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Synovial fibroblasts contribute to the inflammatory temporomandibular joint under pathogenic stimuli. Synovial fibroblasts and T cells participate in the perpetuation of joint inflammation in a mutual activation feedback, via secretion of cytokines and chemokines that stimulate each other. IL-17 is an inflammatory cytokine produced primarily by Th17 cells which plays critical role in the pathogenesis of numerous autoimmune and inflammatory diseases. Here, we investigated the roles of IL-17A in temporomandibular joint disorders (TMD) using genome-wide analysis of synovial fibroblasts isolated from patients with TMD. IL-17 receptors were expressed in synovial fibroblasts as assessed using real-time PCR. Microarray analysis indicated that IL-17A treatment of synovial fibroblasts upregulated the expression of IL-6 and chemokines. Real-time PCR analysis showed that the gene expression of IL-6, CXCL1, IL-8, and CCL20 was significantly higher in IL-17A-treated synovial fibroblasts compared to nontreated controls. IL-6 protein production was increased by IL-17A in a time- and a dose-dependent manner. Additionally, IL-17A simulated IL-6 protein production in synovial fibroblasts samples isolated from three patients. Furthermore, signal inhibitor experiments indicated that IL-17-mediated induction of IL-6 was transduced via activation of NFκB and phosphatidylinositol 3-kinase/Akt. These results suggest that IL-17A is associated with the inflammatory progression of TMD.

Background: Non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used for the management of pain and inflammation. However, little remains known about the effects of NSAIDs on synovitis of the human temporomandibular joint (TMJ). The aims of this study were to investigate the potential anti-inflammatory effects of NSAIDs on synovitis of the TMJ and the inflammatory effects of PGE2 on fibroblast-like synoviocytes (FLS) derived from the TMJ., Methods: Human synovial tissue was obtained from patients with internal derangement who underwent arthroscopy of the TMJ. FLSs were prepared from the tissues using the outgrowth method. A COX inhibitor (indomethacin or celecoxib) was added to the IL-1β-stimulated cells in culture. The cells were also stimulated with PGE2 or an EP agonist. The PGE2 production and COX-2 and IL-6 expression levels were examined using enzyme-linked immunosorbent assays, real-time PCR, and a microarray analysis., Results: COX inhibitors decreased not only PGE2 production, but also the expression of COX-2 and IL-6 in FLS stimulated with IL-1β. EP2 and EP4 were both expressed in the FLS, and the treatment with EP2 and EP4 agonists induced IL-6 production in these cells., Conclusion: The COX inhibitors indomethacin and celecoxib reduce the expression of inflammatory factors, such as COX-2 and IL-6, in FLS from the TMJ via suppression of PGE2 production. EP2 and EP4 were the main receptors for PGE2 present in the FLS. The approach used in this study may be useful for revealing how drugs such as NSAIDs affect the cellular functions of FLS from the TMJ., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) are key mediators of the intracapsular pathological conditions of the temporomandibular joint (TMJ). Therefore, the gene expression profiles in synovial fibroblast-like cells (SFCs) from patients with internal derangement of the TMJ were examined after they were stimulated with IL-1β or TNF-α to determine which genes were altered., Methods: Ribonucleic acid was isolated from SFCs after IL-1β or TNF-α treatment. Gene expression profiling was performed using oligonucleotide microarray analysis. On the basis of the results of this assay, we investigated the kinetics of macrophage inflammatory protein-3α (MIP-3α) gene expression using PCR, and protein production in TMJ SFCs stimulated by IL-1β or TNF-α using an ELISA. Inhibition experiments were performed with MAPK and NFκB inhibitors. SFCs were stimulated with IL-1β or TNF-α after treatment with inhibitors. The MIP-3α levels were measured using an ELISA., Results: Macrophage inflammatory protein-3α was the gene most upregulated by IL-1β- or TNF-α stimulation. The mRNA and protein levels of MIP-3α increased in response to IL-1β in a time-dependent manner. In contrast, during TNF-α stimulation, the MIP-3α mRNA levels peaked at 4 h, and the protein levels peaked at 8 h. In addition, the IL-1β- and TNF-α-stimulated MIP-3α production was potently reduced by the MAPK and NFκB signaling pathway inhibitors., Conclusion: Interleukin-1β and TNF-α increased the MIP-3α production in SFCs via the MAPK and NFκB pathways. These results suggest that the production of MIP-3α from stimulation with IL-1β or TNF-α is one factor associated with the inflammatory progression of the internal derangement of the TMJ., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Synovitis, which is characterized by the infiltration of inflammatory cells, often accompanies progression of temporomandibular joint disorder (TMD) symptoms. Because IL-1β is elevated in synovial fluids obtained from TMDs, we hypothesized that IL-1β-responsive genes in synoviocytes may help identify the putative genes associated with synovitis. Using microarray analysis, we found that monocyte chemoattractant protein-1 (MCP-1) mRNA levels were elevated in IL-1β-stimulated synoviocytes. MCP-1 is a member of the chemokine superfamily. The production of MCP-1 was increased in synoviocytes treated with IL-1β. When IL-1β was injected into the cavities of rat TMJs, inflammatory cells and MCP-1-positive cells were detected in the synovial tissues. Furthermore, MCP-1 levels were higher in synovial fluids from individuals with pain compared with those without pain. Inhibitors of MAP-kinases and NF-κB reduced IL-1β-induced MCP-1 production. These results suggest that MCP-1 stimulated by IL-1β is one of the factors associated with the inflammatory progression of TMDs.

