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Objective:To investigate the treatment effect of combined forsus appliance on young people's Angel Ⅱ~1 malocclusion. Methods:13 Angel Ⅱ~1 cases during pre-peak or peak period was chosen, treated with combined forsus appliance for an average period of 5.5 months, evaluated treatment effect through cephalometric and cast measurement. Results: All canines and molars have reached class Ⅰ or over-class Ⅰrelations, 13 patients' mandibular retrognathia face have gained significant improvement. Conclusion: The combined forsus appliance can be used in early functional treatment, improve class Ⅱ face type and decrease the difficulty of the second period and enhanced treatment effect.
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Objective:To investigate the effects of different impl an t diameter on stress distribution in implant bone interface. Method: The stress and strain in implant bone interface for implants with di fferent diameter (3.0 mm,3.75 mm and 5.0 mm), and with 1.47 N loading mesiodist ally were analyzed by 3 dimesion finite element analysis method. Re sults:The Von mises stress (MPa)at cervix of the implants with the diameter (mm) of 3.0, 3.75 and 5.0 were 0.807,0.533 and 1.080;the alveolar bone displacement (?m) at the cervix of the implants 0.232,0.163 and,0.111 respe ctively. Conclusion: The implant with 3.75 mm diameter is more suitable for orthodontic anchorage.
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Objective:To establish a 3-dimensional finite element model for implant in molar deprived region of mandible. And to lay basis for precise analysis for the biomechanic characteristics of implant anchorage system. Methods:The cross section outline drawn from the molar deprived region of mandible was input into a computer, and ANSYS 5.5 (Swanson Analysis Systems, Inc. Houston, USA) finite element analysis software was used to perform the finite element modeling of the mandible.Results:The cross section outline of the mandible,imitated by a spline curve was smooth and lifelike. This cross section outline was extruded into a three dimensional model. The three dimensional models of the implant and mandible could be smartly meshed to obtain the finite element model of mechanics. Conclusion: An effective 3-dimensional finite element biomechanical analysis model for implant as orthodontic anchorage was established.
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Objective:To investigate the effects of different shapes of implant on stress distribution in implant-bone interface and to select the most appropriate shape for orthodontic anchorage. Method:3-dimesional finite element analysis method was used to analyze the stress and strain in implant-bone interface of knife-edged threaded, square threaded and smooth type implants.Results: The first,second and third main stress (MPa) of knife-edged threaded implant were 6.67, 1.47 and 0.52 respectively with 7.72 MPa of Von Mises stress;those of square threaded 13.00,2.51,0.57 and 11.8;smooth type 10.50,2.50,0.67 and 12.60,respectively. The variables of alveolar bone at the cervix of knife-edged threaded,square threaded and smooth type implants were (0.11×10-3), （0.13×10-3） and （0.94×10-4) mm respectively. Conclusion: The stress in knife-edged threaded implant-bone interface and alveolar bone deformation at the cervix of the implants is minimal,therefore the implants are more suitable for orthodontic anchorage.
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Objective:To study the effects of recombinant human vascular endothelial growth factor on proliferation and differentiation of rat osteoblasts. Methods: Cell culturing, light microscop, MTT assay and PNPP assay were performed to observe the effects of rhVEGF on proliferation and differentiation of the cells. Results: rhVEGF could stimulate osteoblasts proliferation and differentiation. The maximal effect on proliferation was observed at a concentration of 3.125 ng/ml on the third day. ALP activities in osteoblasts were increased most significantly at a concentration of 12.5 ng/ml. Conclusion: rhVEGF may not only induce angiogenesis to facilitate bone formation, but also stimulate this process in a direct way by inducing proliferation and differentiation of osteoblasts.