Relationship Between Intracapsular Fracture Patterns and Arthroscopic Findings.

PURPOSE: To observe the superior joint compartment (SJC) using ultrathin arthroscopy in intracapsular condylar fracture (ICF) of the temporomandibular joint, describe the changes, and evaluate the relations among fracture pattern, arthroscopic findings, and clinical outcome. PATIENTS AND METHODS: Twenty patients with 27 ICFs were the subject group. Thirteen patients had unilateral ICFs and 7 had bilateral ICF. The fracture patterns were classified into 9 categories, and all patients had arthroscopic examination of the traumatized joint at the time of definitive treatment. At 4 months after treatment of the injury, all patients had a secondary arthroscopy of the ICF joint. In all patients, range of motion (ROM) was measured as the interincisal distance (millimeters) at the first visit to 12 months after the first treatment, and the data were statistically evaluated. RESULTS: Intra-articular hyperemia, hypervascularity, and temporal bone damage were found, and 4 patients had disc perforations at the first examination. At the second arthroscopy 4 months later, normal healing occurred in 11 joints, all of which had minimally displaced fractures. Fifteen joints showed complete filling of the SJC, all of which had a displaced minor fragment from the fossa. Comparison of the effect of the presence versus absence of SJC fibrosis on ROM showed marked differences from 1 to 12 months. The effect of early versus delayed definitive treatment showed marked differences at 4 and 12 months. CONCLUSION: The intra-articular condition at 4 months after ICF as observed arthroscopically was related to the minor fragment position. If the minor fragment is nondisplaced, then it will heal to a normal state; however, if the minor fragment is displaced from the fossa, then the SJC shows disc damage and fibrosis. This could lead to fibrous ankylosis.

Gene Expression Profiling of IL-17A-Treated Synovial Fibroblasts from the Human Temporomandibular Joint.

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.

Effects of interleukin-1ß and tumor necrosis factor-α on macrophage inflammatory protein-3α production in synovial fibroblast-like cells from human temporomandibular joints.

BACKGROUND: Interleukin-1ß (IL-1ß) 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-1ß or TNF-α to determine which genes were altered. METHODS: Ribonucleic acid was isolated from SFCs after IL-1ß 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-1ß or TNF-α using an ELISA. Inhibition experiments were performed with MAPK and NFκB inhibitors. SFCs were stimulated with IL-1ß 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-1ß- or TNF-α stimulation. The mRNA and protein levels of MIP-3α increased in response to IL-1ß 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-1ß- and TNF-α-stimulated MIP-3α production was potently reduced by the MAPK and NFκB signaling pathway inhibitors. CONCLUSION: Interleukin-1ß 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-1ß or TNF-α is one factor associated with the inflammatory progression of the internal derangement of the TMJ.

The anti-inflammatory effect of cyclooxygenase inhibitors in fibroblast-like synoviocytes from the human temporomandibular joint results from the suppression of PGE2 production.

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-1ß-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-1ß. 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.

Repeated Live Imaging in the Temporomandibular Joint of an Anterior Crossbite Mouse Model Using a 7T Magnetic Resonance Device.

BACKGROUND/AIM: Few studies have performed magnetic resonance (MR) imaging on live animals. The aim of this study was to perform 7T MR microimaging of the temporomandibular joint (TMJ) multiple times in the same living mice with malocclusion, and to compare between MR imaging and histopathological findings. MATERIALS AND METHODS: Mice were examined by MR imaging at 3-4, 6 and 12 weeks following the attachment of a metal tube on the left mandibular incisor. Histopathological examination was done at 3, 6 and 12 weeks. RESULTS: The detailed structure of the TMJ was evident from MR microimaging. The histopathological examination showed some changes in the cartilage, but no changes in the bone structure of these mice. CONCLUSION: We successfully performed multiple 7T MR imaging in living mice. Even if the TMJ showed no obvious changes on MR images, minute changes may be present in the cartilage.

Clinical guidelines for total temporomandibular joint replacement.