Background: In this study, we analyzed the gene expression profile of fibroblast-like synoviocyte (FLS) cultures from the temporomandibular joint (TMJ) to identify candidate genes associated with intracapsular pathologic conditions of TMJ. Cyclooxygenase (COX)-2 was one of the genes in FLS upregulated following stimulation by interleukin (IL)-1beta, a cytokine thought to play a key role in several pathological conditions. This study investigated the expression of COX-1 and COX-2 in cultured human FLS and rat TMJ synovium following stimulation with IL-1beta., Methods: RNA was isolated from human FLS after IL-1beta treatment. COX-1 and -2 expression was examined using a GeneChip and real-time polymerase chain reaction. Prostaglandin E(2) (PGE(2)) levels in conditioned media from FLS were measured using enzyme-linked immunosorbent assay. Synovial tissues from TMJs of IL-1beta-injected rats were examined for COX-1 and COX-2 expression by immunohistochemical staining., Results: Following treatment of FLS with IL-1beta, expression of the COX-2 gene increased up to 8 h and peaked at 4 h, whereas COX-1 expression did not change. Stimulation with IL-1beta increased the level of PGE(2) in conditioned media of cultured FLS in a time-dependent manner up to 48 h. Immunohistochemistry showed a strong positive staining for COX-2 in the lining and sub-lining synovial tissues of the TMJ of IL-1beta-injected rats. In contrast, staining for COX-1 was the same in synovial tissues with and without IL-1beta injection., Conclusion: These data suggest that COX-2 expression stimulated by IL-1beta stimulates the production of PGE(2) in FLS and plays important roles in the progression of inflammation in TMJ.

