| Abstract: | 本研究的目的是評估新型鈣矽為基底的骨水泥材料在迷你豬體內的成骨性，與市售商品進行比較，並且找出更適合臨床應用的骨充填材料。實驗材料包含新開發的矽酸鈣-明膠骨水泥（CSG）、矽酸鈣骨水泥（CS）和市售商品硫酸鈣半水合物骨水泥（CSH），依序進行物理化學特性以及體外和體內成骨作用的檢驗與觀察。在物理及化學特性方面除了相組成和微觀結構以外，也檢測三種骨水泥的耐沖刷性、凝固時間和徑向拉伸強度。接著使用三種細胞株分別為巨噬細胞（RAW 264.7）、人類骨肉瘤細胞株（MG 63）和人類間質幹細胞株（hMSCs）進行細胞生長、分化和礦化的體外細胞實驗，以評估骨水泥對於成骨細胞及破骨細胞的影響。最後使用迷你豬的下顎齒槽骨模型來評估骨水泥在生物體內的降解與骨生成率，在拔牙後三個月的無牙?植入三種骨水泥，並分別於植入後的第六和十二週進行組織學和組織形態學評估。
物性化性實驗結果表示CS和CSG粉末主要由結晶性較差的β-二矽酸鈣組成，不規則的CSH粉末則具有高結晶相。水合硬化後，CS和CSG為水合矽酸鈣凝膠，而CSH表現出板狀石膏晶體結構。 CS、CSG及CSH的硬化時間分別為19、35和10分鐘；CS的抗拉強度從2.4 MPa提升到CSG 3.4 MPa；CSG具抗沖刷性而CSH則無耐沖刷性，其強度為7.6 MPa。沖刷分數分別為CSG組（1.0±0）明顯低於CS組（2.8±0.8）組和CSH組（3.6±0.5）（p<0.05）。可見添加高分子明膠能有效延長骨水泥硬化時間，同時可有效改善抗沖刷性以及增加逕向拉伸強度。
細胞研究結果顯示MG 63和hMSCs細胞在CSG骨水泥表面的成骨活性都顯著高於CSH骨水泥表面，而巨噬細胞活性則在CSH骨水泥表現出較高活性，表示出鈣矽骨水泥有良好的成骨活性且有抑制破骨細胞活性的傾向。進一步的Micro-CT分析及組織學切片影像皆可見鈣矽骨水泥在六周後已完全降解，添加明膠可有效減緩骨水泥降解。植入十二週後，CS組的骨生成體積百分比略高於CSG和CSH組，同時可見三組骨水泥皆已完全降解。結果顯示CSG骨水泥具有較佳的抗沖刷性，在體內和體外均具有良好的成骨作用，推測其具有臨床應用的潛能，但仍須進一步的動物實驗來驗證。
The purpose of this study was to evaluate the physicochemical properties and the in vitro and in vivo osteogenesis of the newly developed calcium silicate containing 5 wt% gelatin (CSG) cement compared with calcium silicate (CS) and calcium sulfate hemihydrate (CSH) cements. In addition to the phase composition and microstructure, washout resistance, setting time, and diametral tensile strength of the bone cements were also performed. In vitro examination of cell growth, differentiation, and mineralization were performed with macrophage cell line (RAW 264.7), MG 63 human osteoblast-like cells, and human mesenchymal stem cells (hMSCs). The mini-pig model with mandibular alveolar bone defect was used to assess the in vivo function of cement.
Histological and histomorphometric assessments were performed at 6 and 12 weeks after implantation. The results indicated that the CS and CSG powders were mainly composed of poorly crystalline β-dicalcium silicate, and the irregular CSH powders had a highly crystalline phase. After setting, the product of CS and CSG was calcium-silicate-hydrate gel and CSH exhibited a plate-like gypsum crystal structure. The setting time of CS, CSG, and CSH was 19, 35, and 10 min, respectively. Gelatin effectively improved the washout resistance and diametral tensile strength of CS from 2.4 MPa to 3.4 MPa, while CSH had no washout resistance and its strength was 7.6 MPa. The osteogenic activity of MG 63 and hMSCs cells on the CSG cement surface was consistently shown to be significantly higher than that on the CSH cement surface. Interestingly, CS and CSG cements exhibited lower macrophage expression compared to CSH cements. Twelve weeks after implantation, the amount of new bone in the defect area of the CS group was slightly higher than that of the CSG and CSH groups. It is concluded that CSG cement had improved anti-washout performance, favorable osteogenesis in vitro and in vivo, which was beneficial for clinical application. |
