BACKGROUND: Prefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method. METHODS: We established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded. RESULTS: The deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively. CONCLUSION: The prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.
Finite Element Analysis , Orthodontic Appliance Design , Humans , Myofunctional Therapy/instrumentation , Myofunctional Therapy/methods , Bite Force , Imaging, Three-Dimensional/methods , Overbite/therapy , Stress, Mechanical , Mandible , Incisor , Biomechanical Phenomena
<p><b>OBJECTIVE</b>To isolate the bibenzyl derivatives from the tuber of Arundina graminifolia and evaluate the anti-tumor activity of these compounds in vitro.</p><p><b>METHOD</b>The constituents have been extracted by 95% alcohol and then isolated by column chromatography on silica gel and Sephedax LH-20. The structures were determined by UV, IR, NMR and MS spectral analysis.</p><p><b>RESULT</b>Six constituents have been isolated, and their structures have been established as 2,7-dihydroxy-1-(p-hydroxylbenzyl)-4-methoxy-9, 10-dihydrophenanthrene (1), 4,7-dihydroxy-1- (p-hydroxylbenzyl)-2-methoxy-9,10-dihydrophenanthrene (2), 3, 3'-dihydroxy-5-methoxybibenzyl (3), (2E) -2- propenoic acid-3-(4-hydroxy-3-methoxyphenyl) -tetracosyl ester (4), (2E) -2-propenoic acid-3- (4-hydroxy-3- methoxyphenyl) -pentacosyl ester (5) and pentadecyl acid (6), respectively.</p><p><b>CONCLUSION</b>All compounds except for 3 were isolated from the tuber of A. graminifolia for the first time. Compound 3 with bibenzyl ring opening exhibits stronger anti-tumor activity than that of compounds 1 and 2 with bibenzyl ring closing.</p>
Humans , Antineoplastic Agents , Chemistry , Pharmacology , Bibenzyls , Chemistry , Allergy and Immunology , Cell Line, Tumor , Drugs, Chinese Herbal , Chemistry , Pharmacology , Magnetic Resonance Spectroscopy , Orchidaceae , Chemistry
Objective:To study the determination method of scutellarin in BREVISCAPINE INJECTION using HPLC.Methods:The waters ODS C 18 column (5?m,3.9?150mm) was used. The methanol water glacial acetic acid (40∶60∶1) was used as a mobile phase. The detection wavelength of scutellarin was set at 335nm and internal standard baicalin at 280nm. The resolution of scutellarin's and baicalin peaks was at least 5. Number of theoretical plates of column is no less than 1000 to scutellarin. Results:The recovery of additive sample is 99.8%. RSD is no more 2.0%.Conclusion: It is generally in agreement with external standard method.
