The Regrowth of Mandibular Coronoid Process After Coronoidectomy: A Retrospective Analysis of 57 Cases.

PURPOSE: Coronoidectomy is carried out frequently as a part of the cranial-maxillofacial surgery procedure. There are few articles on the fate of coronoid process after coronoidectomy, except that several case reports mentioned that coronoid process had regenerated. This study aimed to radiographically access the anatomic outcomes of coronoid process and investigate which factors were associated with the outcomes after coronoidectomy. MATERIALS AND METHODS: A retrospective cohort study included patients undergoing coronoidectomy over a 7-year period. The primary outcome variable was the new coronoid process occurrence (yes/no). Secondary outcome variable was the type of the new coronoid process by evaluating its size, shape and position. Radiograph at 1-year postoperative visit was used to determine the outcomes. The predictor variables included age, sex, surgical purpose, surgical side, surgical approach and the maximal interincisal opening. Appropriate statistics were analyzed by SPSS version 22. χ2 test and binary logistic regression were used to assess the association between predictor factors and anatomic outcomes (P <.05). RESULTS: The study sample included 57 patients. In total, 96 coronoidectomies were performed. Seventy-four coronoid processes (77.1%) showed complete (n = 44, 45.8%), nonunion (n = 19, 19.8%) or partial (n = 11, 11.5%) regrowth, whereas no evidence of regeneration in 22 sites was observed radiographically at 1-year postoperative visit. Binary logistic regression showed that a young age (odds ratio 0.704; 95% confidence interval 0.562-0.882; P = .002) was significantly associated with regeneration of coronoid process. CONCLUSIONS: Coronoid process can mostly regenerate after coronoidectomy. A young age may contribute to regrowth of coronoid process.

The Long-Term Clinical Outcomes of Selectively Extracranial Radiofrequency Thermocoagulation for Trigeminal Neuralgia Guided by Three-Dimensionally Printed Personalized Template.

ABSTRACT: The purpose of this study was to assess the long-term pain relief and the complications of selectively extracranial radio-frequency thermocoagulation (RFT) for trigeminal neuralgia (TN) guided by a three-dimensionally (3D) printed personalized template. The authors conducted a retrospective study of 117 TN patients, who were treated with selectively extracranial RFT under 3D printed personalized template guidance between September 2014 and January 2019. The mean follow-up duration was 42.8 months (range: 28-83 months). Favorable pain relief of patients was 100% at discharge, 86.3% at 1 year, 80.3% at 2 years, 78.6% at 3 years, and 75.4% at 5 years. No complication associated with a puncture or intracranial complication was observed during or after RFT. Postoperative complications included facial numbness in 91 patients (77.8%), masticatory muscle weakness in 15 patients (12.8%), ear paresthesia in 3 patients (2.6%), limited mouth opening in 2 patients (1.7%), and taste hypesthesia in 2 patients (1.7%). Most of these symptoms were improved during the visits and their life was not severely affected. Selectively extracranial RFT guided by a 3D printed personalized template is a clinically practical, effective, and safe approach for TN patients.

Standard orthodontic treatment after condylectomy for patients with active unilateral condylar hyperplasia.

INTRODUCTION: Unilateral condylar hyperplasia (UCH) is a progressive, nonneoplastic overgrowth of the condyle of the temporomandibular joint. For treating active UCH, a popular method combines orthognathic surgery with high condylectomy and orthodontic treatment. The goal of this study was to introduce a new method to correct asymmetry for active UCH. METHODS: Retrospectively, 47 patients with active UCH were divided into horizontal-type, vertical-type, and combined-type. All patients were treated with condylectomy plus postsurgery standard orthodontics (CPSO) with applied miniscrews implanted in infrazygomatic crest and hard palate to intrude affected side of maxillary molars and apply intermaxillary traction for contralateral molars. Cone-beam computed tomography was taken at presurgery, postsurgery, and the end of orthodontics (T3). RESULTS: In the vertical (n = 10) and combined (n = 28) types, deviation of the chin and the canting of the mandible and maxillary occlusal plane were significantly reduced at T3. A difference in the torque of bilateral maxillary first molar (U6) and bilateral mandibular first molar (L6) was significantly reduced at T3. The anterior, superior, and posterior joint spaces in the vertical-type and combined-type were significantly decreased at T3 compared with postsurgery. In contrast, in the horizontal-type group (n = 9), the deviation of the chin was corrected; however, the canting of the mandible and maxillary occlusal plane was significantly increased at T3 compared with presurgery. CONCLUSIONS: CPSO restored facial and occlusal symmetry for vertical-type and combined-type active UCH and returned affected-side condyle to the glenoid fossa. However, CPSO was not suitable for treating the horizontal-type UCH.

