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.

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.

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.

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.

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.

Objective: To investigate the manufacturing procedures of personalized miniscrew-assisted rapid palatal expanders (pMARPE) using digital technologies and to evaluate the effect of the expanders when expanding the midpalatal suture of an adult. Methods: Digital technologies were used to make pMARPE, which was used to treat a 21-year-old woman with maxillary transverse deficiency (MTD). The relevant literature on MARPE was reviewed. Results: PMARPE could be manufactured using intraoral digital scanning, computer-aided design and computer-aided manufacturing(CAD/CAM ), and 3D printing technologies. After expansion, the width of the anterior midpalatal suture, posterior midpalatal suture and maxillary skeletal width increased by 3.9 mm, 3.2 mm and 4.7 mm, respectively. There was no significant change in the inclination of maxillary first molars, and the height of alveolar ridge decreased slightly. It could be seen that using digital technologies to manufacture personalized expanders was possible for MARPE , and the initial stability of miniscrews played an important role in the expansion success rate, the increase of molar inclination is composed of many parts, and the decrease of alveolar ridge height may be overestimated due to the measurement method, as shown by a literature review. Conclusion The midpalatal suture of an adult patient with MTD could be expanded by pMARPE. However, the effect of this expander on the inclination of the first molar and alveolar bone height needs to be further studied with a larger sample size.