鈣矽生醫陶瓷在牙髓病治療之研發與應用

Abstract

逆向充填、根管穿孔修補以及活髓治療都是臨床牙髓病治療常見的術式；其成功治療的關鍵除了有賴於完全的根管清創外，理想的修補材料扮演舉足輕重的角色。而鈣矽生醫陶瓷材料與市售材料MTA為相同成分系統，具備良好生物相容性與封閉性質，與水調拌後黏稠度適中易於臨床操作，硬化時呈現高pH值且具有一定強度，使用上不需特殊儀器，並且可藉由調整添加成分比例來改變材料的化學與物理性質，在牙髓病修補治療應用上深具潛力。因此本研究以CaO-SiO2成分系統為基礎，研發適合用於牙髓病修補治療的鈣矽生醫陶瓷（CSCs）材料，並從材料水合行為、表面活性層形成機轉、生物相容性三個層面，詳細探討鈣矽生醫陶瓷在牙髓病修補治療應用的潛力。第一章以鈣矽生醫陶瓷之研發與水合行為探討為核心。從SEM顯微結構、XRD晶相分析與FT/IR吸收光譜分析結果證實，鈣矽生醫陶瓷材料M811與市售兩種MTA的水合行為十分相似，由C3S主導其水合反應行為，而C3A與C4AF則可能藉由快速的溶解與再結晶作用形成水合產物，以提供CSH形成之材料結構骨架與成核中心的方式，而有助於CSCs整體的水合反應進行。第二章則著重鈣矽生醫陶瓷表面活性鈣磷化合物形成機轉的研究。SEM觀察到M811表面反應結晶類似HAP的顯微結構，經SEM-EDS鑑定為Ca/P 1.57之Ca-P rich的活性反應層，而XRD分析發現低結晶性HAP的繞射峰出現，FT-IR顯示CO3-for-PO4 Apatite的吸收光譜，同時ICP-OES檢測到環境磷離子大量被消耗，綜合這些研究結果證實「M811鈣矽生醫陶瓷於模擬體液環境，於材料表面形成鈣磷化合物的生物活性層」的假說，顯示本研究所研發之M811具備生物活性材料的性質。第三章則建立活髓材料之生物相容性測試模型，以研究鈣矽生醫陶瓷之生物相容性表現為主軸。細胞貼附行為觀察與細胞存活率分析結果一致，證實鈣矽生醫陶瓷具有良好的生物相容性。總結本研究的結果，M811與市售MTA有相似的水合行為，暗示可能與MTA同樣具有良好之封閉能力；同時於SBF環境中具有形成表面活性HCA的能力，且生物相容性良好，為一具有潛力應用於牙髓病修補治療之材料。

Retrograde filling, perforation repair and vital pulp therapy are the common treatment strategies used in endodontics. The success of treatments depends on the adequate debridement of the pulp chamber and root canal system as well as the hermetic sealing obtained by an ideal restorative material. Calcium silicate bioceramics (CSCs), similar to the commercialized MTA in compositions, are potential materials for endodontic restorative treatments. It solidifies into a hard structure with high pH upon hydration. Recrystallization of CSCs may seal the pathways of communication between the canal system and its outer surface. CSCs also have the advantage of good handling properties. In this study, we developed a novel CSC for endodontic restorative treatments based on the CaO-SiOB2 Bsystem. We further investigated various material properties, including hydration behavior, surface bioactivity and perspectives for biocompatibility. Chapter 1 is dedicated to the development of a novel CSC and the investigations of its hydration mechanism. Utilizing SEM, XRD and FT/IR, we found the novel CSC, M811, and commercialized MTA shared the same hydration mechanism, in which CB3BS is the main contributor to the hydrated structure, catalyzing the production of the hydrates of CB3BA and CB4BAF, which in turn act as nucleation sites for CSH. Chapter 2 focused on the mechanism involved in the formation of bioactive apatite-like surfaces on CSCs in SBF. The apatite-like microstructure with Ca/P ratio of 1.57 was observed using SEM-EDS and the pattern of COB3B-for-POB4 Bapatite was identified by XRD and FT/IR. ICP-OES detected the loss of phosphorus in SBF. Based on these findings, the hypothesis that M811 may form the bioactive apatite-like layer on its surface in SBF was proved. Chapter 3 is to evaluate the biocompatibility for CSCs using MRPC-1 odontoblast-like cells. The results revealed that M811 demonstrated favorite cell adhesion and high cell viability as well as commercialized MTA. We also found that the C3S played the crucial role for the biocompatibility of CSCs. Notably, M811 revealed the similar hydration behavior to commercialized MTA which implies similar and comparable sealing capabilities in M811. Combine with the ability to form bioactive apatite-like layer on its surface in SBF, and its high biocompatibility, M811 is a potential material for restorative endodontic uses.