Novel F-releasing Nanocomposite Reinforced by Zirconia Nanofibers

描述(申请人提供)：树脂基牙科复合材料已广泛应用于牙科修复龋齿。但复合材料的寿命可能比汞齐短。临床上导致牙科复合修复体失败的两个主要原因是继发性(复发性)龋病和大块折裂。为了减少继发性龋病，人们一直致力于开发释放防龋剂(F-、Ca~(2+)和PO_4~(3-))的牙科复合材料。目前的释氟牙科复合材料的氟离子释放和补给能力很低。玻璃离子和树脂改性玻璃离子(RMGI)具有较高的氟离子释放率，但强度和断裂韧性较低。尽管近20年来该领域取得了长足的发展，但颗粒填充增强的牙科复合材料，尤其是释放防龋剂的牙科复合材料，其强度和断裂韧性仍然不足。为了克服断裂问题，人们使用玻璃纤维和陶瓷(碳化硅和氮化硅)晶须来提高复合材料的强度和断裂韧性，但这些材料的化学稳定性、美观性和操纵性都不令人满意。这一体外探索性项目的目的是研究利用氧化锆基陶瓷纳米纤维增强氟化牙科复合材料的可行性。假设：(1)氧化锆基陶瓷纳米纤维(100-300 nm)将显著提高复合材料的力学性能和断裂韧性，并提供比粗纤维更好的美观和手感；(2)氧化锆基陶瓷纳米纤维增强的复合材料的化学稳定性明显好于玻璃纤维或Si3N4晶须增强复合材料。本项目的目标包括：(1)利用溶胶-凝胶和反应静电纺丝工艺制备氧化锆基陶瓷的纳米纤维；(2)通过特殊的表面偶联剂处理改善纳米纤维的分散性和纳米纤维-树脂基界面的性能；(3)制备氧化锆纳米纤维增强的释氟复合材料牙科复合材料，并测试其弯曲强度、断裂韧性、耐磨性、颜色和光泽指数以及在水中老化后的化学稳定性。我们预计，新型的氧化锆纳米纤维增强的氟化物释放复合材料将显著提高力学性能，以及高氟化物释放和充电能力。该项目的长期目标是开发一系列纳米纤维增强的牙科修复材料，具有防龋性、良好的美观性和手感以及良好的机械性能。这些改进的牙科材料将减少继发性龋齿，延长修复体的寿命。

DESCRIPTION (provided by applicant): Resin-based dental composites have been widely used in dentistry to restore carious teeth. But composites may have shorter life than amalgams. The two leading causes for the failure of dental composite restorations in clinic are secondary (recurrent) caries and bulk fracture. To reduce secondary caries, research efforts have been directed towards the development of the dental composites that release anti-caries agents (F-, Ca2+ and PO4 3- ions).Current fluoride-releasing dental composites have very low fluoride-releasing and recharge capability. Glass ionomers and resin-modified glass ionomers (RMGI) have high fluoride release but they have low strength and fracture toughness. Despite significant development in this area in past 20 years, dental composites reinforced with particulate fillers, particularly those releasing anti-caries agents, still have inadequate strength and fracture toughness. To overcome the fracture problem, glass fibers and ceramic (SiC and Si3N4) whiskers have been used to improve the strength and fracture toughness of composites, but the chemical stability, esthetics and handling properties of these materials are unsatisfactory. The goal of this in vitro exploratory project is to study the feasibility of using zirconia-based ceramic nanofibers to reinforce fluoride-releasing dental composites. The hypotheses are: (1) zirconia-based ceramic nanofibers (100-300 nm) will significantly increase the mechanical properties and fracture toughness of the composite and provide better aesthetics and handling properties than the coarse fibers; (2) the composite reinforced by zirconia-based ceramic nanofibers will have significantly better chemical stability than glass fibers or Si3N4 whisker-reinforced composites. The aims of this project includes: (1) fabricating nanofibers of zirconia-based ceramics using sol-gel and reactive electrospinning process; (2) improving nanofiber dispersion and nanofiber-resin matrix interfacial properties by treatment with special surface coupling agents; (3) fabricating the zirconia nanofiber-reinforced, fluoride-releasing composites dental composites and testing their flexure strength, fracture toughness, wear resistance, color and gloss indices, and chemical stability after ageing in water. We anticipate that the novel fluoride-releasing composite reinforced by zirconia nanofibers will have significantly improved mechanical properties as well as high fluoride-releasing and recharging capabilities. The long-term goal of this project is to develop a series of nanofiber-reinforced dental restorative materials that have anti-caries efficacy, good aesthetics and handling properties as well as good mechanical properties. These improved dental materials will reduce secondary caries and prolong the life of restorations.