Objective: This study aimed to investigate the severity of arthroscopically observed pathologies and the levels of a set of inflammatory cytokines in aspirated synovial fluid (A-SF) in patients with chronic closed lock (CCL) of the temporomandibular joint (TMJ) before and after visually guided TMJ irrigation (VGIR). Furthermore, the findings were correlated with the clinical outcome after VGIR., Study Design: VGIR was performed in 56 consecutive patients with unilateral CCL. Forty-nine of them, who underwent a second VGIR either as a follow-up arthroscopy or as a repeated therapeutic irrigation, were analyzed. They were assigned to either the successful (s-) group (n = 31) or unsuccessful (u-) group (n = 18), according to the clinical success criteria. The severity of arthroscopic findings of osteoarthritis (OA), synovitis, and fibrous adhesion (FA) were evaluated as arthroscopic scores. The levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, IL-12, and IL-10 in the A-SF were measured. At the first and second VGIR, the arthroscopic scores and the levels of each investigated cytokine were compared between the s- and u-groups. In each group, same parameters were compared between the first and second VGIR., Results: At the first and second VGIR, there are no differences in the arthroscopic scores between the s- and u-groups. After the first VGIR, the severity of synovitis significantly improved, that of OA was unchanged, and that of FA became worse in the s- and u-groups. At the first VGIR, the levels of IL-6 and IL-8 were significantly higher in the u-group, and the IL-10 level was significantly higher in the s-group. At the second VGIR, however, there were no differences in the levels of each investigated cytokine between the s- and u-groups. The levels of each cytokine did not significantly change between the first and second VGIR, regardless of the clinical outcome., Conclusions: VGIR may contribute to the remission of synovitis in patients with TMJ CCL. However, the severity of arthroscopically observed pathologies and the levels of each investigated cytokine do not seem to be reflected by the clinical state. Moreover even if the intra-articular inflammation is asymptomatic, an exacerbation may not be ruled out even after a successful VGIR.

Purpose: This study investigates selected predictors for clinical outcome of temporomandibular joint (TMJ) irrigation in patients with chronic closed lock (CCL)., Patients and Methods: Fifty-six patients with unilateral CCL, who underwent a visually guided TMJ irrigation (VGIR), were enrolled in this study. They were divided into either successful (s-group; n = 38) or unsuccessful groups (u-group; n = 18), according to the clinical success criteria. The investigated predictive factors were age, gender, duration of symptoms before the VGIR, preoperative painless range of mandibular motion, preoperative self-evaluated TMJ pain on visual analog scale (VAS), severity of arthroscopically observed pathologies, and presence and concentrations of a set of pro- and anti-inflammatory cytokines (ie, tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, IL-8, IL-12, and IL-10) in the aspirated synovial fluid (A-SF). Several comparative analyses and logistic regression analyses were used for statistical studies., Results: The preoperative VAS score, detection rate of IL-8, and concentrations of IL-6 and IL-8 in the A-SF were significantly higher in the u-group (P < .05). Conversely, the detection rate and concentrations of IL-10 were significantly higher in the s-group (P < .05). The multivariate adjusted odds ratio (OR) showed that the detectable IL-10 in the A-SF (OR, 10.882; P = .047) is significantly predictive for a successful VGIR., Conclusions: The presence of IL-10 in the A-SF is a significant predictor of successful outcome of TMJ irrigation for CCL. Severe TMJ pain and detectable IL-6 or IL-8 in the A-SF seem to indicate a poor outcome after TMJ irrigation.

Background: Interleukin (IL)-1beta is thought to play a key role in several pathologic conditions of the temporomandibular joint (TMJ). Gene expression profile of synovial fibroblasts stimulated with IL-1beta was studied by oligonucleotide microarray analysis to elucidate candidate genes associated with intracapsular pathologic conditions of TMJ., Methods: RNA was isolated from synovial fibroblasts from five patients after IL-1beta treatment. Gene expression profiling was performed with a GeneChip. Changes in gene expression were determined by comparing IL-1beta-treated cells with untreated cells., Results: A total of 121 genes showed a greater than threefold difference in average intensity between untreated and IL-1beta-treated synovial fibroblasts in five experiments. Five chemokines were among the 10 most upregulated genes, and the most upregulated gene was CCL20. The 121 IL-1beta-responsive genes included 12 chemokines whose mRNA levels were confirmed by real-time PCR., Conclusion: These data should provided useful information about the pathologic conditions of TMJ, especially in support of diagnosis and therapeutic approaches to TMJ.

