Xing Long

Role of NF-κB in TNF-α-induced COX-2 Expression in Synovial Fibroblasts from Human TMJ

In the temporomandibular joint (TMJ) synovium, cyclo-oxygenase-2 (COX-2) expression has been believed to be directly related to joint pain and synovitis. Here we investigated the role of Nuclear Factor κB (NF-κB) in the regulation of COX-2 expression in synovial fibroblasts from human TMJ induced by tumor necrosis factor-α (TNF-α). By reverse-transcriptase/polymerase chain-reaction (RT-PCR) and Western blotting analysis, TNF-α induced a dose- and time-dependent increase in COX-2 expression. Electrophoretic mobility shift assay (EMSA) revealed that transient NF-κB activation in the COX-2 promoter was triggered by TNF-α. In parallel with transient NF-κB activation, the rapid translocation of NF-κB, particularly the p65 subunit, from the cytoplasm into the nucleus was demonstrated. Pre-treatment with pyrolidine dithiocarbamate (PDTC), one of the NF-κB inhibitors, prevented binding to the COX-2 promoter and expression of COX-2 protein in response to TNF-α. These findings indicate that activation of NF-κB is responsible for TNF-α-induced COX-2 expression in synovial fibroblasts from the TMJ.

Superior dislocation of mandibular condyle into the middle cranial fossa: A case report

A case of superior dislocation of the mandibular condyle into the middle cranial fossa is presented. A modified method of reducing the mandibular condyle was used, and restitution of the perforated glenoid fossa was achieved by a combination of titanium plate and repair of the articular disk.

A randomized controlled trial of superior and inferior temporomandibular joint space injection with hyaluronic acid in treatment of anterior disc displacement without reduction

PURPOSE To compare the outcome of inferior and superior joint space injection of sodium hyaluronate in patients with disc displacement without reduction of the temporomandibular joint (TMJ). MATERIALS AND METHODS One hundred twenty patients with disc displacement without reduction of TMJ were randomized into 2 experimental groups. One group of patients received superior joint space injections of sodium hyaluronate and the other group was treated with inferior joint space injections. Patients TMJ status and clinical symptoms were evaluated at the 3 and 6 month follow-up appointments. The clinical parameters recorded were maximal mouth opening (MMO), pain intensity on a visual analog scale (VAS), and modified Helkimos clinical dysfunction index and analyzed with ANCOVA. RESULTS Fifty of the superior and 54 of the inferior joint space injection therapy group returned for the 3 and 6 month evaluations; 86.67% of the patients were retained in the follow-up. MMO, VAS, and Helkimos index of both groups improved at the 3 and 6 month follow-ups. The results of MMO changes and TMJ function were almost the same in both groups at 3 month follow-up. However, there was a significant reduction in TMJ pain in the inferior joint injection group at 3 month follow-up compared with the superior joint injection group (P< .001). There were also significant differences between the inferior joint injection group and superior joint injection group in MMO (P< .005), VAS (P< .001), and Helkimos index (P< .001) at 6 month follow-up. CONCLUSION This study showed that inferior joint space injection with sodium hyaluronate is a valid method of treating disc displacement without reduction of TMJ and a long-term study will be needed to assess the effect of inferior joint injection on the morphologic changes of the TMJ.

Use of synovium-derived stromal cells and chitosan/collagen type I scaffolds for cartilage tissue engineering

The objective was to investigate synovium-derived stromal cells (SDSCs) coupled with chitosan/collagen type I (CS/COL-I) scaffolds for cartilage engineering. CS/COL-I scaffolds were fabricated through freeze-drying and cross-linked by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. SDSCs were isolated from synovium and cultured onto CS/COL-I scaffolds, constructs of which were incubated in serum-free chondrogenic medium with sequential application of TGF-β1 and bFGF for up to 21 days and then implanted into nude mice. The physical characteristics of the scaffolds were examined. The quality of the in vitro constructs was assessed in terms of DNA content by PicoGreen assay and cartilaginous matrix by histological examination. The implants of the constructs were evaluated by histological and immunohistochemical examinations and reverse transcription PCR. Results indicated that the CS/COL-I scaffold showed porous structures, and the DNA content of SDSCs in CS/COL-I scaffolds increased at 1 week culture time. Both of the constructs in vitro and the implants were examined with positive stained GAGs histologically and the implants with positive collagen type II immunohistochemically. RT-PCR of the implants indicated that aggrecan and collagen type II expressed. It suggested that SDSCs coupled with CS/COL-I scaffolds treated sequentially with TGF-β1 and bFGF in vitro were highly competent for engineered cartilage formation in vitro and in vivo.

Insulin-like growth factor-1 boosts the developing process of condylar hyperplasia by stimulating chondrocytes proliferation.

