Temporomandibular Joint Arthritis Research Articles

Phosphotungstic acid-enhanced micro-computed tomography and RNA sequencing provide a new perspective on temporomandibular joint arthritis induced by complete Freund's adjuvant and collagen-induced arthritis in rat models

Background/PurposeTemporomandibular joint (TMJ) arthritis causes inflammation and degradation of the mandibular condylar cartilage and subchondral bone. Complete Freund's adjuvant (CFA) and collagen-induced arthritis (CIA) are models for studying TMJ arthritis. While micro-computed tomography (micro-CT) is crucial for three-dimensional (3D) bone analysis, it has limitations in imaging nonmineralized tissues. Phosphotungstic acid (PTA) enhances soft tissue contrast. However, research on the 3D imaging of mandibular condylar cartilage and the molecular mechanisms of CFA- and CIA-induced arthritis remains unclear. This study aimed to investigate the bone and PTA-stained cartilage in the mandibular condyle using 3D reconstruction and explore the characteristics of enriched gene ontology terms underlying CFA- and CIA-induced TMJ arthritis in rat models. Materials and methodsRat mandibular condyles were collected from control, CFA, and CIA groups. Live micro-CT created 3D bone structures, and PTA-enhanced micro-CT constructed 3D mandibular condylar cartilage. Gene ontology enrichment analysis identified enriched gene ontology terms from differentially expressed genes through RNA sequencing. ResultsMajor deformities in cartilage volume and bone morphology were observed in the arthritis-induced groups. The CIA group exhibited significant correlations between cartilage volume and bone parameters changes. Gene ontology enrichment analysis indicated fewer terms with upregulated differentially expressed genes related to inflammation and immune response in the CIA group than in the CFA group. ConclusionThis study reveals distinct responses between CFA- and CIA-induced TMJ arthritis models. The CIA group exhibited strong correlations between cartilage volume and bone parameter changes and had less pronounced inflammation and immune response than the CFA group.

Temporomandibular joint rehabilitative approaches for children and adolescents affected by juvenile idiopathic arthritis: A systematic review.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease of childhood, and temporomandibular joints (TMJs) are involved in 39%-78% of patients. The aim of this systematic review was to assess the effectiveness of conservative approaches in improving TMJ arthritis in children and adolescents affected by JIA. PubMed, Scopus, and Web of Science were systematically searched from the inception until February 25, 2024, to identify observational studies presenting participants with a diagnosis of JIA affecting the TMJ, rehabilitative approaches for TMJ arthritis as interventions, and clinical or radiological assessment of TMJ arthritis as outcome. Of 478 papers suitable for title/abstract screening, 13 studies were included. The studies evaluated the effectiveness of intra-articular (IA) corticosteroid (CS) injections, IA infliximab injections, arthrocentesis alone or in combination with IACS injections, occlusal splint, functional appliance, and physiotherapy. The effectiveness of IACS injections was shown in eight studies. IA infliximab injections did not appear to significantly improve TMJ arthritis. Results of this systematic review suggested that conservative treatments, especially IACS injections, might be effective in improving TMJ arthritis in patients affected by JIA. Further studies with a higher level of evidence and more representative samples should be conducted.

The Effect of Low-Intensity Pulsed Ultrasound on Temporomandibular Joint Arthritis in Juvenile Rats.