Objective: This study investigated the correlation of clinical outcomes of temporomandibular joint (TMJ) irrigation with the occurrence and concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, IL-12, and IL-10 in the washed-out synovial fluid (SF) in patients with chronic closed lock (CCL) of the TMJ., Study Design: Thirty-six patients underwent a visually guided TMJ irrigation (VGIR). SF samples were collected immediately before VGIR. The patients were divided into either successful (s-group; n = 25) or unsuccessful groups (u-group; n = 11). The detection rates and concentrations of each cytokine per milligram of total protein in the SF were measured, and then compared between the s- and u-groups., Results: All of the investigated cytokines were detectable with various rates, concentrations, and combination patterns. The detection rate and concentrations of IL-6 were significantly higher in the u-group, and those of IL-10 were significantly higher in the s-group., Conclusions: The investigated cytokines were suggested to be involved in the pathophysiology of TMJ CCL. The results also suggest that IL-6 in the SF is an indicator of an unsuccessful outcome, and that IL-10 is a significant predictor of a successful outcome of TMJ irrigation for CCL.

Objective: This study aimed to explore the clinical course following visually guided irrigation (VGIR) for chronic closed lock (CCL) of the temporomandibular joint (TMJ) as well as the factors of importance for clinical outcome. Evaluation emphasis was placed on the period needed for the patients to reach the success criteria., Study Design: Sixty-one patients with unilateral CCL comprised the study group. The cumulative success rate of VGIR and the additional surgical treatments following VGIR were studied. The 61 patients were divided into either the good outcome (g) group or poor outcome (p) group on the basis of whether they reached the success criteria within 3 months postoperatively, and clinical and arthroscopic factors were correlated with the clinical outcome of VGIR., Results: The cumulative success rate of VGIR increased up to the 6-month follow-up (success rate of 72.1%) but did not change after that point in time. A repeated VGIR (success rate of 87.5%) was performed in 8 patients. Open TMJ surgery (success rate of 87.5%) was performed in 8 patients, 7 of whom had an interfering condylar osteophyte. A pronounced reduction of preoperative painless range of mandibular motion (P-ROM) and advanced osteoarthritis (OA) were more frequently found in the p-group than in the g-group. The multivariate adjusted odds ratio showed that a decreased preoperative P-ROM was significantly predictive for a poor outcome of VGIR., Conclusions: The efficacy of VGIR is clinically acceptable as an initial surgical treatment for TMJ CCL. A 6-month follow-up period ought to be sufficient for outcome assessment of VGIR. A pronounced reduction of preoperative P-ROM should be considered as a risk factor for delay of the postoperative improvement, and OA changes may sometimes affect the clinical outcome of VGIR.

The aim of this study was to investigate the changes in the state of arthroscopically observed fibrous adhesions (FA) after visually guided irrigation (VGIR) and the influence of FA on clinical outcome in patients with chronic closed lock of the temporomandibular joint (TMJ). Forty-eight TMJs of 48 patients with unilateral chronic closed lock were enrolled in this study. All 48 joints underwent VGIR twice. After the first VGIR (immediately before the second VGIR), clinical outcome was assessed as regards maximal interincisal opening (MIO) and self-evaluated TMJ pain (VAS). Thirty patients were symptom-free (good outcome group) and the remaining 18 patients had symptoms (poor outcome group). In each group, the changes of the MIO, VAS and severity of FA (FA score) after the first VGIR were studied. The influence of FA score in the first and second VGIR on clinical outcome was analyzed by logistic regression analysis. There was no joint with disappearance or reduction of FA after the first VGIR. In both groups, MIO and VAS were significantly improved after the first VGIR even though the state of FA became significantly worse. The multivariate logistic regression analysis showed that the risk of poor outcome for FA scores in the first and second VGIR were 0.89-times (95% CI: 0.33-2.40, P=0.82) and 1.76-times (95% CI: 0.54-5.73, P=0.35), respectively. The dose-response relationships between FA scores in the first or second VGIR were not significant. In conclusion, our results indicate that the presence of FA or a postoperative worsening of FA (including postoperative new FA formation) seems not to affect the clinical outcome as regards MIO and VAS in patients with chronic closed lock of the TMJ.

