| 摘要: | 人工植牙已成為目前治療牙齒缺損的主要方式，影響植牙成功因素包括牙根設計、表面處理、骨骼狀況及手術技術等，其中牙根外型設計為臨床重要關鍵因素。透過良好外型設計利於初始鎖入、降低鎖入扭矩、減少熱傷害、提高穩定度、減低牙根邊緣骨吸收情形及強化牙根機械強度等，因此重視牙根外型設計將提高手術成功率。本文主要探討牙根外型(如牙型、錐度與自攻缺口)與骨骼之生物力學行為，且藉由牙根鎖入骨骼之扭矩、牙根與骨骼介面穩定度及牙根對骨骼應力分佈研究進行評估。本研究方法涵蓋生物力學測試、有限元素分析及數學模型分析。實驗結果將作為數值方法之基礎資訊，並探討現有數值方法。在鎖入扭矩研究結果發現自攻缺口有助於降低鎖入扭矩與初始鎖入，且錐狀牙根鎖入扭矩較高及具較佳的穩定度，並發現錐狀牙根頸部周圍骨質變較為緊密，另外錐狀碗狀缺口牙根為最佳設計，具備最高的穩定度。植體與骨骼介面穩定度在有限元素分析研究發現位移量的假設在最終抗拉區域較佳，並指出最大應力指標與穩定度相關性最低，反觀，在最終區域的反作用力為較佳指標。另外針對數學模型研究發現桶狀植體有較佳的預估趨勢，但在錐狀植體及牙型需再進行公式化修改。針對牙根對骨骼應力分佈研究結果發現骨骼最大應力均在第一道螺紋處，且方形牙(p = 0.60 mm)擁有最高的接觸面積及較低應力。Dental Implants have become one of the main treatment modalities for missing teeth. The successful factors include the implant design, the surface treatment, the bone quality, the surgical technique, and so on. Among these factors, the implant design is the dominant clinical factor. It’s easier to do initial insertion, decrease the torque of initial insertion, reduce the thermal injury, increase the stability, reduce the resorption of tooth root, and enhance mechanical strength through a good implant design. Therefore, putting great emphasis on implant design will elevate the successful rate of surgery. This thesis mainly studies the implant-bone mechanical behavior, including the insertion torque, the implant-bone interfaces stability, and stress distribution of marginal bone. The research methods include biomechanical test, finite element analysis, and mathematic model analysis. The experimental results will be the basic information of the numerical methods and compare with the standing numerical methods. In the insertion torque study, flute shape plays a significant role in decreasing the torque of initial insertion and being good for initial insertion. The conical implant has the tighter bony contact at the tail thread. In addition, the conical implant with bowl flutes is the optimal design with the highest stability. In the implant-stability analysis study, the assumed displacement should be within the final pullout regions. In addition, the stress index is the last correlated to the holding power. On the other hand, the reaction force within the final regions is better to be highly correlative with the holding power of the implant than the stress index. For the mathematic model study, the calculated values are quite well to correlate with the difference trend of pullout strength, especially for the cylindrical implants. The thread shape and profile should be formulated by modifying the slippage mechanism at the implant-bone interfaces and simulating the strength change in the squeezed bones. For the stress distribution of marginal bone study, the greatest stress in the surrounding bone was consistently concentrated at the root radii of the first thread. Compare with the other threads, the square thread with a 0.60-mm pitch possessed the optimal contact area and stress values. |