Total joint replacement (TJR) of the temporomandibular joint (TMJ) is a promising surgical procedure and device for treating end-stage diseases of the TMJ. For the functional and aesthetic reconstruction of the oral and maxillofacial head and neck region, TMJ TJR significantly helps maintain the patient's quality of life in terms of a better diet, mastication, speech and social interaction. TMJ TJR was approved by regulatory authorities in 2019 in Japan, thus enabling the clinical application of the TJR system. However, the surgery demands particularly difficult and high-risk procedures, necessitating the prudent selection of indicated patients. The joint committee of the Japanese Society of Oral and Maxillofacial Surgeons and Japanese Society for Temporomandibular Joint is working together to develop an appropriate clinical guideline for TMJ TJR.

MicroRNA-204 regulates osteogenic induction in dental follicle cells.

The dental follicle is an ectomesenchymal tissue surrounding developing tooth germ that contains osteoblastic-lineage-committed stem/progenitor cells. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression during stem cell growth, proliferation, and differentiation. The aim of this study was to investigate the key regulators of miRNA during osteogenic differentiation in human dental follicle cells (hDFC). We analyzed miRNA expression profiles in hDFC during osteoblastic differentiation. Expression of miR-204 was decreased in hDFC during osteogenic induction on microarray analysis. Real-time and RT-PCR analysis also showed that the expression of miR-204 was decreased in all three hDFC during osteogenic differentiation. To investigate whether miR-204 has an effect on osteogenic differentiation, miR-204 was predicted to target alkaline phosphatase (ALP), secreted protein acidic and rich in cysteine (SPARC), and Runx2 in the in the 3'-UTRs by in silico analysis. When miR-204 was transfected into hDFC, the activity of ALP and protein levels of SPARC and Runx2 were decreased. mRNA levels of ALP, SPARC and Runx2 were also decreased by miR-204 transfection. Our data suggest that miR-204 negatively regulates the osteogenic differentiation of hDFC by targeting the bone-specific transcription factor Runx2, the mineralization maker ALP and the bone extracellular matrix protein SPARC.

1,25(OH)2D3 regulates collagen quality in an osteoblastic cell culture system.

The active form of vitamin D, 1,25(OH)(2)D(3), has a broad range of effects on bone, however, its role in the quality of bone matrix is not well understood. In this study, using an osteoblastic cell (MC3T3-E1) culture system, the effects of 1,25(OH)(2)D(3) on collagen cross-linking and related enzymes, i.e., lysyl hydroxylases (LH1-3) and lysyl oxidases (LOX, LOXL1-4), were examined and compared to controls where cells were treated with cholecalciferol or ethanol. When compared to the controls, gene expressions of LH1, LH2b and LOXL2 were significantly upregulated by 1,25(OH)(2)D(3) up to 72h of culture. In addition, hydroxylysine (Hyl), Hyl aldehyde (Hyl(ald)), Hyl(ald)-derived cross-links and a total number of cross-links of collagen were significantly higher and the cross-link maturation was accelerated in the 1,25(OH)(2)D(3) treated group. These results demonstrate that 1,25(OH)(2)D(3) directly regulates collagen cross-linking in this culture system likely by upregulating gene expression of specific LH and LOX enzymes.

Cytokine and clinical predictors for treatment outcome of visually guided temporomandibular joint irrigation in patients with chronic closed lock.

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.

Stimulatory Effects of CO(2) Laser, Er:YAG Laser and Ga-Al-As Laser on Exposed Dentinal Tubule Orifices.

We investigated the effects of lasers irradiation on the exposed dentinal tubule. Human tooth specimens with exposed dentinal tubule orifices were used. Three types of lasers (CO(2) laser, Er:YAG laser and Ga-Al-As laser) were employed. The parameters were 1.0 W in continuous-wave mode with an irradiation time of 30 s for the CO(2) laser, 30 mJ in continuous-wave mode with an irradiation time of 60 s for the Er:YAG laser, and 1.0 W in continuous-wave mode with an irradiation time of 60 s for the Ga-Al-As laser. A non-irradiated group was used as a control. After laser irradiation, the dentinal surface of each sample was observed using SEM. Afterwards, all samples were immersed in methylene blue dye solution in order to evaluate the penetration of the dye solution and observe the change in dentinal permeability after laser irradiation. SEM observation showed that the control group had numerous exposed dentinal tubule orifices, whereas these orifices were closed in the laser-irradiated groups. There was consistent dye penetration into the pulp chamber in the control group, whereas no dye penetration was evident in the laser-irradiated groups. Therefore, laser appears to be a promising treatment for reducing permeation through exposed dentinal tubules.

