| dc.description.abstract | Dental implant after surgical implantation,Osteointegration occurs through the proliferation of bone cells on the surface of the implant, The interface tissue surrounding the implant provides stability, so the key to success after surgery is the degree of osseointegration, which is the stability of the implant. In recent years, this implantation method has been applied to limb amputations. After the amputation implant implantation operation, there are three stages of implant stability detection, which are the initial postoperative stability, the evaluation of the implant stability during rehabilitation, and the regular postoperative implant stability tracking.
The experimental planning is based on the osteoblast proliferation on the surface of the implant during the osseointegration to form the interface tissue to provide conditions for increasing the stability of the implant. This study plans to use epoxy resins with different Young′s coefficients as the interface between the femur and the implant. By not adding epoxy, pure epoxy, and epoxy + 30% glass fiber, corresponding to the three stages of the implant stability test, the bone interface tissue is simulated due to the rigidity change. The resonance frequency trend of the model can be used to evaluate whether the implant is stable State, based on which the finite element model and parameter settings are established.Applying ANSYS® 15.0 finite element analysis to estimate the possible vibration modes and resonance
frequencies. The geometric model of the implant is established with reference to the actual samples and 2D drawings provided by The Osseointegration Group of Australia. SolidWorks® is used to draw 3D files. The surface of the implant was originally a three-dimensional structure. Through the osseointegration process, the bone tissue filled with the three-dimensional structure was firmly connected to the inner wall of the medullary cavity.
Therefore, the three-dimensional surface was simplified to a fixed condition of planar contact when the implant model was established. Reverse engineering laser scanner was used to import, the material properties of each component were established in order by reference, and the model was cut and calculated using free mesh. In this study, epoxy resin was used to simulate the osseointegration interface tissue between the femur and the implant. When the osseointegration process is good, the interface tissue regeneration and remodeling make the femur and the implant tightly joint, and there is no friction between the femur, the implant, and the interface tissue. The finite element model sets the contact conditions of the interface tissue, and combines the two contact surfaces of the femur, the interface tissue, and the implant ; Without adding any interface tissue and its model contact conditions, in order to simulate the initial stability after surgery, bone cells have not yet regenerated and remodeled, and the contact surface between the femur and the implant has sliding and friction behaviors. For the friction state, the friction coefficient is defined as 0.58; because the bottom end of NCUpeg is screwed with the implant, it is regarded as fixed, so the contact surface conditions are set to the combined state. For numerical analysis, refer to the experimental vise clamping method, set the boundary conditions of the structural system to the fixed end of the cantilever beam structure, set the three most prominent positions of the femoral bottom as the fixed support points of the overall structure, perform modal analysis and discuss the resonance set 1-20 sets of modal shape results for review, select the modal shapes that match the experimental device to measure the same X and Y directions, and read the representative resonance frequency threshold value as a record. At the beginning of this study, Osstell®-SmartPeg was used as the magnetic accessory at the top of the implant. However, only high-frequency resonance frequencies were obtained during the experimental
measurement. According to the CAE modal analysis results, the high-frequency resonance frequency was only SmartPeg′s local vibration at the top of the implant. There is no vibration to the sheep bones and implants, which can not reflect the osseointegration status of lower limb implant surgery. This study designed a NCUpeg for lower limb implant detection. The experimental measurement results can obtain the low frequency resonance frequency. The low-frequency resonance frequency of the modal analysis is the displacement and swing of the entire sheep bone and the implant. The resonance frequency value can represent the stability of the lower limb implant implantation. Therefore, NCUpeg was selected as the magnetic accessory for this study. Using 4.0 mm as the segmentation, the analysis results of tissue resonance frequency thresholds of different interfaces were developed to evaluate the tendency of implant stability.
After experimental tests and finite element modal analysis and comparison verification, an NCUpeg is designed for lower limb implant detection. The modal analysis results are used to improve the magnetic accessories necessary for this measurement and prove the feasibility of NCUpeg in the measurement device. In this study, the results of the modal analysis of the resonance frequency data are integrated. If the stability of the implant gradually increases, the natural frequency will gradually increase. Therefore, the handheld detector can measure the tendency of the increase of the stability of the implant by the resonance frequency. | en_US |