Novel F-releasing Nanocomposite Reinforced by Zirconia Nanofibers

描述（由申请人提供）：树脂基牙科复合材料已广泛用于牙科修复龋齿。但是复合材料的寿命可能比汞合金短。临床上复合材料修复失败的两大主要原因是继发龋和体折。为了减少继发龋，人们一直致力于开发能释放防龋剂（F-、Ca 2+和PO 4 3-离子）的牙科复合材料。玻璃离聚物和树脂改性的玻璃离聚物（RMGI）具有高的氟释放，但它们具有低的强度和断裂韧性。尽管在过去的20年里在这一领域取得了显著的发展，但用颗粒填料增强的牙科复合材料，特别是释放抗龋剂的那些，仍然具有不足的强度和断裂韧性。为了克服断裂问题，已经使用玻璃纤维和陶瓷（SiC和Si 3 N4）晶须来提高复合材料的强度和断裂韧性，但是这些材料的化学稳定性、美学和处理性能不令人满意。本研究的目的是探讨氧化锆陶瓷纳米纤维增强牙科释氟复合材料的可行性。假设是：（1）氧化锆基陶瓷纳米纤维（100-300 nm）将显著提高复合材料的机械性能和断裂韧性，并提供比粗纤维更好的美学和处理性能;（2）由氧化锆基陶瓷纳米纤维增强的复合材料将具有比玻璃纤维或Si 3 N4晶须增强的复合材料显著更好的化学稳定性。本课题的主要研究内容包括：（1）采用溶胶-凝胶法和反应静电纺丝法制备氧化锆基陶瓷纳米纤维，（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与树脂基体的界面性能;（3）制备氧化锆纳米纤维增强、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，由氧化锆纳米纤维增强的新型氟化物释放复合材料将具有显着改善的机械性能以及高的氟化物释放和充电能力。本项目的长期目标是开发一系列纳米纤维增强牙科修复材料，这些材料具有抗龋功效、良好的美学和处理性能以及良好的机械性能。这些改进的牙科材料将减少继发龋并延长牙体的寿命。

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.