Diseased Temporomandibular Joint Research Articles

Study of collagen remodeling in structural disorders of the temporomandibular joint using second-harmonic generation microscopy.

Structural disorder of the temporomandibular joint (TMJ) is a progressive disease with poor prognosis due to its physiological three-dimensional anatomical position and the complicated relationship among muscles, ligaments, and cartilage. The lack of detection methods for changes in the collagen structure of the TMJ disc makes the diagnosis untimely and unclear. This work aimed to explore the feasibility of using a promising detection technique, second-harmonic generation (SHG), to characterize collagen fibers in a TMJ disc with structural disorders. The TMJ discs with structural disorder were observed using SHG microscopy, and assessment of collagen orientation was conducted by analyzing digitized images. The SHG images were also compared with the scanning electron microscopy images and microscopic images acquired after hematoxylin and eosin and Masson's trichrome staining. The SHG imaging showed that the collagen fibers in diseased TMJ were distributed in a disorderly manner, and pixel intensities in diseased TMJ discs were significantly different from those acquired in healthy TMJs. Moreover, the three dimensions of collagen fibers and dynamic images acquired by SHG nonlinear optical microscopy showed the structural disorder of the collagen fibers in a diseased TMJ. In summary, SHG imaging could provide three-dimensional and quantitative data, with dynamic and critical pathological information for clinical diagnosis, showing its potential value in the diagnosis and evaluation of structural disorders of the TMJ disc.

Immunohistochemical Evaluation of Neuroreceptors in Healthy and Pathological Temporo-Mandibular Joint

Aim: A study was performed on the articular disk and periarticular tissues of the temporo-mandibular joint (TMJ) with immunohistochemical techniques to give evidence to the presence of neuroreceptors (NRec) in these sites. Methods: The study was carried out on tissue samples obtained from 10 subjects without TMJ disease and from 7 patients with severe TMJ arthritis and arthrosis. We use antibodies directed against following antigens: Gliofibrillary Acidic Protein (GFAP), Leu-7, Myelin Basic Protein (MBP), Neurofilaments 68 kD (NF), Neuron Specific Enolase (NSE), S-100 protein (S-100) and Synaptophysin (SYN). Results: This study revealed that Ruffini's-like, Pacini's-like and Golgi's-like receptors can be demonstrated in TMJ periarticular tissues and that free nervous endings are present in the subsynovial tissues but not within the articular disk. We observed elongated cytoplamic processes of chondrocytes that demonstrated strong S-100 immunoreactivity but they were unreactive with all other antibodies. These cytoplamic processes were more abundant and thicker in the samples obtained from patients with disease TMJ. Conclusion: The results of this study confirm that different Nrec are detectable in TMJ periarticular tissues but they are absent within the articular disk. In the latter site, only condrocytic processes are evident, especially in diseased TMJ, and they might have been confused with nervous endings in previous morphological studies. Nevertheless the absence of immunoreactivity for NF, NSE and SYN proves that they are not of neural origin.

Novel approach to the study of jaw kinematics in an alloplastic TMJ reconstruction

Total alloplastic temporomandibular joint (TMJ) reconstruction is a reliable treatment modality in patients with severely diseased TMJ with good clinical behaviour. TMJ mandibular function after alloplastic reconstruction has scarcely been analysed as a biomechanical parameter and investigation has generally been limited to interincisal measurements without deeper insight into joint kinematics. Dynamic stereometry to assess condylar movements relative to the fossa was performed at the 5 year follow-up of a patient who underwent condylar resection of the right TMJ followed by total alloplastic joint reconstruction to treat pigmented villonodular synovitis. The patient could achieve wide mouth opening, but overall mandibular kinematics showed a strong deviation towards the prosthetic side due to the lack of mandibular translation caused by the absence of the lateral pterygoid attachment. Possible overloading of the joint contralateral to the TMJ prosthesis might be prevented by optimizing replacement joint design.

Aquaporin 1 expression in human temporomandibular disc

Aquaporins (AQPs) are a family of hydrophobic membrane channel proteins. The expression of several AQP isoforms has been investigated in different human tissues, including the orofacial region. However, information on the role and localization of AQP1 in joints is limited, and no data are available on aquaporins in the normal temporomandibular joint (TMJ) disc. Sixteen human TMJ discs without degenerative changes were taken from fresh cadavers to investigate the presence and distribution of AQP1 by immunohistochemistry. The aim of the study was to gain additional insights into the biomolecular composition of aquaporins and their role in homeostasis of the TMJ. Porcine TMJ discs were also studied by Western blotting for comparison. Scattered AQP1 immunoexpression was detected in human disc cells, documenting its constitutive expression, but differences amongst the three disc regions were not significant. AQP1 expression was demonstrated in porcine TMJ disc by Western blotting. Our findings suggest that AQP1 is normally expressed in the TMJ disc and confirm a role for it in the maintenance of TMJ homeostasis. Further studies are needed to elucidate expression patterns of aquaporins in diseased TMJ discs.