LncRNA PVT1 induces chondrocyte apoptosis through upregulation of TNF-α in synoviocytes by sponging miR-211-3p.

Temporomandibular joint osteoarthritis (TMJ OA) is an important subtype of temporomandibular disorders (TMD). Articular cartilage destruction is considered a common pathological feature of TMJ OA, which is reported to be mainly induced by chondrocyte apoptosis. Synovial sterile inflammation is an initial factor of TMJ OA-associated articular cartilage destruction. Therefore, determining the mechanism of synovial membrane inflammation-induced articular cartilage destruction in TMJ OA is important for the TMJ OA therapy. In this study, we detected the function of synoviocytes in chondrocyte apoptosis under lipopolysaccharide (LPS)-induced inflammatory conditions and explored the underlying mechanism. We found that synoviocytes in inflammatory conditions facilitated LPS-induced chondrocytes apoptosis by secreting increased Tumor Necrosis Factor α (TNF-α), which was induced by long non-coding RNA plasmacytoma variant translocation 1 (PVT1) upregulation. PVT1 served as a competing endogenous RNA that sponged the microRNA miR-211-3p and prevented the inhibition of TNF-α expression. In conclusion, our in vitro study revealed that PVT1 has a previously unknown role in chondrocyte apoptosis, which may also be a mechanism underlying synoviocyte involvement in TMJ OA.

HMGB1-induced angiogenesis in perforated disc cells of human temporomandibular joint.

High mobility group 1 protein (HMGB1), a highly conserved nuclear DNA-binding protein and inflammatory mediator, has been recently found to be involved in angiogenesis. Our previous study has demonstrated the elevation of HMGB1 in the tissue of perforated disc of temporomandibular joint (TMJ). Here, we investigated a novel mediator of HMGB1 in regulating hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) to mediate angiogenesis in perforated disc cells of TMJ. HMGB1 increased the expression of HIF-1α and VEGF in a dose- and time-dependent manner in these cells. Moreover, immunofluorescence assay exhibits that the HIF-1α were activated by HMGB1. In addition, HMGB1 activated extracellular signal-related kinase 1/2 (Erk1/2), Jun N-terminal kinase (JNK), but not P38 in these cells. Furthermore, both U0126 (ErK inhibitor) and SP600125 (JNK inhibitor) significantly suppressed the enhanced production of HIF-1α and VEGF induced by HMGB1. Tube formation of human umbilical vein endothelial cells (HUVECs) was significantly increased by exposure to conditioned medium derived from HMGB1-stimulated perforated disc cells, while attenuated with pre-treatment of inhibitors for VEGF, HIF-1α, Erk and JNK, individually. Therefore, abundance of HMGB1 mediates activation of HIF-1α in disc cells via Erk and JNK pathway and then, initiates VEGF secretion, thereby leading to disc angiogenesis and accelerating degenerative change of the perforated disc.

Clinical Efficacy Evaluation for Treating Trigeminal Neuralgia Using a Personalized Digital Guide Plate-Assisted Temperature-Controlled Radiofrequency.