Background: Synovitis, which is characterized by infiltration of inflammatory cells, often accompanies progression of clinical symptoms of the temporomandibular joint (TMJ). Synovial fibroblasts of the TMJ are believed to play important roles in progression of synovitis. The purpose of this study was to examine production and gene expression of chemokines by synovial fibroblasts stimulated by tumor necrosis factor-alpha (TNF-alpha)., Methods: Protein levels of chemokines were measured by enzyme-linked immunosorbent assay (ELISA). Gene expression of chemokines was analyzed by real-time polymerase chain reaction (PCR)., Results: Production of interleukin (IL)-8, growth-related oncogene (GRO)-alpha, monocyte chemoattractant protein (MCP)-1, and regulated upon activation normal T-cell expressed and secreted (RANTES) protein by synovial fibroblasts was increased by TNF-alpha. In contrast, stromal cell-derived factor (SDF)-1alpha, macrophage inflammatory protein (MIP)-1alpha and -1beta were not detectable in conditioned media of synovial fibroblasts, with or without TNF-alpha treatment. Increases in gene expression of IL-8, GRO-alpha, MCP-1, and RANTES in response to TNF-alpha treatment were detected., Conclusions: Increased protein production and gene expression of chemokines by synovial fibroblasts in response to TNF-alpha treatment appears to play an important role in recruitment of inflammatory cells into synovium and the progression of synovitis in the TMJ.

Objective: Visually guided irrigation (VGIR) is simple joint irrigation with minimally invasive intracapsular inspection through the use of a thin arthroscope. The aims of the present study were to develop VGIR for the superior joint compartment of the temporomandibular joint (TMJ) by using a 1.2-mm-diameter rod-lens arthroscope and to examine the short-term clinical outcomes. The correlation between the clinical outcome of VGIR of the TMJ and intracapsular findings was also evaluated., Study Design: Twenty patients who underwent VGIR for symptomatic internal derangement of the TMJ (n = 20) were enrolled in this study. The clinical outcome of VGIR was evaluated in terms of the improvement in the painless range of mandibular motion (ROM: interincisal distance in millimeters), and functional jaw pain was evaluated by using a visual analog scale (VAS) ranging from 0 to 100. Painless ROM and VAS scores 6 months postoperatively were compared with the preoperative data. A good clinical outcome was defined as an increased ROM (ROM > 38 mm) and a decreased VAS score (VAS score < 20%, and <60% of the preoperative level). With respect to these criteria, all joints were classified into either good clinical outcome (GO) or poor clinical outcome (PO) groups. The difference in the distribution of the arthroscopic findings obtained during VGIR, with respect to severity, was analyzed between the GO and PO groups., Results: None of the 20 patients experienced any serious local or systemic complications, including the breakage of instruments. We were able to perform a reliable intracapsular diagnosis during VGIR. Sixteen of 20 patients (80%) had significant improvements in postoperative painless ROM and the VAS score of functional pain, thereby being classified into the GO group. The distribution of the severity of intracapsular findings did not differ significantly between the GO group and the PO group., Conclusions: VGIR is useful for the treatment and diagnosis of internally deranged TMJs. These data suggest that the clinical outcome of TMJ irrigation is not related to the intracapsular condition of the superior joint compartment.

Objective: The aim of this study was to evaluate the clinical outcome after visually guided irrigation (VGIR) of the temporomandibular joint (TMJ) and its relationship with postoperative arthroscopic changes., Study Design: Of the original 69 patients, thirty patients (30 TMJs) underwent VGIR of the TMJ a second time. After the first VGIR, the clinical outcome was assessed, and 18 patients were assigned to the good outcome group. The remaining 12 patients were assigned to the poor outcome group. The arthroscopic findings related to the articular surface, synovial lining, and fibrous adhesion scores were recorded. Then, the arthroscopic findings in the first and second VGIR were compared., Results: The intra-articular tissue status between the first and second VGIR was unchanged in approximately 40% of all joints. No significant differences with respect to an improvement in tissue status were found when the good outcome and poor outcome groups were compared., Conclusions: In patients with chronic closed lock of the TMJ, a clinical improvement after VGIR does not seem to be accompanied by improved intra-articular tissue status.