Juvenile idiopathic arthritis is an inflammatory disease that can affect the temporomandibular joint (TMJ) and lower jaw growth. Better treatment options are needed, so this study investigated the effect of low-intensity pulsed ultrasound (LIPUS) on TMJ arthritis. Seventy-two 3-week-old male Wistar rats were invivo microcomputed tomography (micro-CT) scanned and divided into eight groups (n = 9). These groups were Group 1-TMJ arthritis and immediate LIPUS treatment (20 min/day, 4 weeks); Group 2-immediate LIPUS treatment and no TMJ arthritis; Group 3-TMJ arthritis and no LIPUS; Group 4-no TMJ arthritis and no LIPUS; Group 5-TMJ arthritis and LIPUS treatment with a delayed start by 4 weeks; Group 6-Delayed LIPUS and no TMJ arthritis; Group 7-TMJ arthritis and no (delayed) LIPUS; and Group 8-no TMJ arthritis and no (delayed) LIPUS. Ex vivo micro-CT scanning was completed, and samples were prepared for tissue analysis. Synovitis was observed in the TMJ arthritis (collagen-induced arthritis [CIA]) groups, but the severity appeared greater in the groups without LIPUS treatment. Fibrocartilage and hypertrophic cell layer thicknesses in the CIA group without LIPUS treatment were significantly greater (p < 0.05). Proteoglycan staining appeared greater in the LIPUS groups. Immediate LIPUS treatment increased the expression of type II collagen, type X collagen, and transforming growth factor-beta 1 (TGF-β1) immunostaining, and CIA (no LIPUS) increased MMP-13, vascular endothelial growth factor, and interleukin-1 beta (IL-1β) immunostaining. LIPUS treatment prevented growth disturbances observed in the CIA groups (no LIPUS) (p < 0.005). Our results have contributed to the understanding of the uses and limitations of the CIA juvenile rat model and have demonstrated the effects of LIPUS on the TMJ and mandibular growth. This information will help in designing future studies for investigating LIPUS and TMJ arthritis, leading to the development of new treatment options for children with juvenile arthritis in their TMJs.

Degenerative Temporomandibular Disorders: An Assessment of Bone Trabecular Structure Using Fractal Analysis in Digital Panoramic Radiographs.

Introduction Fractal analysis has proved to be a salient tool to quantitatively assess the qualitative changes in the bone trabeculae of patients with hyperparathyroidism, osteoporosis, and various temporomandibular disorders, including osteoarthritis (OA) and rheumatoid arthritis of temporomandibular joint (TMJ), in several previous studies. The purpose of this study was to use fractal analysis to assess alterations in the trabecular pattern of the mandibular condyle in patients with degenerative temporomandibular disorders. Materials and methods This study comprised 98 subjects with 49 subjects in the study group and 49 subjects in the control group, aged 18-50 years. Age and sex in the control group were matched to those in the case group. The subjects were assessed clinically with the Diagnostic Criteria for Temporomandibular Disorders. Digital panoramic X-ray equipment with set parameters of 70 kvp, 8 mA, and 16-second exposure duration was used to take panoramic radiographs. Fractal analysis was done and the calculated fractal dimension value was obtained usingImageJ version 1.48 software (National Institutes of Health, Bethesda, MD). The same observer used Muir and Goss's method to rate the total degenerative changes in the condylar surfaces, which were substantiated by the calculated fractal dimension value. The data were statistically analyzed. Results The results revealed a significant difference (p-value = 0.041) between the mean fractal valuein the case group's (1.35) and the control group's (1.38) left sides whereas the differences in the mean fractal values between the case and control groups on the right side was not significant (p-value = 0.49). Conclusion It is recommended to use the fractal dimension value and the total degenerative severity score together to quantify degenerative changes in the TMJ OA rather than exclusively relying on fractal value.

Antinociceptive Efficacy of 15-Deoxy-Δ12,14-Prostaglandin J2 Therapy in Response to Experimentally Induced Temporomandibular Joint Arthritis: A Systematic Review of Studies in Rats

The aim of the present systematic review was to assess the antinociceptive efficacy of 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) therapy in rats with experimentally induced temporomandibular joint (TMJ) arthritis. The focused question was “Is 15d-PGJ2 therapy effective in the management of TMJ nociception?” Indexed databases were searched without time and language restrictions up to and including September 2023 using different key words. Original studies were included. Risk of Bias (RoB) was assessed using the SYRCLE tool. Six studies performed in male Wistar rats with experimentally induced TMJ arthritis were included. The observation or follow-up period ranged between 45 min and 14 days. Four studies reported that 15d-PGJ2 therapy retards the production of proinflammatory cytokines in TMJ tissues. Four studies reported that 15d-PGJ2 therapy inhibits leukocyte migration and plasma extravasation in TMJ tissues. In one study, the expression of decay-accelerating factor in TMJ tissues increased after 15d-PGJ2 therapy. One study showed that 15d-PGJ2 inhibits nociception in a dose-dependent manner via the activation of peripheral kappa/delta opioid receptors. Prior sample-size-estimation (SSE) was performed in none of the studies and all studies had a high RoB. Due to a high RoB, methodological variations, and the absence of prior SSE within the included studies, it is demanding to derive an absolute verdict regarding the antinociceptive efficacy of 15d-PGJ2 therapy in response to experimentally induced TMJ arthritis.