The aim of this study was to explore the application and efficacy of personalized digital guiding plate-aided radiofrequency in treating trigeminal neuralgia (TN). A total of 117 cases (93 patients) of TN from January 2015 to December 2016 were divided into the study group (n = 53) and the traditional group (n = 64). Patients in the study group were treated by the radiofrequency through a personalized digital guiding plate, whereas those in the traditional group were treated by the traditional method. We found that no significant difference between these 2 groups in age, sex, and divisions affected (V2, V3). However, the values for operation time, recurrence rate, and patient's satisfaction in the plate assisted group were significantly improved compared with those in the traditional group. Therefore, the personalized digital guiding plate-assisted radiofrequency has higher application value than traditional method.

IL-1ß-regulating angiogenic factors expression in perforated temporomandibular disk cells via NF-κB pathway.

BACKGROUND: A high density of blood vessels is observed in the perforated disks of temporomandibular joint (TMJ), but the underlying mechanism is unknown. This study aimed to explore the regulation of disk angiogenesis in the perforated disks. METHODS: Expressions of vascular endothelial growth factor (VEGF), angiogenin-1 (Ang-1), chondromodulin-1 (ChM-1), and thrombospondins-1 (TSP-1) were compared between healthy and perforated TMJ disk cells with or without interleukin-1ß (IL-1ß) incubation. The tube formation, cell migration, and expressions of matrix-metalloproteinases (MMPs) in human umbilical vein endothelial cell line (HUV-EC-C) were investigated in conditional media of disk cells. Western blot was performed to determine protein level of VEGF, Ang-1, ChM-1 and TSP-1 in IL-1ß-induced disk cells cultured by NF-κB- or P38-specific pathway inhibitors, respectively. RESULTS: Conditional media from perforated disk cells induced more tube formation, cell migration, and MMPs' expression in HUV-EC-C. Expressions of VEGF and Ang-1 were significantly higher, and ChM-1 and TSP-1 were lower in perforated disks compared to healthy disks. The VEGFA concentration was 291.1 ± 36.09 pg/ml in perforated disk cell conditioned media, markedly larger than that in NDCCM (144.9 ± 33.69 pg/ml). IL-1ß induced VEGF through NF-κB signaling pathway and Ang-1 through p38 MAPK pathway, while repressed expression of ChM-1 and TSP-1 was through NF-κB pathway. Blockade of each pathway markedly restrained inducing effect of cultural media on HUV-EC-C tube formation and migration. CONCLUSIONS: Perforated disk cells secreted more angiogenic factors which might induced via NF-κB pathway.

IL-1ß mediating high mobility group box protein-1 expression in condylar chondrocyte during temporomandibular joint inflammation.

BACKGROUND: Temporomandibular joint (TMJ) osteoarthritis(OA)characterized with cartilage degen-eration is associated with inflammation. High mobility group box chromosomal protein-1(HMGB-1)is a potent mediator of inflammation and the trigger of OA. The expression of HMGB-1 in TMJ OA was uncovered, but the role of HMGB-1 in TMJ cartilage degeneration is not fully understood. In this study, the regulation of HMGB-1 in TMJ condylar cartilage was revealed. METHODS: A complete Freund's adjuvant (CFA)-induced TMJ inflammation animal model was employed and the expression of HMGB-1 was detected at 1st, 2nd, and 6th weeks by immunohistochemistry. TMJ condylar chondrocytes were incubated with IL-1ß (10 and 40 ng/ml) at 24, 48, and 72 h, and the translocation and protein level of HMGB-1 were evaluated by immunofluorescence and Western blot. RESULT: Nuclear HMGB-1 staining was predominantly located in chondrocytes of both the fibrosis and proliferative zones in healthy TMJ. 1st week and 2nd week after CFA injection, immunoreaction could be detected in the cytoplasms of HMGB-1-positive cells and cartilage matrix especially in hypertrophic zone. At 6th week after CFA injection, cartilage matrix expression was disappeared and the cytoplasm expression of HMGB-1 was very weak in hypertrophic zone. HMGB-1 was translocated from the nucleus to the cytoplasm at 48 h after incubated with IL-1ß (10 ng/ml and 40 ng/ml). The protein level of HMGB-1 was increased after stimulation and had a peak at 48 h. CONCLUSION: HMGB-1 might be associated with TMJ inflammation and OA. Insight into the role of HMGB-1 in TMJ inflammation is helpful to add the new knowledge into the pathogenesis of TMJ OA.