Purpose: The aim of this study was to examine intra-articular conditions in unloaded temporomandibular joints (TMJs) after mandibulectomy including the condyle or segmental mandibulectomy., Patients and Methods: Seventeen joints were defined as unloaded TMJs. Eleven of the 17 joints were classified into the "without condyle" (WOC) group in which TMJs had the condyle removed but the disc and superior joint compartment were preserved, and remaining 6 joints were classified into the "with condyle" (WC) group in which TMJs were connected to the condylar process. Disc configuration, bony changes, and joint effusion were examined by magnetic resonance imaging. In 8 of the 17 joints, arthroscopic examination of the superior joint compartment was performed. Correlation between data of the WOC and WC groups was evaluated. The relationship between arthroscopic findings and joint effusion was also analyzed., Results: Deformed discs were observed in 7 of the 11 joints (63.6%) of the WOC group but were not observed in the WC group, in which there was a normal relationship between the disc and condyle. Bony changes were not detected in any joints. Joint effusion and arthroscopically diagnosed fibrous adhesion were observed in nearly all joints of both groups., Conclusions: We conclude that alteration of the relationship between the disc and condyle is more important for the initiation of disc deformation than loading conditions on the disc. The present findings suggest that, in the unloaded TMJs, articular degeneration is induced by disturbance of synovial fluid metabolism but that bony conditions are not affected., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofacial Surg 61:437-441, 2003)

Objective: 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., Study Design: 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., Results: 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)., Conclusion: These data clearly suggest that nitric oxide is locally produced in the synovial lining of the TMJ in ID and OA.

The expression and distribution of inducible nitric oxide synthase (iNOS) was examined in 12 samples of human temporomandibular joint (TMJ) with internal derangement (ID) and four control specimens. In the diseased joints, strong or definite iNOS reactivity was expressed in synovial lining and endothelial cells; weaker activity was present in synovial fibroblasts. In contrast, although there was weak expression of iNOS in synovial fibroblasts and endothelial cells in the two control specimens, there was no iNOS staining in the synovial lining cell layers. This original report that iNOS is expressed in the synovial tissue of the temporomandibular joint indicates that nitric oxide is produced locally at least in the synovial lining in these joints when affected by internal derangement.

Purpose: This study explored the morphologic changes and clinical symptoms related to the temporomandibular joint (TMJ) associated with long-term lack of mandibular continuity., Patients and Methods: The subjects were 20 patients (40 TMJs) who underwent mandibulectomy including the condyle or segmental mandibulectomy without mandibular reconstruction more than 6 months previous to the study. The 40 TMJs were classified into the following 3 groups: group I: TMJs with a major mandibular fragment including the mandibular body (n = 21), group II: TMJs with a minor mandibular fragment including only the condylar process or the mandibular ramus (n = 10), and group III: TMJs without a condyle (n = 9). All TMJs were examined with respect to disc position, condylar position, bony changes, and appearance of joint effusion on magnetic resonance imaging, as well as for the presence of joint or muscle pain and joint noise., Results: The rate of anterior disc displacement was 28.6% in group I, 10.0% in group II, and 100% in group III. All condyles in group I were located in the glenoid fossa. Seven of 10 condyles in group II were dislocated anteriorly out of the glenoid fossa. However, these condyles were situated in the intermediate zone of the disc. Osteoarthritic changes was found in 1 joint in group II. Joint effusion was not observed in group I. However, joint effusion was detected in the posterior region of the upper joint compartment in 7 of 10 TMJs in group H and in 8 of 9 TMJs in group III. In group II, the 7 TMJs with joint effusion were the same joints with anteriorly dislocated condyles. Clinical symptoms of TMJ pain, TMJ noise, or muscular pain were not found in any patients., Conclusions: Partial mandibulectomy does not affect the relationship between the disc and the condyle or the bony condition of the TMJ. The disc without a condyle will become anteriorly displaced with time. The condyle not connected to the mandibular body often dislocates anteriorly out of the glenoid fossa, while retaining a normal relationship with the disc. Joint effusion, which is detected in nonfunctional TMJs, is not associated with an inflammatory reaction in the joint compartment.