Capacity of Human Dental Follicle Cells to Differentiate into Neural Cells In Vitro.

The dental follicle is an ectomesenchymal tissue surrounding the developing tooth germ. Human dental follicle cells (hDFCs) have the capacity to commit to differentiation into multiple cell types. Here we investigated the capacity of hDFCs to differentiate into neural cells and the efficiency of a two-step strategy involving floating neurosphere-like bodies for neural differentiation. Undifferentiated hDFCs showed a spindle-like morphology and were positive for neural markers such as nestin, ß-III-tubulin, and S100ß. The cellular morphology of several cells was neuronal-like including branched dendrite-like processes and neurites. Next, hDFCs were used for neurosphere formation in serum-free medium containing basic fibroblast growth factor, epidermal growth factor, and B27 supplement. The number of cells with neuronal-like morphology and that were strongly positive for neural markers increased with sphere formation. Gene expression of neural markers also increased in hDFCs with sphere formation. Next, gene expression of neural markers was examined in hDFCs during neuronal differentiation after sphere formation. Expression of Musashi-1 and Musashi-2, MAP2, GFAP, MBP, and SOX10 was upregulated in hDFCs undergoing neuronal differentiation via neurospheres, whereas expression of nestin and ß-III-tubulin was downregulated. In conclusion, hDFCs may be another optimal source of neural/glial cells for cell-based therapies to treat neurological diseases.

Plasma rich in growth factors stimulates proliferation, migration, and gene expression associated with bone formation in human dental follicle cells.

BACKGROUND/PURPOSE: Plasma rich in growth factors (PRGFs), which is prepared from autologous blood from patients, has been reported with regards to bone regeneration for dental implants. Human dental follicle cells (hDFCs) have the capacity to commit to multiple cell types such as the osteoblastic lineage. The aim of this study is to evaluate the effects of PRGFs for mineralization in hDFCs. MATERIALS AND METHODS: PRGFs was prepared from whole blood centrifuged at 460g for 8 minutes. hDFCs isolated from the dental follicle with collagenase/dispase were cultured with growth medium or osteogenic induction medium (OIM) containing PRGFs or fetal bovine serum. Concentrations of the growth factors were examined using an enzyme-linked immunosorbent assay kit. A cell migration assay was used for two-dimensional movement. Gene expressions were examined with real-time polymerase chain reaction using a DyNAmo SYBR Green quantitative polymerase chain reaction kit. RESULTS: The platelet concentration in PRGF Fraction 2 was 2.14-fold higher than in whole blood. White blood cells were not detected in PRGFs. Transforming growth factor-ß levels were higher than insulin-like growth factor-1, platelet-derived growth factor-AB and -BB, and vascular endothelial growth factors in PRGF Fraction 2. Proliferation and migration by hDFCs increased in OIM supplemented with PRGFs in a dose-dependent manner and were higher in hDFCs cultured in OIM plus 10% PRGFs compared with OIM plus 10% fetal bovine serum. PRGFs upregulated the gene expression of type I collagen, osteomodulin, alkaline phosphatase, bone morphogenic protein-4, and transforming growth factor-ß in hDFCs. CONCLUSION: PRGFs may promote bone regeneration due to it including high levels of growth factors.

Simultaneous paresthesia of the lingual nerve and inferior alveolar nerve caused by a radicular cyst.

The inferior alveolar nerve is sometimes affected by periapical pathoses and mandibular cysts. However, mandibular intraosseous lesions have not been reported to disturb the lingual nerve. A case of simultaneous paresthesia of the right lingual nerve and the right inferior alveolar nerve is presented. The possible mechanisms of this extremely uncommon condition are discussed.

Comparison of intraoral radiography and computed tomography in evaluation of formation of bone after grafting for repair of residual alveolar defects in patients with cleft lip and palate.