Kinematic Analysis of Mandibular Motion in Patients With Temporomandibular Joint Osteoarthritis

Statement of the Problem: Kinematic properties of the temporomandibular joint (TMJ) in healthy individuals are well reported in the literature. However, there is little information about these kinematic properties of the osteoarthritic TMJ patient. It is important to understand the kinematic properties of the diseased TMJ which in the future can help the clinician make an accurate diagnosis and select appropriate treatment. Therefore, the aim of the present study was to investigate kinematic properties of the TMJ in osteoarthritis patients. The relationship between condylar and incisor range of motion, and total mandibular body rotation was evaluated.

Temporomandibular Joint: Disorders, Treatments, and Biomechanics

Temporomandibular joint (TMJ) is a complex, sensitive, and highly mobile joint. Millions of people suffer from temporomandibular disorders (TMD) in USA alone. The TMD treatment options need to be looked at more fully to assess possible improvement of the available options and introduction of novel techniques. As reconstruction with either partial or total joint prosthesis is the potential treatment option in certain TMD conditions, it is essential to study outcomes of the FDA approved TMJ implants in a controlled comparative manner. Evaluating the kinetics and kinematics of the TMJ enables the understanding of structure and function of normal and diseased TMJ to predict changes due to alterations, and to propose more efficient methods of treatment. Although many researchers have conducted biomechanical analysis of the TMJ, many of the methods have certain limitations. Therefore, a more comprehensive analysis is necessary for better understanding of different movements and resulting forces and stresses in the joint components. This article provides the results of a state-of-the-art investigation of the TMJ anatomy, TMD, treatment options, a review of the FDA approved TMJ prosthetic devices, and the TMJ biomechanics.

Analysis of the Collagen I and Fibronectin of Temporomandibular Joint Synovial Fluid and Discs

The objective of this study was to investigate the content of synovial fluid aspirates and temporomandibular joint (TMJ) disc tissue for collagen I and total fibronectin in patients with closed lock. Fibronectin contains dual properties of assisting with wound healing and inducing cartilage degradation. Native fibronectin has been shown to assist with wound repair, whereas particular fibronectin fragments may degrade cartilage. In addition, collagen I is the major supporting protein of the TMJ disc and will degrade as osteoarthritis progresses. Fibronectin or collagen I expression in human TMJ synovial aspirates and disc tissue may indicate the proteins' involvement in closed lock. The hypothesis of this study is that TMJ discs and serum of patients with closed lock will contain an increased amount of fibronectin and decreased amount of collagen I. We analyzed a total of 8 diseased TMJ discs and 4 diseased synovial fluid aspirates. For our control samples, we assessed 5 synovial samples from healthy patients and control skin samples. Using an enzyme-linked immunosorbent assay allowed us to measure the total amount of fibronectin and collagen I in synovial aspirates. Furthermore, we used light microscopy to assess TMJ disc histology and collagen architecture in control skin samples. Lastly, using fluorescent staining, we examined fibronectin and collagen I expression in TMJ discs. We compared the fluorescent staining and light microscopy results of both proteins within each disc to confirm fibronectin and collagen I expression. Disc specimens with advanced morphologic pathology showed significant labeling for fibronectin in 3 of 3 cases and for collagen I in 4 of 4 cases. There was no considerable difference in detection of either fibronectin or collagen I in TMJ synovial aspirates from patients with advanced disc pathology compared with controls. The levels of fibronectin and collagen I in the TMJ disc and synovial fluid may be influenced by the stage of disease. The results did not provide a clear understanding of fibronectin and collagen I involvement with tissue repair in closed-lock cases. Detection of fibronectin fragments may provide more meaningful results.

Detection of DNA and Immunoreactivity Specific for Mycoplasma fermentans in Synovial Fluid and Sera from Patients with Temporomandibular Joint Disorders

This study investigated whether the presence of Mycoplasma fermentans (M. fermentans) in the temporomandibular joint (TMJ) could be associated with the pathology of temporomandibular joint disorders (TMD). One hundred fifteen synovial fluid (SF) samples from patients with TMD were evaluated for the presence of DNA of M. fermentans by polymerase chain reaction (PCR) assay. Specific antibody against M. fermentans was also detected in the SF as well as sera by Western blot analysis. M. fermentans DNA was identified in 37.4% of the SF samples from the TMD patients. There was no difference between PCR-positive and -negative rate regarding sex and disease categories, e.g., internal derangement (ID) and osteoarthritis (OA). However, the prevalence of M. fermentans DNA in ID patients was higher in elderly patients (73.3%) than in younger patients (31.8%), Anti-M. fermentans innnunoreactivities (IgG) specific for lipoproteins with various molecular sizes, 56 kilo-Dalton (kDa), 48 kDa, 38 kDa, and 29 kDa, were also identified in the SF. The immunoreactivity was also detected in the patients' sera. The reactivity patterns of the anti-M. fermentans antibodies were, however, different between the SF and the sera; reactivities to 48 kDa and 29 kDa lipoproteins were prominent in the former, while the reactivities to those of 56 kDa, 48 kDa, and 29 kDa were evidently increased in the latter. The presence of specific DNA and antibody for M. fermentans in the TMJ implies that M. fermentans could possibly induce joint specific immunoreaction, thus perpetuating the inflammatory reaction in the diseased TMJ.