A rare case of severe isolated temporomandibular joint involvement in juvenile idiopathic arthritis

Background: Juvenile idiopathic arthritis is an inflammatory condition of unknown etiology. Early temporomandibular joint involvement may be asymptomatic or with mild symptomatology, despite radiological signs of substantial joint damage. Early diagnosis and management is of substantial importance, because orofacial symptoms due to temporomandibular joint arthritis may be disabling and interfere with impaired quality of life or even dentofacial abnormalities. When temporomandibular joint involvement is the first and only manifestation - a very rare event – it is easy to remain undiagnosed. It is noteworthy that the current body of published material on isolated arthritis of the temporomandibular joint is limited to 2 case reports and a multinational cohort of pediatric rheumatology centers.

EROSIVE TEMPOROMANDIBULAR JOINT DISORDER IN A PATIENT WITH ULCERATIVE COLITIS: RAREMANIFESTATION OF ARTHROPATHIES, CASE REPORT

Temporomandibular Joint (TMJ) involvement in patients with ulcerative colitis (UC) is a rare manifestation. To the best of our knowledge there are only two cases in the literature reported the presence of TMJ involvement in a patient with UC. We report a case of 23-year-old female with a two-year history of UC she was complaining of unilateral temporomandibular jaw pain, the pain was severe enough to affect her daily activities, she was not able to speak and there was a limitation of mouth opening. The patient was only able to open her mouth for 2.5 cm. C-reactive protein and erythrocyte sedimentation rate were high, rheumatoid factor was negative. The computed tomography (CT) of the mandible and teeth reveals flattening with erosion of the condylar process of the left mandibular joint without the presence of joint effusion or soft tissue swelling. Our patient was managed by biological treatment Ustekinumab for 6 months, as a result the patient improved and she was able to open her mouth up to 4 cm. Clinicians should be aware of the importance of biological treatment in these circumstances, TMJ arthritis in UC patients is considered a rare and unusual picture of extraintesinal IBD manfistations.

Photobiostimulation conjugated with stem cells or their secretome for temporomandibular joint arthritis in a rat model

BackgroundTemporomandibular joint (TMJ) arthritis is a debilitating, challenging condition and different methods have been implicated for its treatment. This study aimed to test the therapeutic potentials of low-level laser therapy (LLLT) associated with adipose derived stem cells (ADSC) or their derived secretome on a murine model induced arthritis.MethodsForty eight rats were divided into four groups where group I was the sham control, the rest of animals were subjected to arthritis induction using complete Freund’s adjuvant, then divided as follows: group II received phosphate buffered saline (PBS) intraarticular injection and irradiation of 0 j/cm2, group III received ADSCs derived secretome and irradiation of 38 j/cm2, and group IV received ADSCs and irradiation of 38 j/cm2 as well. One and three weeks after treatment, animals were euthanized, and paraffin blocks were processed for histological assessment by hematoxylin and eosin stain with histomorphometrical analysis. Histochemical evaluation of joint proteoglycan content was performed through toluidine blue stain, and immunohistochemical staining by the proinflammatory marker tumor necrosis factor-α (TNF-α) was performed followed by the relevant statistical tests.ResultsThe arthritis group showed histological signs of joint injury including cartilage atrophy, articular disc fibrosis, irregular osteochondral interface, and condylar bone resorption together with high inflammatory reaction and defective proteoglycan content. In contrast, the treated groups III and IV showed much restoration of the joint structure with normal cartilage and disc thickness. The inflammation process was significantly suppressed especially after three weeks as confirmed by the significant reduction in TNF-α positive immunostaining compared to the arthritic group, and the cartilage proteoglycan content also showed significant increase relative to the arthritic group. However, no significant difference between the results of the two treated groups was detected.ConclusionLLLT conjugated with ADSCs or ADSCs derived secretome can efficiently enhance the healing of arthritic TMJs. Stem cell secretome can be applied as a safe, potent therapy. However, further investigations are required to unravel its mechanism of action and pave its way as a safe, novel, cell free therapy.Graphical