Up-regulation of proteoglycan 4 in temporomandibular osteoarthritic synovial cells by hyaluronic acid.

BACKGROUND: Hyaluronic acid (HA) injection is widely used in the treatment of temporomandibular joint (TMJ) osteoarthritis (OA). Proteoglycan 4 (PRG4) is another joint lubricant that protects surface of articular cartilage. But few studies had explored the role of HA in regulation of PRG4 expression in TMJ OA. In this study, the effects of HA on the expression of PRG4 in osteoarthritic TMJ synovial cells were investigated in hypoxia, which was similar to the TMJ physiologically. METHODS: Synovial cells were isolated from the TMJ OA patients and were treated with or without HA under normoxia or hypoxia for indicated time periods. The proliferation of synovial cells was measured using Cell Counting Kit-8 (CCK-8). The gene expression of HAS2, VEGF, and PRG4 was detected by quantitative real-time PCR, and the secretion of PRG4 and VEGF was assayed by enzyme-linked immunosorbent assay (ELISA). Immunofluorescence was used to examine the protein expression of hypoxia-induced factor-1α (HIF-1α). RESULTS: Hyaluronic acid markedly increased the proliferation of osteoarthritic synovial cells in hypoxia. The expression of HAS2 and PRG4 mRNA of osteoarthritic synovial cells under hypoxia was enhanced by HA treatment. However, HA had no effect on reducing the VEGF and HIF-1α expression in synovial cells in hypoxia. CONCLUSIONS: Hyaluronic acid could promote the expression of HAS2 and PRG4, but could not modulate HIF-1α and VEGF expression of TMJ osteoarthritic synovial cells in hypoxia.

Osteoarthritic changes after superior and inferior joint space injection of hyaluronic acid for the treatment of temporomandibular joint osteoarthritis with anterior disc displacement without reduction: a cone-beam computed tomographic evaluation.

PURPOSE: This study compared the effect of superior and inferior joint space injections of hyaluronic acid (HA) and evaluated osteoarthritic changes in patients diagnosed with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDw/oR) in association with osteoarthritis (OA) by cone-beam computed tomography (CBCT). MATERIALS AND METHODS: One hundred forty-one patients with research diagnostic criteria for ADDw/oR in association with TMJ OA were randomly assigned to 1 of 2 study groups that received superior or inferior joint space injection of HA. CBCT and clinical examination were performed before treatment and at 3 and 9 months after treatment. RESULTS: One hundred twenty-six patients returned for the 3-month evaluations, and 74 returned for the 9-month evaluations. Condylar remodeling and TMJ function showed improvement in most patients after treatment. At 3 months, remodeling scores in the superior and inferior groups were 2.14 ± 3.16 and 4.08 ± 3.82, respectively, and scores were 4.80 ± 3.36 and 7.47 ± 3.90 at 9 months. There were significant differences between the superior and inferior groups at 3 and 9 months after treatment (3-month, P = .002; 9-month, P = .002). The Helkimo index of the inferior group was significantly lower than that of superior group at 3 and 9 months (3-month, P = .008; 9-month, P = .028). There were no significant differences in maximal mouth opening between the 2 groups at 3 and 9 months (3-month, P = .82; 9-month, P = .20). CONCLUSION: Superior and inferior joint space injections of HA are effective methods for the treatment of ADDw/oR in association with TMJ OA. The injection of HA within the inferior joint space appears to result in better condylar reparative remodeling and improvement in jaw function.

Modified condylar distraction osteogenesis via single preauricular incision for treatment of temporomandibular joint ankylosis.

