: To observe and compare the radiographs of spiral CT and cone-beam CT (CBCT) in the imaging of temporomandibular joint osteoarthrosis (TMJOA) and to explore the difference between CBCT and spiral CT in detection accuracy so as to provide references for clinical diagnosis and treatment. Methods: A total of 52 patients with TMJOA diagnosed in the Department of Oral and Maxillofacial Surgery, General Hospital of Chinese PLA, from January 2018 to December 2019 were selected. There were 10 males and 42 females, with an average age of 38.6 years (21-70 years). All patients underwent spiral CT and CBCT examinations. Two oral radiologists and two oral and maxillofacial surgeons measured and evaluated the joint spaces and condylar bone lesions of each side of temporomandibular joint. According to the presence or absence of osteoarthrosis, the patients were divided into osteoarthrosis group (92 sides) and non osteoarthrosis group (12 sides). The mean size of joint spaces and the detection rate of lesions were compared between the two groups. SPSS 20.0 was used to analyze the data. Results: There was no significant difference between the measurements of joint space size and joint position in the spiral CT group and the CBCT group (P>0.05). The mean size of the anterior space and the ratio of the posterior condyle in the osteoarthrosis side were larger than that in the normal side. The LR index was smaller in the osteoarthrosis side than that in the normal side indicating that the position of the posterior condyle in the osteoarthrosis side was deviated. However, the difference was not statistically significant (P>0.05). Both spiral CT and CBCT showed good consistency in displaying condylar osteopathy. The most common types of condylar osteopathy was surface defect. The detection rates of defects by spiral CT were surface erosion (85.6%, 89/104), articular surface flattening and shortening (82.7%, 86/104), subcortical sclerosis (40.4%, 42/104), osteophyte (40.4%, 42/104) and subcortical cyst (11.5%, 12/104) respectively. The detection rates of defects by CBCT were surface erosion (88.5%, 92/104), articular surface flattening and shortening (86.5%, 90/104), subcortical sclerosis (35.6%, 37/104), osteophyte (41.3%, 43/104) and subcortical cyst (11.5%, 12/104). There was no statistical difference between the two groups (P>0.05), respectively. Conclusions: Both spiral CT and CBCT showed good accuracies in displaying the osteopathy of TMJOA and the sizes of the joint spaces measured by spiral CT and CBCT were basically the same. Both spiral CT and CBCT could be used as a routine diagnostic method for TMJOA.

Temporomandibular Joint Osteoarthrosis: A Review of Clinical Aspects and Management.

The symptoms of TMJ Osteoarthrosis/Osteoarthritis(TMJ OA) are characteristic and in most cases specific to the disorder. There is, however, an overlap of symptoms with other TMDs.Treatment of TMJ OA is generally directed towards management of the symptoms as the temporomandibular joint does retain the capacity throughout life to repair and remodel. Non-conservative and invasive treatment is only rarely necessary.It should be remembered that the mandibular condyle retains the capacity to repair and remodel throughout life and patients should be encouraged to bear this in mind. Conservative measures are usually sufficient to treat symptoms and a period of time should be allowed to elapse before undertaking a more aggressive treatment plan, which, in the overwhelming majority of patients, will not be necessary. This disorder should be approached on the terms of 'a quality of life issue' and treatment should be directed towards patient needs.

Morphological and histopathological evaluation of temporomandibular joint osteoarthrosis induced by perforation of articular disc in rats

Objective: To establish the animal model of temporomandibular joint osteoarthrosis (TMJOA) in rats induced by perforation of articular disc and evaluate the morphological characteristics and histopathological changes of the condyle of temporomandibular joint (TMJ). Methods: Eight male SD rats, purchased from Chongqing Medical University, were marked from No. 1 to No. 8 according to a random number table. The eight numbered rats were then arranged according to their sizes from large to small. The first four rats were divided into the one-week group, while the last four were divided into the four-week group. In order to simulate a TMJ disc perforation, an oblique incision was created along the zygomatic arch of the left side (the model side) making the TMJ superior joint space exposed. The left disc was pulled out and artificially perforated by a dental round bur with 1.5 mm diameter at the postmedian part of TMJ disc. The disc of the right side (the control side) was kept intact. The rats were randomly euthanized respectively at 1 week or 4 weeks (n=4 for each time point) for further study. Morphological observation and imaging examination were used to assess the degree of articular cartilage degradation and the loss of subchondral bone. Immunohistochemicalstaining (IHC), safranin O and fast green staining, tartrate-resistant acid phosphatase (TRAP) staining and haematoxylin staining were performed to evaluate the histopathological changes of condylar cartilage. Results: In the morphological observation, significant redness and swelling were observed on the model side of the 1-week-group and the typical beak-like change of osteoarthropathy was observed on the model side of the 4-week-group. The heights of condylar process on the model sides in the 1-week-group and 4-week-group [(2.73±0.14) and (2.49±0.25) cm, respectively] were significantly lower than that in the control side [(3.30±0.09) and (3.30±0.12) cm, respectively] (P<0.01). Imaging examination showed obvious damage in trabecular microstructure on the model side of the 4-week-group. Safranin O and fast green staining showed that the amounts of proteoglycan on the model sides of the 1-week-group and the 4-week-group were significantly lower than that on the control sides (P<0.01). TRAP staining showed that the numbers of osteoclasts on the model side of the 1-week-group and the 4-week-group was significantly higher than that on the control sides (P<0.01). IHC staining and Haematoxylin staining showed that the mean optical densities of collagen on the model side of the 1-week-group and the 4-week-group was significantly reduced compared with that on the control sides (P<0.01), while the mean optical densities of matrix metalloproteinase increased significantly (P<0.01). Conclusions: After making a articular disc perforation, the condylar cartilage on the model side presented typical TMJOA pathological changes.

Yohimbine Ameliorates Temporomandibular Joint Chondrocyte Inflammation with Suppression of NF-κB Pathway.

Local joint inflammation plays an important role in the pathogenesis of temporomandibular joint (TMJ) osteoarthrosis (TMJOA). Yohimbine, an alpha-2 adrenergic receptor antagonist, possesses anti-inflammatory properties; however, the ability of Yohimbine to protect against TMJOA-associated chondrocyte inflammation remains unclear. We conducted in vitro and in vivo analyses to investigate whether Yohimbine could ameliorate TMJOA-induced chondrocyte inflammation and to elucidate the mechanisms involved. Chondrocytes of TMJOA mice were stimulated with interleukin (IL)-1β or noradrenaline (NE), and the resulting production of inflammation-related factors was evaluated in the presence or absence of Yohimbine. Furthermore, two TMJOA mouse models were treated with Yohimbine and the therapeutic effect was quantified. NE (10-6 M) triggered inflammatory cytokine secretion by TMJ chondrocytes, and Yohimbine suppressed IL-1β- or NE-induced IL-6 upregulation in TMJ chondrocytes with the nuclear factor (NF)-κB pathway inhibition. Yohimbine also ameliorated cartilage destruction in the TMJOA models. Interestingly, αmpT, a tyrosine hydroxylase inhibitor, reversed the effects of Yohimbine by activating the NF-κB pathway. Collectively, these findings show that Yohimbine ameliorated TMJ chondrocyte inflammation and the suppression of NF-κB pathway contributes to this effect.