Department of Mechanical and Aerospace Engineering, University of Missouri-Columbia, Columbia, MO 65211, USA.
Biomed Mater. 2012 Aug;7(4):045014. doi: 10.1088/1748-6041/7/4/045014. Epub 2012 Jun 12.
The purpose of this research was to investigate the influence of the glyoxylic acid (GA) modification of hydroxyapatite (HAP) nanofibers on their dispersion in bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental composites and also to investigate the mechanical properties, water absorption and water solubility of the resulting dental resins and composites. Scanning/transmission electron microscopy images showed that microsized HAP nanofiber bundles could be effectively broken down into individual HAP nanofibers with an average length of ∼15 µm after the surface modification process. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and thermal gravimetric analysis characterization confirmed that GA was chemically grafted on the HAP nanofiber surface, hypothetically by reacting with the amine group on the HAP nanofiber surface. The enhanced dispersion of HAP nanofibers in the dental matrix led to increased biaxial flexural strength (BFS) compared with the corresponding dental resins and composites filled with untreated HAP nanofibers. In addition, impregnation of small mass fractions of the GA-modified HAP nanofibers into the BisGMA/TEGDMA dental resins (5 wt%, 10 wt%) or composites (2 wt%, 3 wt%) could also substantially improve the BFS in comparison with the controls (pure resins or dental composites filled with silica particles alone). Larger mass fractions could not increase the mechanical property further or even degraded the BFS values. Water behavior testing results indicated that the addition of the GA-modified HAP nanofibers resulted in higher water absorption and water solubility values, which are not preferred for clinical application. In summary, well-dispersed HAP nanofibers and their dental composites with enhanced mechanical properties have been successfully fabricated, but the water absorption and water solubility of such dental composites need to be further improved.
本研究旨在探讨乙二醛酸（GA）修饰羟磷灰石（HAP）纳米纤维对其在双酚 A 缩水甘油甲基丙烯酸酯（BisGMA）/三乙二醇二甲基丙烯酸酯（TEGDMA）牙科复合材料中分散性的影响，并研究所得牙科树脂和复合材料的机械性能、吸水率和水溶性。扫描/透射电子显微镜图像显示，经过表面修饰过程，微米级的 HAP 纳米纤维束可以有效地被分解成平均长度约为 15μm 的单个 HAP 纳米纤维。傅里叶变换红外光谱、X 射线光电子能谱和热重分析表明，GA 被化学接枝到 HAP 纳米纤维表面，假设是通过与 HAP 纳米纤维表面的氨基反应。HAP 纳米纤维在牙科基质中的分散性增强，导致双轴弯曲强度（BFS）与未处理的 HAP 纳米纤维填充的相应牙科树脂和复合材料相比有所提高。此外，将少量质量分数的 GA 修饰的 HAP 纳米纤维（5wt%，10wt%）或复合材料（2wt%，3wt%）浸渍到 BisGMA/TEGDMA 牙科树脂中，与对照组（纯树脂或单独填充二氧化硅颗粒的牙科复合材料）相比，也可以显著提高 BFS。更大的质量分数不能进一步提高机械性能，甚至会降低 BFS 值。水行为测试结果表明，添加 GA 修饰的 HAP 纳米纤维会导致吸水率和水溶性值升高，这不利于临床应用。综上所述，成功制备了具有增强机械性能的分散良好的 HAP 纳米纤维及其牙科复合材料，但需要进一步提高此类牙科复合材料的吸水率和水溶性。