BACKGROUND: Temporomandibular joint (TMJ) ankylosis with facial asymmetry is still controversial to deal with. This study describes a modified condylar distraction osteogenesis protocol via preauricular approach for the treatment of this condition. METHODS: From 2006 to 2013, 18 patients with TMJ ankylosis were enrolled. The Wuhan TMJ Ankylosis treatment protocol includes as follows: (1) preauricular approach is the only surgical access; (2) TMJ arthroplasty is used to recontour the condylar head, and the vertical height of condyle is maintained; (3) distractor placement with distractor port exiting via preauricular incision; (4) distraction after 5 to 7 days of latency period with 0.5 mm twice daily; and (5) distractor removal after 3-month consolidation through preauricular incision. All patients had clinical follow-up and detailed examination. RESULTS: All patients had satisfactory results postoperatively. The mean (range) mouth opening increased from 7.1 (0-18) to 32.1 (28-43) mm during 37 (6-81) months of follow-up period (P < 0.01). Facial asymmetry was corrected in all patients, and all patients had minimal postoperative scar perception of the preauricular incision. CONCLUSIONS: The Wuhan TMJ ankylosis protocol provides a safe and effective treatment alternative in managing TMJ ankylosis, especially in young women who are anxious about perceptive extraoral scar.

Condylar and occlusal changes after high condylectomy and orthodontic treatment for condylar hyperplasia.

Condylar hyperplasia (CH) of human temporomandibular joint (TMJ) often occurs unilaterally, and causes occlusal disturbance and facial asymmetry. The purpose of this study was to compare the effects of high condylectomy with and without postsurgical orthodontic treatment. Forty patients were diagnosed as having active CH and treated with high condylectomy. Patients in group A (n=24) took the postsurgical orthodontic therapy immediately after surgery, and those in group B (n=16) did not take orthodontic therapy. For both groups, the mandibular ramus height on the affected side was decreased significantly after surgery. Orthodontic treatment promoted maxillary alveolar remodeling significantly by depressing alveolar bone of the affected side and increasing alveolar bone of the nonaffected side. Better improvement for facial midline deviations was observed in group A than in group B. In both groups, the condylar remodeling was observed and manifested by the smoothening of condylar surface and returning of condyle to normal position in glenoid fossa. It was concluded that high condylectomy in the treatment of active CH of TMJ improved the functional occlusion and facial aesthetic. Postsurgical orthodontic therapy could more effectively enhance maxillary alveolar and condylar remodeling, and more rapidly and meticulously establish the stable occlusal and normal position of condyle than the spontaneous remodeling.

Triple-layered cell sheet for tissue-engineering the synovial membrane of the temporomandibular joint.

OBJECTIVE: Temporomandibular disorder causes the dysfunction of fibroblast-like synoviocytes (FLSs) which are predominant in the lining layer (LL) of synovial membrane (SM) and responsible for the secretion function of the SM of the temporomandibular joint (TMJ). This study aimed to construct a triple-layered cell sheet (CS) for tissue-engineering the SM. METHODS: FLSs were harvested and identified immunocytochemically. A triple-layered CS was fabricated by an original method of combining type I collagen and FLSs. Staining and a transmission electron microscope were used to compare the morphological similarities between the CS and the natural LL. Hyaluronic acid (HA) production and HA synthase 2 (HAS2) gene expression were assessed by ELISA and PCR, respectively. Transplantation of triple-layered CSs into nude mice was performed and examined by staining and immunohistochemical methods. RESULTS: FLSs expressed vimentin, CD44 and heat shock protein 27. The triple-layered CS possessed a structure similar to natural LL. No tight conjunction was observed between adjacent FLSs. The triple-layered CS secreted HA at a quantity about 3 times that of the single-layered CS. The triple-layered structure induced higher expression of HAS2 in FLSs. No difference in HAS2 expression between the triple-layered CS and natural SM was observed. Multiple-layered FLSs and invasion of host fibroblasts and vessels were observed 2 weeks after transplantation. HAS2 and HA were expressed in surface cells and extracellular matrix, respectively. CONCLUSION: FLSs of the TMJ were type B synoviocytes. The triple-layered CS mimicked natural SM morphologically and functionally. The CS survived for 2 weeks in vivo. Therefore, triple-layered CS might be highly competent for tissue-engineered SM.

