研發含聚麩胺酸及明膠之水膠攜帶 TGF-β1之磷酸鈣水泥於活髓治療之研究：材料物理性質、生物活性、生物相容性及動物實驗

Abstract

活髓治療的目的在使牙髓保持活性並形成修復性牙本質，維持牙齒正常生理結構、功能、及牙根發育。活髓治療發展至今在臨床上仍然沒有理想之材料。磷酸鈣骨水泥為一生醫陶瓷材料，在骨科及牙科廣泛應用作為骨缺損的修補材料。然而，磷酸鈣骨水泥於活髓治療的研究中，效果並未優於目前臨床效果最佳的三氧礦化物。因此藉由聚麩胺酸-明膠結合生長因子 TGF-β1 添加至磷酸鈣骨水泥，以研究其誘導牙本質牙髓組織再生的效果。本研究分為四大部分，第一部分為材料物理性質測試，分析包含固化時間、機械性質、降解測試、晶相結構。第二部分為生物相容性分析，以 ISO-10993 標準評估材料之細胞存活率與細胞毒性。第三部分為體外生物活性測試，研究材料對牙髓細胞之促進鈣化生成的效果。第四部份為建立大動物實驗模型，以犬隻評估所研發之生醫材料與市售材料於牙髓組織再生之差異。 研究結果顯示添加聚麩胺酸-明膠不影響磷酸鈣骨水泥隨時間降解及再結晶之生醫陶瓷性質，也不會降低抗壓強度，其初始硬化時間大約五分鐘，最終硬化時間大約九分鐘，符合臨床操作需求。至於生物活性方面，磷酸鈣結合聚麩胺酸-明膠攜帶TGF-β1之生物相容性良好，且體外活性測試發現可較三氧礦化物提早誘導鈣化結節生成，於動物實驗中亦證實可成功誘導完整的牙本質橋生成。 磷酸鈣結合聚麩胺酸-明膠攜帶TGF-β1結合了磷酸鈣的良好物理性質及操作性質、磷酸鈣與聚麩胺酸-明膠的生物相容性，以及充分發揮了TGF-β1促進牙本質在生的優勢，因此磷酸鈣結合聚麩胺酸-明膠攜帶TGF-β1之活髓治療材料的臨床應用，是極具潛力的。

Vital pulp therapy is to preserve the pulp vitality as well as to form the reparative dentin for maintaining the normal physical structures and functions of teeth. After years of research and development of the biomaterials, there is no ideal material for vital pulp therapy. Bioactive calcium phosphate cements (CPCs) have been widely used for repairing bone defects because of their excellent biocompatibility and bioactivity. However, CPCs only demonstrated comparative effect with commercial MTA in studies in vital pulp therapy. In this study we evaluated the alpha-tricalcium phosphate cement (α-TCP) with γ-PGA/ gelatin hydrogel carrying TGF-β1 application on vital pulp therapy. Poly-γ-glumatic acid (γ-PGA) is suitable candidate for drug carrier. And TGF-β1 can induce differentiation of dental pulp cell. The purpose of this study is to evaluate effect of CPC/ hydrogel/ TGF-β1 on pulp-dentin regeneration and vital pulp therapy. We examined the possible intervening effects of hydrogel on the clinical compliance of CPC with assessment of its setting time, compressive strength, degradation, crystallinity, and microscopic structure. Biocompatibility, in vitro bioactivity on cultured human dental pulp cell was evaluated and also animal study was performed to evaluate the ability of CPC/ hydrogel/ TGF-β1 to induce hard tissue formation in vivo. The results showed that the setting time and compressive strength of CPC/ hydrogel exhibited no significant difference compared with CPC. The cell viability and cytotoxicity exhibited no harm to the dental pulp cell and animal study presents this CPC/ hydrogel/ TGF-β1 can induce calcified tissue formation. Based on the results, the developed CPC/ hydrogel/ TGF-β1 has great potential as a material for vital pulp therapy.