本研究主要探討在植牙術後骨整合期間，牙科植體與周圍骨組織因骨質差異及由於各類骨缺損產生時，其相應的結構共振頻率變化。研究分兩部分，第一部分以多種人造骨塊模擬臨床上不同植牙部位下顎骨 (包含齒槽骨高度和緻密骨厚度)，並透過非接觸式聲能激振-位移響應實驗，量測植體與骨塊結構的共振頻率、並與有限元素分析結果互相驗證，同時確認數值分析模型的適當性；第二部分以電腦斷層掃描影像建立人類下顎骨有限元素模型，藉此探討植牙術後植體周圍不同骨組織的材料係數及產生多種骨缺損時整體結構的共振頻率。 研究顯示，植在不同緻密骨厚度及垂直高度的牙科植體，結構的共振頻率範圍為6771±4.5到7078±17.3 Hz (近遠心側)、5230±6.3到6119±18.0 Hz (頰舌側)；故使用結構共振頻率判斷植牙術後復原情形不需針對不同植牙部位做診斷指標的改變。此外，模擬結果顯示，在初始穩固度期間，結構共振頻率會因骨整合明顯的上升；在骨整合形成的後期穩固度期間，結構共振頻率會逐漸上升並趨近穩態值；而骨缺損發生時，不只是結構共振頻率會明顯降低，當骨缺損間隙大於3 mm時，其結構共振頻率將維持不變。從研究指出，從植體結構共振頻率的變化可以協助臨床牙醫師辨識骨整合概況，或是骨缺損程度，以便採取後續措施提升植牙成功率。 This study shows how to correlate the material properties of interfacial tissue and the severities of closed bone defects to their corresponding frequencies of dental implantation structure during the osseointegration. The study consists of two parts. First, various artificial bone block models were used to mimic different locations of implantation (consists of different vertical heights and cortical thickness) in clinical, and the structural resonance frequencies (RFs) were measured through acoustic excitation and response displacement pickup. Obtained results were compared with their corresponding, finite element analysis (FEA). Secondly, the human mandible model created using commercial software? Simpleware?^?, which was constructed base on a set of in-vivo dental Computerized Tomography (CT) images of human in order to investigate the bone tissue around the implant and various bone defects corresponding to their structural RF after implantation. The results show that the structural RFs of the three type cortical thickness for all vise fixation heights in mesial-distal (MD) direction ranges from 6771±4.5 to 7078±17.3 Hz, likewise, in the buccal-lingual (BL) direction ranges from 5230±6.3 to 6119±18.0 Hz. Therefore we can use the same index to evaluate the healing condition in different locations of dental implantation. In addition, the FEA results show that the stiffness of interfacial tissue which affects the RF of implant significantly in the primary stability stage. While tissue grows harder with time, the RF of implant rises gradually to steady level. Furthermore, the structural RF decreases with various bone defects. It’s worth noting that the structural RFs are not changed when width defect more than 3 mm. The measuring results show that the RF differences can be identified and applied to evaluate bone defects, as well as osseointegration. The proposed technique is a promising approach to aid dentists in assessing dental implant stability after surgery.