Fibroblast growth factor 2 involved in the pathogenesis of synovial chondromatosis of temporomandibular joint.

BACKGROUND: Synovial chondromatosis (SC) of temporomandibular joint (TMJ) is a rare proliferative disorder characterized by the formation of cartilaginous or osteocartilaginous nodules in synovium and joint space. Fibroblast growth factor 2 (FGF-2) is frequently applied in chondrogenic differentiation assays. Therefore, we hypothesized that FGF-2 might involved in the pathogenesis of SC. METHODS: SC synovium and loose bodies (LBs) specimens were observed by histological and immunohistochemical methods. Real-time PCR was conducted for comparing genes expressions in SC and normal synovium. SC synoviocytes were stimulated by FGF-2 in the presence or absence of its antagonist long pentraxin-3 (PTX3) for 6 days. Real-time PCR and alkaline phosphatase (ALP) activity were performed to examine the effects exerted by FGF-2 and PTX3. RESULTS: SC synovium, no matter facing the articular cavity or covering LB, was characterized by increased quantity of synoviocytes and blood vessels. FGF-2 was expressed in chondrocytes and fibroblast-like cells of LBs, and the wall of blood vessels. Expressions of chondrogenic genes (Sox9 and Wnt-4), osteogenic genes (Foxc2), FGF-2, and VEGF-A mRNA were significantly higher in SC synovium than that of the control group. The stimulation of FGF-2 on SC synoviocytes increased ALP activity and expressions of chondrogenic genes (Sox9, Col2α1, and Aggrecan), osteogenic genes (Foxc2, osteocalcin, and Col1α1), and VEGF-A, but PTX3 inhibited these effects. CONCLUSION: FGF-2 was responsible for the formation of cartilaginous loose bodies and involved in the pathogenesis of SC.

Post-condylectomy orthodontic treatment for a severe asymmetrical open bite in a condylar hyperplasia patient.

A satisfactory treatment of an 18-year-old lady was reported with right combination-type condylar hyperplasia (CH) in active phase. The chin severely deviated to the left, with the right gonial angle locating at a lower level. Intraorally, the lower centre line shifted to the left, the scale of which reached the width of one lower incisor. The right molar relation was mesial. Right maxillary second molar over-erupted without contact to lower teeth. There had been 2.5-mm anterior open bite (AOB) before surgery (T1) due to the tongue-spitting habit. After judging the benefits and disadvantages of all treatment alternatives, the decision was made to perform a right condylectomy and post-surgery orthodontics. Before orthodontics (T2) when the chin was positioned centred, an asymmetrical open bite occurred, caused by pre-contact between the right maxillary and mandibular second molars. Meanwhile, the AOB at T2 became 11.5mm. Orthodontic-related treatment included four premolars extraction and intrusion of bilateral maxillary molars using four miniscrews. Finally, this treatment achieved a clinically centred chin with two gonial angles at the same level. Post-condylectomy, the large AOB was resolved, together with a bilateral neutral molar relationship and alignment of the incisor midlines. Besides, the resected right condyle was covered by a continuous cortex bone and returned to the glenoid fossa. In sum, a high-challenging combined-type CH case was accomplished with impressive improvement in facial and occlusal symmetry, thanks to condylectomy and post-surgery miniscrew-assisted orthodontics.

Ankylosis of temporomandibular joint after the traumatic brain injury: a report of two cases.

Mouth opening limitation after the neurosurgical procedures is a common complication and usually resolves within 3 months. If limited mouth opening remains unresolved on the long term, an intra-articular ankylosis of temporomandibular joint may develop eventually. The possible mechanisms base on the myositis and atrophy of the masticatory muscles for these craniotomies are often involved in the temporalis. This article reports two unusual cases with the intra-articular ankylosis of temporomandibular joint after the traumatic brain injury, who received a modified surgical treatment for joint ankylosis. Therefore, the early diagnosis and intervention are important to minimize these complications.