E10 Temporo-mandibular joint involvement risk factors in juvenile idiopathic arthritis

Abstract Introduction Recent recommendations suppose temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) is a risk factor of poor outcomes and severe disease course. Objectives To compare the clinical characteristics of patients with juvenile idiopathic arthritis with and without TMJ involvement. Methods We analyzed the data of 753 patients with juvenile idiopathic arthritis aged 2–17 years, depending on TMJ arthritis (n = 43; 5.7%) or no TMJ arthritis (n = 710; 94.3%). Clinical, laboratory characteristics and treatment regimens were compared. Odds ratio (OR) analysis of sensitivity (Se) and specificity (Sp) was performed to obtained the predictors of TMJ involvement. Results Despite the similar age of onset, TMJ arthritis was associated with longer course of the disease, polyarticular JIA category, use of systemic corticosteroids and longer achievement of remission with similar rate of biologic administration. TMJ arthritis was associated with involvement of cervical spine, hip and shoulder arthritis. The main risk factors, associated with TMJ involvement in JIA were active joints &amp;gt; 8 (OR = 14.9 (5.8; 38.3), P = 0.0000001), delayed remission &amp;gt; 7 years (OR = 3.1 (1.6; 5.8), P = 0.0004), delayed hip involvement (OR = 4.6 (0.9; 22.6), P = 0.041), hip osteoarthritis (OR = 4.0 (1.2; 13.0), P = 0.014), and avascular necrosis of the hip. Cervical spine arthritis (OR = 10.3 (5.4; 19.8), P = 0.000001), and corticosteroid treatment (OR = 2.3 (1.2; 4.4), P = 0.0007) were associated with TMJ arthritis. Patients with TMJ arthritis required more biologics (OR-3.2 (1.6; 6.2), P = 0.0006). Oligoarticular JIA category and uveitis were protective against TMJ involvement. Data are in the table. Conclusion TMJ involvement is marker of poor disease prognosis. Early initiation of biologics and avoidance of corticosteroids might improve the risk of TMJ involvement. Ethics Written consent was obtained according to the declaration of Helsinki. This retrospective study's protocol was approved by the local Ethical Committee of Saint Petersburg State Pediatric Medical University (protocol number 11/10 from 23.11.2020).

Преднамеренная искусственная деформация у населения позднесарматского времени (палеопатологический аспект)

Introduction. Intentional artificial head deformation is one of the most striking features of the late Sarmatian nomads from the Eastern European steppes. For quite a long time, archaeologists and anthropologists tried to solve the issues associated with this custom’s emergence and existence in the population of the 2nd – 4 th centuries AD. Later, the question of the deforming structure’s impact on the normal life of a person became a separate research line for the phenomenon of artificial cranial deformation in the late Sarmatians. Methods and materials. 155 craniums of sexually mature late Sarmatian populations (2nd – 4th centuries AD) originating from under the burial mounds in the territory of the Lower Volga region were the material for the study. Comparison of pathological conditions occurrence between the deformed and undeformed skull groups was carried out using nonparametric tests: Pearson’s chi-squared test (χ2) and Fisher’s exact test. Results. Comparative analysis of pathological conditions occurrence on deformed and undeformed skulls in late Sarmatian time has shown that the only deviation in which the compared series differ significantly is temporomandibular joint arthritis. Discussion. The frequency and degree of articular disease development in late Sarmatians with intentional artificial head deformities increase with age. The age-related variability of arthrotic changes in the mandibular joint area indicates the involutionary nature of this condition. At the same time, the absence of statistical differences between age groups in the distribution frequencies of this pathology and its wide distribution in young individuals under 35 years of age suggest that artificial skull deformation is one of the factors stimulating its development. Conclusions. Degenerative changes in the temporomandibular joint area are a statistically more widespread pathology in deformed skulls. The absence of gender differences between the deformed and undeformed skulls in the late Sarmatians, as well as the groups of pathologies associated with diet and the degree of negative factors impacting the natural and social environment, indicates that this custom in the late Sarmatian society did not carry the function of gender or social differentiation. The use of a modifying structure for deliberate artificial cranial deformation is quite compatible with normal human life, and its use did not subsequently lead to the development of serious skull and brain pathologies.

