| 摘要: | 牙科植體經由手術植入後，藉由骨細胞增生於植體表面產生骨整合現象，由包覆於植體周圍的介面組織提供穩固度，因此手術後成功與否的關鍵在於骨整合程度，即為植體穩固度。近年來此植體植入方法應用於肢體截肢。截肢植體植術手術後，植體穩固度檢測有三個階段，分別為術後初始穩固度、復健過程中植體穩固度評估、及術後定期植體穩固度追蹤等。
實驗規劃基於骨整合期間，植體表面增生的骨細胞構成介面組織，提供植體穩固度增加條件，本研究規劃不同楊氏係數之環氧樹脂作為股骨與植體間介面組織，以不添加epoxy、純 epoxy 及 epoxy+30%玻璃纖維，分別對應植體穩固度檢測的三個階段，模擬骨界面組織因剛性改變，可由檢測模型之共振頻率趨勢，評估植入物是否達到穩固狀態，據此建立有限元素模型及參數設定。應用 ANSYS® 15.0 有限元素分析預估可能產生之振動模式與共振頻率，植體幾何模型建立參照澳洲骨整合團隊所提供實際樣品及2D圖面，使用 SolidWorks® 繪製 3D 檔案，植體表面原呈立體結構處通過骨整合過程，骨組織充滿立體結構之空隙與髓腔內壁牢牢接合，故建立植體模型時將立體表面簡化為平面接觸之固定條件，羊骨模型則採用逆向工程雷射掃描器匯入，參考文獻依序建立各部件材質特性，並使用自由網格將模型切割運算。
本研究使用環氧樹脂模擬股骨與植體間骨整合介面組織，當骨整合過程良好介面組織再生與重塑現象使股骨與植體緊密接合，股骨、植體與介面組織接觸面上不存在摩擦現象，有限元素模型在介面組織接觸條件設定，將股骨、介面組織與植體兩處接觸面設為結合(Bonded)狀態；而在不添加任何介面組織其模型接觸條件，為模擬術後初始穩固度，骨細胞尚未產生再生與重塑現象，股骨與植體間接觸面存在滑動及摩擦行為，本研
究將表面接觸設定為摩擦狀態其摩擦係數定義為 0.58；因 NCUpeg 底端有螺牙與植體旋，視為固定故將接觸面條件設為結合狀態。
數值分析時參照實驗虎鉗夾持方式，設定結構系統邊界條件同懸臂樑結構之固定端，設將股骨底部最突出三處位置，設定為整體結構固定(Fixed Support)支撐點，進行模態分析並討論共振頻率之振型(Mode Shape)，設定 1-20 組模態振型結果做檢視，選取符合實驗裝置測量 X、Y 方向相同之模態振型，讀取所代表之共振頻率值作為紀錄，本研究
初期沿用 Osstell®-SmartPeg 作為植體頂端磁性配件，但於實驗測量時僅可得高頻共振頻率，在 CAE 模態分析結果高頻共振頻率僅為 SmartPeg 於植體頂端局部振動，並無激振至羊骨與植體，無法反映下肢植體手術後骨整合情況，本研究設計一款 NCUpeg 用於下肢植體檢測，於實驗測量結果可得低頻共振頻率，模態分析其低頻共振頻率為整隻羊骨
及植體之位移擺動，其共振頻率值可代表下肢植體植入穩固程度，故選用 NCUpeg 作為本研究之磁性配件，依據收斂分析結果將元素大選用小 4.0 mm 作為分割，展開不同介面組織共振頻率值分析結果，評估植體穩固度之趨勢。
經過實驗測試與有限元素模態分析比較驗證，設計一款 NCUpeg 用於下肢植體檢測，經由模態分析結果改良此測量時必需使用之磁性配件，並證明 NCUpeg 於測量裝置之可行性。本研究綜合模態分析共振頻率數據統整結果，若植體穩固度逐漸增加其自然頻率也會逐漸升高，故手持式檢測儀可由測量共振頻率來判斷植體穩固度逐漸增加之趨勢。
;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. |