Correction of rabbit model with mandibular ramus shortening by distraction osteogenesis at condylar neck.

PURPOSE: The rabbit model has been established to mimic the effect of temporomandibular joint (TMJ) arthroplasty of ankylosis, and distraction at the level of the condylar neck is used to elongate the ascending ramus. The histomorphologic changes of TMJ and distraction gap were investigated. MATERIALS AND METHODS: The unilateral condyles and articular discs were extirpated, and the experimental mandibular rami were shortened by 5 mm. An embedded distracter was used to restore the height of the mandibular ramus by unilateral condylar neck distraction (0.8 mm daily for 7 days). A total of 12 adult white rabbits were used, 8 in the experimental group and 4 in the control group. Of the 8 rabbits in the experimental group, 4 each were killed at 4 and 8 weeks after completion of distraction. The TMJ and distracted calluses were harvested and processed for radiographic and histologic examination. RESULTS: An open bite was seen in all rabbits postoperatively that had diminished at the end of distraction. The newly formed condyles radiologically showed remodeling, flattening, and sclerosis. The bony transport disc had gradually remodeled to a new condyle that was similar to the original condyle in appearance and structure. The surface of the transport disc was covered with a fibrous tissue. Moreover, the bony regeneration was perfect in the distraction gap. CONCLUSION: These results suggest that distraction osteogenesis at the condylar neck using the traditional preauricular approach of TMJ surgery, without the additional incision, can be performed concurrently with arthroplasty of TMJ ankylosis at the same region.

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. Patient's 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 Helkimo's 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 Helkimo's 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 Helkimo's 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.

Regulation of HAS expression in human synovial lining cells of TMJ by IL-1beta.

Hyaluronan (HA), a major glycosaminoglycan of synovial fluid, is synthesised by a class of membrane-bound HA synthase (HAS) proteins. In the present study, we investigated the regulatory roles of IL-1beta on HAS gene expression and HA production by the fibroblastic synovial lining cells. The synovial lining cells from synovial membrane in human temporomandibular joint (TMJ) were cultured and characterised using immunocytochemistry with CD14, CD44, and vimentin monoclonal antibodies. With or without treatment with IL-1beta, the production of HA was detected with radiometric assay and the expression of HAS mRNAs were analysed with a semi-quantitative reverse transcribed polymerase chain reaction (RT-PCR). HA synthesis was significantly augmented with 1ng/ml of IL-1beta for both 24 and 48h stimulation, however the production of HA declined if stimulated with 10ng/ml of IL-1beta. The expression of HAS2 and 3 mRNA were enhanced about 4.2- and 7.2-fold after 4h stimulation with 1ng/ml of IL-1beta, respectively. From these results, it is concluded that IL-1beta functions on regulating HAS expression and consequently promoting the secretion of HA in synovial lining cells from TMJ.

A hypothetical biological synovial fluid for treatment of temporomandibular joint disease.

Temporomandibular Joint disorder (TMD) is a common disorder of mandibular motion system with distinct clinicopathological characteristics. TMD may cause to change in the components of synovial fluid, that affects the functions on lubrication and nutrition of cartilage. Boundary lubrication system contributing to the low friction of joint consists of three parts: lubricin, surface-active phospholipids and hyaluronan (HA). Diminishment of lubrication function is thereby implicated as an adverse contributing factor in degenerative joint diseases such as internal derangement, osteoarthrosis. Moreover, mesenchymal stem cells (MSCs) of synovial membrane can be obtained without irreversible damage, are easily expandable with limited senescence. We postulate that biological active components secreted from MSCs are separated and accumulated by gel permeation chromatography, and then we use the ultra-flirtation of serum and biologically active components to reconstruct the biological synovial fluid in order to rehabilitate the boundary lubrication system and the nutrition of cartilage. Further study investigating the components of biological synovial fluid provides with new treatment strategy for TMD.