Impact of glycogen synthase kinase-3ß inhibition on rats' temporomandibular joint collagen-induced rheumatoid arthritis with correlation to miRNA-155/miRNA-24 expression.

The current study considered assessing the role of miRNA-155 and miRNA-24 in collagen-induced rheumatoid arthritis (RA) in rats' temporomandibular joint (TMJ). Their role in histological aggressiveness of the disease and therapy response to glycogen synthase kinase (GSK) inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) will be studied. Rats were randomly distributed to four groups (8 rats/group): group I negative control, group II collagen-induced rheumatoid arthritis (CIA), group III Control+TDZD-8 treated group, and group IV CIA+TDZD-8 treated group. Then were euthanized 42 days after the start of the experiment. H&E staining, Masson trichrome staining, and immunohistochemical antibodies against S100 were performed. qRT-PCR of miRNA-155 and miRNA-24 were done for frozen synovial tissues. Histological analysis showed that the most affected structure in induced rheumatoid arthritis of TMJ is the articular disc, condylar head, and subchondral bone. Combined treatment with TDZD-8 improved histological status in the joint. Masson's trichrome (MTC) histochemical staining revealed disarrangement of collagen fibers and adherence between the articular disc and condylar cartilage. Meanwhile, the morphology and collagen composition of the disc and condyle in CIA+ TDZD-8 were similar to those of healthy tissues. Immunohistochemical analysis for S100A4 revealed increased immunoreactivity staining in the CIA group. The immunoreactivity was significantly decreased in CIA+ TDZD-8 treated group. TDZD-8 significantly decreased the levels of miRNA-155 and miRNA-24 in synovial tissue. Our results reveal for the first-time correlation of miRNA-155 and miRNA-24 that might be implicated in the onset of TMJ RA. Consequently, the treatment of CIA with GSK inhibitor (TDZD-8) yields encouraging results. We predicted the TDZD-8 might protect against CIA by suppressing miRNA-155, miRNA-24, and S100A4 protein levels.

Challenges in treating juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) diagnosis and classification is currently still based on clinical presentation and general laboratory tests. Some joints such as the temporomandibular joint (TMJ) and sacroiliac (SI) are hard to assess and define as actively inflamed based on clinical examination. This review addresses these difficult to assess joints and provides the latest evidence for diagnosis and treatment. Recommendations on clinical examination and radiological examination are available. Recent 2021 ACR recommendations were made for TMJ arthritis and in 2019 for sacroiliitis. New evidence to guide clinical suspicion and need for further investigations are available for these hard to assess joints. These guidelines will help healthcare providers in diagnosis and treatment assessment.

Management of temporomandibular joint arthritis in children and adolescents: An introduction for orthodontists.