For one year we studied postoperative computed tomograms (CT) and intraoral radiographs for 29 patients with unilateral alveolar clefts. Interdental bone height and the bony boundary on the nasal side were assessed on intraoral films and compared with the evaluation by CT. Twenty-four cases had adequate interdental bone height as assessed by intraoral films. However, 10 of these 24 cases showed insufficient anteroposterior depth on CT. Two of the remaining five cases were also overestimated by the intraoral radiograph. All cases had sufficient bony boundary on the nasal side on intraoral radiography. However, CT showed that bone formation on the nasal side off two cases was significantly worse than that on the non-cleft side. Consequently, about 40% of surgical outcomes may be overestimated by intraoral radiographs. CT therefore seems to give a better assessment of the clinical outcome than intraoral radiographs and should be considered as an adjunct in difficult clinical cases.

Regional differences of type II collagen synthesis in the human temporomandibular joint disc: immunolocalization study of carboxy-terminal type II procollagen peptide (chondrocalcin).

The purpose of this study was to determine the regional differences of distribution of the carboxy-terminal type II procollagen peptide (pCOL-II-C; chondrocalcin) as markers of cartilaginous expression in the human temporomandibular joint (TMJ) disc. Twelve human TMJ discs without morphologic abnormalities were obtained from 12 fresh cadavers. All specimens were analysed for pCOL-II-C expression using polyclonal rabbit anti-human pCOL-II-C antibody in avidin-biotin-peroxidase complex staining. The results were demonstrated that the percentage of pCOL-II-C immunoreactive disc cells was significantly higher in the outer part (the articular surfaces) than in the inner part (the deep central areas) of the disc. These findings suggest that the tissue heterogeneity of cartilaginous expression reflects the functional demands of the remodelling process in the human TMJ disc.

Visually guided irrigation for patients with symptomatic internal derangement of the temporomandibular joint: a preliminary report.

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.

Distraction osteogenesis for reconstruction after mandibular segmental resection.

Distraction osteogenesis with the shortening and lengthening method is a well-established procedure for repairing extremities. We used this technique for reconstruction after mandibular segmental resection. A 74-year-old woman underwent distraction osteogenesis with an intraoral device, initially shortening the mandible after a 20-mm-long segmental resection, followed by lengthening at a rate of 0.8 mm per day for 21 days. Eight weeks after the distraction, the device was removed and a dental implant was placed at the site of distraction. Radiographic observation showed new bone formation, and the implant was completely osseointegrated. Although the follow-up period is relatively short, the clinical course was uneventful. Distraction osteogenesis with the shortening and lengthening method seems to be a feasible option for reconstruction after segmental resection of the mandible.

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

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.

Visually guided temporomandibular joint irrigation in patients with chronic closed lock: clinical outcome and its relationship to intra-articular morphologic changes.

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.

Comparative study of intra-articular irrigation and corticosteroid injection versus closed reduction with intermaxillary fixation for the management of mandibular condyle fractures.

OBJECTIVE: To evaluate the clinical outcome of a modified conservative treatment protocol involving intra-articular irrigation and corticosteroid injection into the superior joint compartment (SJC) of patients with fresh mandibular condyle fractures. Study design A total of 26 consecutive unilateral fresh condylar fractures in 26 patients were divided into the intra-articular irrigation (IR) group (14 patients, 14 joints) and the conventional conservative treatment (CC) group (12 patients, 12 joints). In the IR group, the SJCs of the fractured joints were irrigated with saline solution and injected dexamethazone sodium, followed by conventional rehabilitation. In the CC group, patients were treated by closed reduction with intermaxillary fixation (IMF) for 2 weeks, followed by conventional rehabilitation. Clinical outcome at 1 month, 3 months, 6 months, and 1 year after injury was determined by clinical examination of jaw motion, joint pain, and occlusal changes. The posttreatment results were compared with the pretreatment baseline data. Between-group differences in clinical parameters were analyzed. RESULTS: There were significant between-group differences in the range of mandibular motion at 1 month and 3 months after injury (1 month, P=.0022; 3 months, P=.0022). In the IR group, joint pain was well relieved from the early stage of treatment. Occlusal changes were found in 1 patient in the IR group and 4 patients in the CC group at 1 year after injury. CONCLUSIONS: The modified treatment protocol involving intra-articular irrigation and corticosteroid injection into the SJC is a more effective and quick-acting modality than conventional closed reduction with IMF for functional recovery and control of clinical symptoms of patients with unilateral fresh condylar fractures.