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。但是复合材料的寿命可能比汞合金短。口腔复合修复体临床失败的两个主要原因是继发性（复发性）龋病和大块骨折。为了减少继发性龋齿，研究人员一直致力于开发能够释放抗龋齿剂（F-， Ca2+和po43 -离子）的牙科复合材料。目前牙用释氟复合材料的释氟能力和充注能力都很低。玻璃离聚体和树脂改性玻璃离聚体（RMGI）具有较高的氟化物释放量，但强度和断裂韧性较低。尽管近20年来在这一领域取得了长足的发展，但以颗粒填料增强的牙科复合材料，特别是那些释放抗龋剂的复合材料，强度和断裂韧性仍然不足。为了克服断裂问题，人们采用了玻璃纤维和陶瓷（SiC和Si3N4）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、美观性和处理性能令人不满意。本体外探索项目的目的是研究氧化锆基陶瓷纳米纤维增强含氟牙科复合材料的可行性。假设：(1)与粗纤维相比，氧化锆基陶瓷纳米纤维（100-300 nm）可以显著提高复合材料的力学性能和断裂韧性，并提供更好的美学和处理性能；(2)氧化锆基陶瓷纳米纤维增强复合材料的化学稳定性明显优于玻璃纤维或氮化硅晶须增强复合材料。本课题的研究目标包括：(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-树脂基体的界面性能；(3)制备氧化锆纳米纤维增强释氟牙科复合材料，测试其抗弯强度、断裂韧性、耐磨性、色泽指标和水中老化后的化学稳定性。我们预计，氧化锆纳米纤维增强的新型释氟复合材料将显著改善其力学性能，并具有较高的释氟和再充电能力。该项目的长期目标是开发一系列具有抗龋功效、美观性和处理性能以及良好机械性能的纳米纤维增强牙齿修复材料。这些改良的牙齿材料可以减少继发性龋齿，延长修复体的使用寿命。

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.