Juvenile idiopathic arthritis (JIA) is the most common inflammatory rheumatic disease of childhood. JIA can affect any joint and the temporomandibular joint (TMJ) is one of the joints most frequently involved. TMJ arthritis impacts mandibular growth and development and can result in skeletal deformity (convex profile and facial asymmetry), and malocclusion. Furthermore, when TMJs are affected, patients may present with pain at joint and masticatory muscles and dysfunction with crepitus and limited jaw movement. This review aims to describe the role of orthodontists in the management of patients with JIA and TMJ involvement. This article is an overview of evidence for the diagnosis and treatment of patients with JIA and TMJ involvement. Screening for the orofacial manifestation of JIA is important for orthodontists to identify TMJ involvement and related dentofacial deformity. The treatment protocol of JIA with TMJ involvement requires an interdisciplinary collaboration including orthopaedic/orthodontic treatment and surgical interventions for the management of growth disturbances. Orthodontists are also involved in the management of orofacial signs and symptoms; behavioural therapy, physiotherapy and occlusal splints are the suggested treatments. Patients with TMJ arthritis require specific expertise from an interdisciplinary team with members knowledgeable in JIA care. Since disorders of mandibular growth often appear during childhood, the orthodontist could be the first clinician to see the patient and can play a crucial role in the diagnosis and management of JIA patients with TMJ involvement.

Temporomandibular Joint Involvement in Juvenile Idiopathic Arthritis: The Results from a Retrospective Cohort Tertial Center Study.

Our study aimed to evaluate the clinical and laboratory features of juvenile idiopathic arthritis (JIA) children with temporomandibular joint (TMJ) arthritis. In the retrospective cohort study, we analyzed data of 753 patients with JIA aged 2-17 years, depending on TMJ arthritis or not. TMJ arthritis can to be diagnosed in the presence of at least two of the following clinical signs of inflammation: pain in TMJ, jaw opening limitation, jaw opening deviation, and micrognathia. We compared clinical, laboratory, and treatment features in JIA patients depending on the involvement of TMJ. TMJ arthritis was detected in 43 (5.7%) of our patients and associated with a longer course of the disease, polyarticular JIA category, treatment with systemic corticosteroids, and longer achievement of the remission and involvement of cervical spine, hip, and shoulder. Active joints >8 (OR = 14.9, p = 0.0000001), delayed remission >7 years (OR = 3.1; p = 0.0004), delayed hip involvement (OR = 4.6; p = 0.041), hip osteoarthritis (OR = 4.0; p = 0.014), cervical spine arthritis (OR = 10.3, p = 0.000001), and corticosteroid treatment (OR = 2.3, p = 0.0007) were associated with TMJ involvement. Patients with TMJ arthritis require more biologics (OR = 3.2, p = 0.0006, HR = 2.4, p = 0.005) and have decreased probability of remission achievement (p = 0.014). Consequently, TMJ arthritis was associated with a severe disease course. Early biologic treatment and corticosteroid avoidance might decrease TMJ involvement.

Temporalis Myofascial Flap and Conchal Bowl Cartilage Grafting for Temporomandibular Joint Arthritis

Temporomandibular joint (TMJ) arthritis arises from a multitude of etiologies; however, there is no consensus definitive treatment. The complication profile of artificial TMJs is well known, and outcomes are variable and are reserved for salvage attempts. This case details a patient with persistent traumatic TMJ pain, arthritis, and single-photon emission computed tomography scan of potential nonunion. The present study reports on the first novel use of an alternative composite myofascial flap to help arthritic TMJ pain. This study details the successful use of a temporalis myofascial flap and conchal bowl autologous cartilage graft in posttraumatic TMJ degeneration.

MRI of the temporomandibular joint in children with juvenile idiopathic arthritis: protocol and findings.

Contrast-enhanced magnetic resonance imaging (MRI) is the technique of choice for diagnosis and monitoring of temporomandibular joint (TMJ) disorders in patients with juvenile idiopathic arthritis (JIA), as it is able to visualize both soft tissue and osteochondral changes. Approximately 40% of children with JIA develop inflammatory and chronic osteochondral changes observable on imaging, which if left untreated can lead to significant facial growth impairment, including facial asymmetry and retrognathia. MRI of the TMJ plays a paramount role in diagnosis and treatment monitoring in JIA since early signs of TMJ involvement are difficult to detect clinically and with physical examination. Findings of TMJ arthritis may be classified into acute and chronic domains. Early or acute manifestations include joint effusion, bone marrow edema, synovial thickening, and increased joint enhancement. With disease progression, there are characteristic osteochondral changes, including deformity of the mandibular condyle with shortening of the mandibular ramus, bone erosions, and disk abnormalities. In this pictorial essay, we describe a consensus MRI protocol for the study of the TMJ and illustrate the degree of normal and pathological MRI findings using currently available MRI scoring systems of the TMJ developed for JIA.

