- 學位論文
人類牙周膜韌帶力學行為之探討
Investigation of biomechanical behaviors of natural human tooth periodontal ligament
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摘要
背景與目的： 牙周膜韌帶(Periodontal Ligament, PDL)的力學行為在牙醫學非常重要，提供緩衝機制免於牙齒在受力時斷裂；反之當承受不當力量，例如設計不良的補綴物，會造成嚴重發炎。更有甚者，牙科植體應用在牙科治療上與日俱增，主要的後遺症為周圍齒槽骨喪失，其肇因於植體受力後缺乏緩衝設計，因此了解牙周膜韌帶的力學行為為當務之急。 研究方法： 本研究計畫以有限元素計算力學方法，推算牙周膜材料參數，建立可靠數學模型；在實驗方面設計更精良的測量裝置，以非侵入式檢測，取得牙周膜受力的受力位移數據資料。 實驗結果： 在數學模擬方面，較諸非線性應變能模型，本研究發現線性張力─壓力體積粘彈模型更能精準模擬健康牙周膜韌帶的受力反應，而偏切粘彈模型則提供損傷牙周膜韌帶之應力分佈模擬；在牙周膜韌帶測量裝置的研發方面，我們的新型裝置可取得潛變、應力鬆弛、能量耗損、阻尼制振的粘彈數據。 結論： 本研究提出張力─壓力體積粘彈模型，可精準符合牙周膜韌帶受力、卸力的實驗數據，提供實時觀察的可靠模擬；所研發的受力位移測量裝置呈現良好的一致性與再現性，觀察到大約300gw潛變轉折點，大約100gw應力鬆弛瓶頸，1.26x10^-1 mJ及3.30x10^-2 mJ的遲滯環能量損耗，1.30x10^5 (N⋅sec)⁄m的粗略阻尼係數。
並列摘要
Background/Purpose： The mechanical behavior of PDL is very important in dentistry. It provides cushion mechanism to protect tooth from fracture during loading. In contrast, it will make severe inflammation if PDL bearing unsuitable force, for example, from pooly designed prothesis. Moreover, dental implant is well accepted in dental therapy recently. A main side effect, surrounding bone loss, is usually due to lack of cushion design in implant. Thus, understanding the mechanical behavior of PDL is an imperious mission. Methods： This research used finite element method to retrograde calculate the PDL parameters and construct a reliable mathematic model. In experiment, we designed a better device for data acquisition. It provided noninvasive test to collect the loading-displacement data of PDL. Results： Result of this research, compared to nonlinear strain energy model, the linear tension-compression volumetric viscoelastic model could better simulate the mechanical response of normal PDL. The deviatoric viscoelastic model provided the stress distribution simulation of damaged PDL. On the other hand, the latest designed measuring equipment has collected the data about creep, stress relaxation, energy loss and damping tendency. Conclusions： The tension-compression volumetric viscoelastic model, accurately fitting the experimental mechanical data of PDL, provided a reliable simulation for real-time mechanism. The new measuring equipment, presenting well consistency and reproducibility, recorded an about 300gw turning point of creep, an about 100gw primary stress relaxation limit, 1.26x10^-1 mJ and 3.30x10^-2 mJ energy loss in hysteresis loop, and a 1.30x10^5 (N⋅sec)⁄m rough damping coefficient.
參考文獻
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