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Objective To compare the stress distributions in temporomandibular joint (TMJ) for patients with bilateral anterior disc displacement with reduction (ADDwR) after wearing stabilization splints with two different thicknesses during prolonged clenching by using three-dimensional (3D) finite element methods. Methods The 3D TMJ finite element models were constructed based on CT and MRI image data when the patient was biting in maximum intercuspation (working condition 1), on 3 mm thickness splint (working condition 2) and on 5 mm thickness splint (working condition 3), respectively. The von Mises stresses in the articular cartilages ,the TMJ disc and bilaminar zone under 3 working conditions were evaluated after the maximum jaw-closing forces were applied to the mandible for 60 s. Results The von Mises stress of left TMJ was bigger than that of right TMJ under each working condition. After wearing the 3 mm thickness splint, the disc was not recaptured, the stress was concentrated at the posterior band and bilaminar zone of the disc, and the stress on bilateral TMJ was significantly increased. After wearing the 5 mm thickness splint, the right disc was recaptured, the maximum stress was located at intermediate zone of the disc, and the von Mises stresses of articular cartilages and bilaminar zone were decreased by about 40%. However, the left disc was not recaptured, and the von Mises stresses of glenoid fossa cartilage and bilaminar zone were only slightly decreased by about 6%. Conclusions Different thicknesses of occlusal splints lead to different stresses and stress distribution patterns in TMJ of patients with ADDwR. The 5 mm thickness stabilization splint can reduce the stress of glenoid fossa cartilage and bilaminar zone in ADDwR patients. Disc recapture is helpful for ADDwR patients to relieve TMJ stress. When using stabilization splints for the treatment of ADDwR patients, on the premise of comfort wearing, a thicker splint can achieve more favorable stress distributions.
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Objective@#Based on the nature, location and size of parotid tumor, different incisions were chosen and method of selecting the best cosmetic incision for parotid gland tumor operation would be discussed.@*Methods@#33 cases of parotid benign tumor patients that received by Department of Oral and Maxillofacial surgery of First Affiliated Hospital of Nanchang University during 2015-2017 were included in this study. According to the size of the tumor location, different incisions, mainly pretragal vertical, pretragal crutch and rhytidectomy incision were selected. The facial nerve and the great auricular nerve were protected during the operation. In 1-month and 3-month follow-up, clinical examination of temporary facial paralysis, salivary fistula, especially the cosmetic outcome after the surgery were evaluated.@*Results@#The satisfaction rate of parotid cosmetic incision was significantly higher than that of the traditional group, the incidence of transient facial paralysis, salivary fistula was not statistically significant compared with the traditional incision.@*Conclusions@#According to the location of parotid tumor, we should choose the proper cosmetic incision approach, which is better than the traditional surgical incision.
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Objective@#To study the effect of plumbagin on epithelial-mesenchymal transition (EMT) and underlying mechanisms in human tongue squamous cell carcinoma (TSCC) cells.@*Methods@#Methyl thiazolyl tetrazolium assay was apllied to examine the proliferation inhibition effect and half maximal inhibitory concentration (IC50) of plumbagin (0.1, 1.0, 5.0, 10.0, 20.0 μmol/L) in 12, 24, 48 h in TSCC cells. Transwell assay was used to count the number of transmembrane cells and scratch test was performed to examine cells mobility. The flow cytometry was applied to measure intracellular reactive oxygen species (ROS) level in control group, plumbagin group (1.0 μmol/L, 24 h) and glutathione (GSH)+plumbagin group. The expression of E-cadherin, vimentin, Slug, p38 mitogen activated protein kinases (p38MAPK) and phospho-p38MAPK (p-p38MAPK) proteins were determined by Western blotting. The expression of E-cadherin, vimentin and Slug were detected by Western blotting in control group, plumbagin group, activator combined group (p38MAPK activator+plumbagin) and inhibitor combined group (p38MAPK inhibitor+plumbagin).@*Results@#After the treatment of plumbagin for 12, 24, and 48 h, the IC50 of TSCC cells were 10.3, 3.1, 1.5 μmol/L. After treated by 1.0 μmol/L plumbagin for 24 h, the number of transmembrane cells were significantly reduced ([50±13], P<0.05) in comparison to control group (204±6), as well as the cells mobility ([18.2±2.3]%, P<0.05) in comparison to control group ([49.3±1.2]%). Compared to control group (2.32±0.52), the ROS level was increased in plumbagin group (902.20±10.69), while compared to plumbagin group, the ROS level was reduced in GSH combined group (2.18±0.15). In comparison to control group, the expression of E-cadherin was up-regulated (P<0.05), and vimentin, Slug, p-p38MAPK/p38MAPK were down-regulated in plumbagin group (P<0.05). In comparison to plumbagin group, the expression of E-cadherin was down-regulated (P<0.05), and vimentin, Slug, p-p38MAPK/p38MAPK were up-regulated in GSH combined group (P<0.05). Treatment of cells with p38MAPK activator could decrease the expression of E-cadherin significantly (P<0.05) and increase the expression of vimentin (P<0.05) and Slug (P<0.05) in comparison to plumbagin group. Treatment of cells with p38MAPK inhibitor could increase the expression of E-cadherin significantly (P<0.05) and decrease the expression of vimentin (P<0.05) and Slug (P<0.05) in comparison to plumbagin group.@*Conclusions@#Plumbagin inhibits EMT via ROS/p38MAPK-mediated pathway in human TSCC cells.
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Objective:To explore an improved osteotomy of mandible ascending ramus for the surgical approach to large tumors in parapharyngeal space.Methods:According to the operation of parotid gland, masseter muscle was cut near the border of mandibular angle till subperiosteum dissection to mandibular notch, vertical osteotomy outside mandibular foramen to 1.0 cm under mandibular notch, vertical to posterior border of ascending ramus, tumor was exposed and removed, bone plate was repositioned and fixed with titanium. Results:Tumors were completely removed in this way in 3 patients without complications. Conclusion:This surgical approach is suitable for the surgical removal of parapharyngeal interstitial giantism tumor.