Therapeutic Potential of Low-level Laser Photobiomodulation on Adjuvant Induced Temporomandibular Joint Arthritis in A Rat Model

Objective: To test the efficacy of low-level laser therapy (LLLT) to alleviate temporomandibular TMJ induced arthritis

Juvenile idiopathic arthritis and the temporomandibular joint: a case-control study of magnetic resonance imaging findings in relation to clinical and psychosocial factors.

In juvenile idiopathic arthritis (JIA), the temporomandibular joint (TMJ) is a particularly challenging joint to assess both clinically and with imaging. The aim of this article is to investigate TMJ magnetic resonance imaging (MRI) findings in relation to clinical and psychosocial factors in patients with JIA and healthy individuals related to TMJ arthritis in JIA. In total, 45 patients (6-16 years) with JIA and 16 healthy age- and sex-matched controls were examined according to the diagnostic criteria for temporomandibular disorders (DC/TMD). The subjects answered questionnaires about psychosocial factors (pain intensity, pain-related disability, depression, stress, catastrophising, pain locations, and jaw function) and underwent bilateral MRI of the TMJ. This study indicates a substantial overlap of TMJ MRI findings in both the inflammatory domain and the damage domain between JIA patients and healthy individuals. In JIA patients, the inflammatory MRI sign of bone marrow oedema seems to influence orofacial pain intensity.

DENTAL TREATMENT OF A CHILD SUFFERING FROM TMJ ANKYLOSIS UNDER GENERAL ANESTHESIA: A CASE REPORT

Temporomandibular joint (TMJ) ankylosis is a joint disorder which refers to bone adhesion of the anatomic joint components, resulting in loss of function [1]. The etiologies of TMJ ankylosis include previous trauma, previous TMJ surgery, arthritis, and infection. It can be congenital, and in some cases, idiopathic. The most common etiology of TMJ ankylosis is previous trauma, with the second being infection [2].

Temporomandibular joint arthritis increases canonical Wnt pathway expression in the articular cartilage and trigeminal ganglion in rats

The canonical Wnt pathway participates in inflammatory diseases and it is involved in neuropathic pain. This study evaluated the immunoexpression of the canonical Wnt signaling pathway in the articular cartilage of the temporomandibular joint (TMJ) and along the nociceptive trigeminal pathway in arthritic rats. For this, male Wistar rats were divided into Control (C) and Arthritic (RA) groups. Arthritis induction was performed through subcutaneous injection of methylated bovine serum albumin (mBSA) and complete Freund Adjuvant (CFA)/ Incomplete Freund Adjuvant (IFA) on the first 14 days (once a week), followed by 3 weekly intra-articular injections of mBSA (10 μl/joint; left TMJ). The following parameters were evaluated: nociceptive threshold, inflammatory infiltrate, type I and III collagen birefringence, immunohistochemistry for IL-1β, TNF-α, IL-6, Wnt10b, β-catenin, cyclin-D1 in articular cartilage, c-Myc in synovial membrane, and immunofluorescence analysis for c-Fos, Wnt-10b and β-catenin in the trigeminal ganglion and the trigeminal subnucleus caudalis. The RA group showed intense articular cartilage damage with proliferation of type III collagen, increased immunoexpression of proinflammatory cytokines and Wnt-10b, β-catenin and cyclin-D1 in the articular cartilage and c-Myc in the synovial membrane. In the RA group, a reduction in the nociceptive threshold was observed, followed by a significant increase in the expression of Wnt-10b in neurons and β-catenin in satellite cells of the trigeminal ganglion. c-Fos immunoexpression was observed in neurons, peripherally and centrally, in arthritic rats. Our data demonstrated that TMJ arthritis in rats causes articular cartilage damage and nociceptive behavior, with increased immunoexpression of canonical Wnt pathway in the articular cartilage and trigeminal ganglion.