OBJECTIVE The etiology of Condylar hyperplasia (CH) of human temporomandibular joint (TMJ) remains largely unknown. Our previous study has demonstrated that enriched insulin-like growth factor-1(IGF-1) was expressed in the proliferation and hypertrophic layers of CH cartilage. Accordingly, this study was aimed to investigate whether IGF-1 regulates CH chondrocytes proliferation in condylar cartilage overgrowth and explore the molecular mechanism of IGF-1 involved in. METHODS Chondrocytes were isolated from 6 CH and 3 normal cartilage (NC) specimens and cultured in alginate beads or monolayer, treated with IGF-1 or specific inhibitors such as 7-[trans-3-[(azetidin-1-yl)methyl]cyclobutyl]-5-(3-benzyloxyphenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine (NVP-AEW541), U0126, and LY294002. Thereafter, cellular proliferation capacity was evaluated by Cell Viability Analyzer (alginate beads culture) or 3-(4,5-dimethylthiazo(-2-yl)-2,5-diphenyltetrazolium bromide (MTT) (monolayer culture). Gene expression levels of IGF-1, IGF-1 receptor (IGF-1R), collagen type II, type X and those genes associated with proliferation were evaluated by realtime PCR. Protein levels of IGF-1 and IGF-1R synthesized by CH chondrocytes were accessed by enzyme-linked immunosorbent assay (ELISA) and western blotting. RESULTS CH chondrocytes enhanced cellular proliferation capacity and expressed significantly higher levels of messenger RNA (mRNA) and protein expressions of IGF-1 and IGF-1R, as compared with NC chondrocytes. Furthermore, enriched IGF-1 enhanced CH chondrocytes proliferation, up-regulated the expressions of specific genes associated with cellular proliferation and elevated the gene expression of collagen type II A1 (COL2A1). Besides, IGF-1-mediated CH chondrocytes proliferation mainly depended on the mitogen-activated protein kinase (MAPK)-ERK pathway. CONCLUSIONS IGF-1 promotes human TMJ cartilage overgrowth in the developing process of CH by enhancing chondrocytes proliferation via MAPK-ERK pathway.

Boundary-Lubricating Ability and Lubricin in Synovial Fluid of Patients With Temporomandibular Joint Disorders

PURPOSE This study was conducted to measure the boundary-lubricating ability and lubricin concentration of synovial fluid (SF) from patients with different stages of temporomandibular joint disorders (TMDs) and establish relationships between them. PATIENTS AND METHODS According to the imaging and clinical findings, TMD patients were divided into 3 subgroups: displaced disc with reduction, displaced disc without reduction, and osteoarthritis. The boundary-lubricating ability of SF was determined by the coefficient of friction (COF) of SF in vitro with a friction apparatus. The lubricin concentrations were quantified by enzyme-linked immunosorbent assays. RESULTS The COF of SF in TMD patients was significantly higher than that of healthy control subjects, but no observed difference was found among patient subgroups. Furthermore, a significant decline in lubricin concentrations was found in the group with osteoarthritis, whereas there was no significant change in the other groups. However, a significant correlation was not found between the COF and the lubricin concentrations in our study. CONCLUSIONS These findings showed that distinct changes in lubricin and boundary-lubricating ability in the SF occurred with different stages of TMDs.

Modified trans-oral approach for mandibular condylectomy.

Different approaches to the mandibular condyle have been described. In this paper, a modified trans-oral technique to access the mandibular condyle is described and illustrated. This technique was used in a small group of patients; the clinical outcomes are promising. The technique can be used in various temporomandibular joint (TMJ) operations, such as condylar resection, high condylectomy or tumor removal. It provides adequate intra-oral surgical access to the mandibular condyle and avoids complications from extra-oral approaches to the TMJ.

The clinical and radiographic characteristics of condylar osteochondroma

Osteochondroma is one of the most common benign bone tumors, but it is rare in the mandibular condyle. The purpose of this study was to increase the clinical and radiographic cognition of osteochondroma in the mandibular condyle. Thirty-four patients with radiographic and pathologic features of unilateral condylar osteochondroma were included in this retrospective study. All cases received clinical and radiographic examinations before tumor resection. Common manifestations included facial asymmetry, hypomobility, malocclusion, joint dysfunctions, and even external auditory canal stenosis. Osteochondroma might arise on the different condylar areas, such as the medial aspects (55.9%), anterior-superior (11.8%), posterior-superior (11.8%), lateral (8.8%), and generally enlarged (11.8%). The tumor formed a pseudojoint under the anterior eminence in 55.9%; the affected mandible presented normal shape in 58.8%; and horizontal mandibular deviation was caused by the tumor or elongated ramus in 70.6%. The condylar osteochondroma may locate in different positions encircling the condyle, which increases recognition and diagnosis of these lesions.

Immediate autotransplantation of mandibular third molar in China

OBJECTIVE Tooth autotransplantation is a useful surgical method to replace a nonrestorable tooth. We reported our experiences in the replacement of mandibular nonrestorable molars by immediate autotransplantation in a Chinese population. STUDY DESIGN Thirty-five mandibular third molars with open or closed apices from 34 patients were autotransplanted into the same or contralateral fresh recipient sites immediately after the extraction of the nonrestorable mandibular molars. Root canal treatment was routinely performed in the closed-apical molars within 1 month after surgery. Clinical and radiographic examination of the transplanted donor molars was done after surgery. RESULTS Two teeth were been extracted for progressive root resorption. The remaining 33 autotransplanted teeth were asymptomatic and functioning after a mean follow-up period of 5.2 years. No infection, ankylosis, loss of the transplants, or root resorption was noted in the remaining autotransplanted teeth. CONCLUSION Immediate autotransplantation of the mandibular third molar is a reasonable and alternative treatment to replace a nonrestorable tooth in China.

Cone beam CT sialography of Stafne bone cavity

Stafne bone cavity (SBC) was mostly described as a small oval radiolucency in the posterior mandibular region. To the best of our knowledge, the literature does not contain any report of the use of cone beam CT (CBCT) sialography for the diagnosis of this entity. The aim of this paper is to present a large, irregular and expanded atypical SBC, which made diagnosis difficult. A CBCT sialography was performed to get a definite diagnosis of this rare entity.