Purpose: This study evaluated the complications of temporomandibular joint (TMJ) arthroscopic lysis and lavage performed using the triangulation technique., Patients and Methods: The 202 consecutive patients (301 joints) who underwent arthroscopic lysis and lavage between 1992 and 1995 were retrospectively surveyed. The preoperative diagnosis of all patients was anterior disc displacement without reduction., Results: Complications were observed in 31 (10.3%) of 301 cases of arthroscopic lysis and lavage. Of these, otologic complications were found in 26 cases (8.6%): blood clots in the external auditory canal in 9; laceration of external auditory canal in 7; partial hearing loss in 5; ear fullness in 2; vertigo in 1; and perforation of tympanic membrane with laceration of external auditory canal in 1. Neurologic injuries were found in 5 cases (1.7%): fifth cranial nerve injuries in 3; and seventh cranial nerve injuries in 2. No other complications were observed., Conclusions: A high level of understanding of the regional anatomy helps reduce the complications associated with arthroscopic lysis and lavage in the TMJ.

Objective: The purpose of this study was to determine whether there is a relationship between synovial fluid levels of nitric oxide and clinical and arthroscopic findings of synovitis or cartilaginous degeneration., Study Design: Arthroscopic surgery was performed on 20 joints in 15 female patients with internal derangement and osteoarthritis of the temporomandibular joint. Synovial fluid aspirates were obtained immediately before arthroscopy. Synovial fluid was also obtained from 14 joints of 11 female asymptomatic volunteers. The concentration of nitrite in the fluid recovered from each temporomandibular joint was measured through use of a highly sensitive and specific chemiluminescence detection method, calibrated per 1 mg of synovial fluid protein and expressed as nitric oxide; the result was then compared with clinical and arthroscopic findings of synovitis and cartilaginous degeneration., Results: Significantly higher levels of nitric oxide (median, 0.331 micromol/mg) were seen in the patients with internal derangement and osteoarthritis than in the control group (median, 0.001 micromol/mg; P<.0001). Synovial fluid from joints with pain in the joint area had significantly higher levels of nitric oxide than did fluid from joints without such pain. Synovial fluid from joints with degenerative changes (median, 0.467 micromol/mg) had significantly higher levels of nitric oxide than did fluid from joints without osteoarthritis (median, 0.057 micromol/mg; P<.05). Although the levels of nitric oxide in synovial fluid aspirates were markedly elevated in some joints with synovitis, there was no correlation between the levels of nitric oxide and the presence of synovitis., Conclusions: The findings indicate that increased levels of nitric oxide are involved in the pathogenesis of cartilaginous degeneration of the temporomandibular joint.

Purpose: The purpose of this study was to determine the prevalence of morphological changes in the superior and inferior surfaces in the temporomandibular joint (TMJ) disc and relate them to disc displacement., Materials and Methods: Thirty TMJs obtained from fresh cadavers were studied. The TMJs were dissected, and the superior and inferior surfaces of the disc were inspected and classified as intact, irregular, or perforated. These findings were corrolated to the position of the disc., Results: There was a greater prevalence of morphologic changes in the inferior (57%) than in the superior surface (17%) of the disc (P < .001). This was found for joints both with normal disc position and those with disc displacement. There was no relationship between surface irregularities of the inferior surface and the position of the disc. Perforation was seen more frequently in joints with disc displacement than in those with normal disc position., Conclusion: Morphologic changes in the inferior surface of the TMJ disc are more prevalent than those in the superior surface, but this is not related to disc position. However, this needs to be considered when doing arthroscopy of only the superior joint compartment.