Specific expression of inducible nitric oxide synthase in the synovium of the diseased temporomandibular joint

The expression of inducible nitric oxide synthase (iNOS) in temporomandibular joint (TMJ) specimens obtained arthroscopically from diseased TMJs was investigated by using immunohistochemistry and compared with clinical, arthroscopic, and histologic findings. Synovial biopsies were obtained arthroscopically from 18 TMJs in 15 patients with symptomatic internal derangement (ID) or osteoarthritis (OA). We also obtained arthroscopic biopsies from 8 control TMJs (3 with habitual luxation of the mandible, one with ID with clicking, and 4 with mandibular condyle fractures). The expression of iNOS was examined by immunohistochemistry and was compared with clinical, arthroscopic, and histologic findings. Definite or intense iNOS immunoreactivity was observed in both the synovial lining cells and the endothelial cells of TMJs with symptomatic ID or OA. Weaker immunoreactivity was present in synovial fibroblasts. In contrast, in TMJs without synovitis (eg, those with habitual luxation of the mandible) the expression of iNOS was weak or marginal. The expression of iNOS correlated significantly with arthroscopic evidence of synovitis (r = 0.406, P <.05) but not with cartilaginous degeneration (P >.05). The expression of iNOS also correlated with the histologic grade of the synovial lining cell layers (r = 0.530, P <.05). However, in patients with ID or OA of the TMJ, there was no statistically significant correlation between the intensity of iNOS immunoreactivity and clinical, arthroscopic, or histologic findings (P >.05). These data clearly suggest that nitric oxide is locally produced in the synovial lining of the TMJ in ID and OA.

Synovial fluid sampling from the temporomandibular joint: sample quality criteria and levels of interleukin-1ß and serotonin

The aims of this study were to compare two sets of quality criteria (SQC A and B) with respect to synovial fluid (SF) sampling and to present temporomandibular joint (TMJ) SF levels of IL-1β and 5-HT. The study comprised 310 TMJ SF samples from 12 healthy individuals (HI) and 59 patients with TMJ inflammatory disorders. Ten HI and 37 patients were selected for investigation of TMJ SF levels and samples wereobtained by a push-and-pull method with quantification by vitamin B12. The SQC comprised aspirate weight (AW), dilution factor (DF), blood contamination and hemolysis. IL-1b and 5-HT levels did not differ between the samples that satisfied SQC A or B. The proportion of samples that satisfied SQC A was higher than for SQC B. Patients with polyarthritides had significantly higher TMJ SF concentrations of 5-HT and IL-1β than HI. In conclusion, there is a recovery of TMJ SF of 0.1–0.2 g with the method used and the criteria set with the highest success rate do not differ from the other one with respect to SF levels of IL-1β and 5-HT. This set of sample quality criteria comprised no hemolysis, no or only minor blood contamination, AW >0.5 g and DF <0.98. The higher SF levels in the diseased TMJ (polyarthritides) compared to the healthy joint with respect to 5-HT and IL-1β is of clinical diagnostic relevance and the presence of 5-HT or IL-1β in TMJ SF seems to indicate a pathological joint condition probably of an inflammatory nature.

Identification of matrix metalloproteinases (MMPs) in synovial fluid from patients with temporomandibular disorder.

Proteolytic enzymes with gelatinolytic activity in the synovial fluid (SF) of temporomandibular joint (TMJ) arthropathies were assayed by gelatin-impregnated gel enzymography. SF samples were collected from 10 TMJs in patients with closed lock (CL) condition and 5 TMJs from asymptomatic healthy volunteers. Two proteinases with gelatinolytic activities at 92 kDa and 72 kDa were detected in both the normal and the diseased TMJs. Also detected were weak bands at molecular weights of 83 kDa and 66 kDa. All of these proteinase activities were inhibited by EDTA and tissue inhibitor of metalloproteinases (TIMP), required Ca2+ for activation, and were detected with gelatin but not casein as substrate, suggesting that these enzymes were matrix metalloproteinases (MMPs). The 72 kDa and 66 kDa bands further reacted with anti-MMP-2 antibody by Western blot analysis, and the proteinases in the TMJ-SF could cleave type IV collagen in vitro without any activation. These four activities identified by enzymography were, therefore, identified as 92 kDa-gelatinase (proMMP-9), 83 kDa-gelatinase (active MMP-9), 72 kDa-gelatinase (proMMP-2) and 66 kDa-gelatinase (active MMP-2). Densitometric analyses of these bands revealed higher levels of the active form of MMP-9 in the CL patients compared to controls. These findings suggest that MMP-2 and -9 could be dominant proteinases in the TMJ-SF and possibly reflect TMJ pathology.