Objective: To measure the levels of the proinflammatory cytokines, interleukin (IL)-1 beta, IL-6, tumor necrosis factor- (TNF) alpha, IL-8, and interferon- (IFN) gamma in synovial fluid samples taken from patients with temporomandibular disorders (TMD)., Study Design: We studied 6 asymptomatic volunteers and 51 patients with TMD. The IL-1 beta, IL-6, TNF-alpha, IL-8, and IFN-gamma levels in temporomandibular joint synovial fluid were measured using enzyme-linked immunosorbent assay., Results: Measurable level of at least one cytokine in the synovial fluid was found in 40 (64.5%) of 62 joints in the patients: IL-1 beta and IFN-gamma were each detected in 18 (29.0%) of 62 joints; IL-6 in 13 (21.0%) of 62 joints; IL-8 in 11 (19.3%) of 57 joints; and TNF-alpha in only 5 (8.1%) of 62 joints. None of these cytokines was detectable in the synovial fluid in the control group. Furthermore, there was a strong correlation between the detection of IL-1 beta and pain in the joint area., Conclusions: These data clearly demonstrate increased levels of several proinflammatory cytokines in certain patients with TMD and suggest that these cytokines may play a role in the pathogenesis of synovitis and degenerative changes of the cartilaginous tissue and bone of the temporomandibular joint.

Objective: The objective of this study was to measure nitric oxide activity in synovial fluid samples taken from patients with temporomandibular disorders., Study Design: We investigated six volunteers without symptoms and 56 patients with temporomandibular disorders. Nitric oxide activity was measured in temporomandibular joint synovial fluid with a highly sensitive and specific chemiluminescence detection method., Results: A detectable nitrite concentration was found in only 1 of 10 joints in the control group. Measurable levels (> 0.001 mol/l) of nitrites in the synovial fluid were found in 8 (72.7%) of 11 joints with disk derangement with clicking, 24 (85.7%) of 28 joints with disk derangement with locking, and all 26 (100%) joints with osteoarthritis. The mean nitrite concentrations in the temporomandibular joint synovial fluid in the disk derangement with clicking, disk derangement with locking, and osteoarthritis groups were significantly higher than that in the control group (p < 0.05, p < 0.001, p < 0.001, respectively)., Conclusions: These data clearly show increased nitric oxide production in certain temporomandibular disorders and suggest that nitric oxide may play a role in the pathogenesis of synovitis and degenerative changes of cartilaginous tissue and bone of the temporomandibular joint.

A fibrous adhesion into upper joint compartment of the TMJ is indicated by a secondary pathological condition of disk displacement. The fibrous adhesion increases resistance to motion in the joint because the condyle translation has been disrupted. Fibrous adhesion cases resist splint therapy, manipulation technique and manipulation-while-pumping the upper joint compartment. Diagnosis of fibrous adhesion into upper joint compartment is important for internal derangement of the TMJ. The diagnosis depends on information from double contrast arthrotomography of the TMJ. But double contrast arthrotomography findings of fibrous adhesion into upper joint compartment of the TMJ have been recognized in few reports. We have described the varied conditions of the fibrous adhesion into the upper joint compartment of the TMJ by double contrast arthrotomographic findings. These cases confirmed the fibrous adhesion into the upper joint compartment of the TMJ by arthroscopy. Double contrast arthrotomographic findings were as follows: 1. Narrow fibrous band-like structure is observed into upper joint compartment of the TMJ. 2. A partial expansion of the upper joint compartment can be seen with a contrast medium injection. Also positional change of this stenosis decreases in both open and closed jaw positions.

A fibrous adhesion into upper joint compartment of the TMJ is indicated by a secondary pathological condition of the disk displacement. A fibrous adhesion increases resistance to motion in the joint because condyle translation disrupted. The treatment for this condition is too difficult. On this paper, we presented to arthroscopic findings of 4 cases of the fibrous change and fibrous adhesion into upper joint compartment of the TMJ (1) and arthroscopic sweeping as the treatment procedure (2). On these cases, we compared double contrast arthrotomographic findings with arthroscopic findings (3). (1) On the arthroscopic findings, banddle like fibrous adhesion, wide areal fibrous adhesion, and wide areal fibrous change of the articular surfaces were observed. These findings varied to case by cases. (2) The arthroscopic sweeping and lysis performed on this four cases. The clinical symptoms prior to arthroscopic surgery, improved post surgically in all cases. (3) The fibrous lesions in the upper joint compartment was presumed by double contrast arthrotomography that demonstrated by arthroscopy.