Development of high performance, caries-inhibiting dental nano-materials

描述（由申请人提供）：继发性龋齿和修复体骨折是更换现有牙齿修复体最常见的原因。替代牙科占所有手术工作的70%，在美国每年花费50亿美元。在初步研究中，首次合成了磷酸钙（Ca-PO4）和氟化钙（CaF2）纳米颗粒，并将其掺入牙科树脂中。本研究的目标是：(1)开发新一代的耐应力、耐蚀纳米复合材料；(2)确定纳米颗粒大小和组成的影响，以及美观的玻璃共填料增强；(3)设计出抑制龋齿能力超过释放电流修复体的纳米复合材料，并设计出与电流承载、不释放复合材料相匹配的长期机械耐久性和耐磨性纳米复合材料；(4)建立纳米复合材料的加工方法和结构性能关系。AIM 1将测试以下假设：(i)减小纳米颗粒尺寸将显著增加释放量，其释放量远高于含有传统Ca-PO4颗粒的对照复合材料；（ii）玻璃增强将提高纳米复合材料的强度、韧性和耐磨性，达到与商业承应力、不释放复合材料相匹配的水平，比目前释放的修复材料好2-3倍。AIM 2将检验以下假设：(i)纳米复合材料的氟化物释放量与CaF2纳米颗粒大小成反比，并与CaF2体积分数成正比；（ii）纳米复合材料的强度和韧性是树脂改性玻璃离聚体对照材料的2-3倍，磨损深度是对照材料的1/3。AIM 3将测试以下假设：(i)抑制龋齿取决于纳米颗粒的大小和组成；（ii）纳米复合材料具有更高的机械性能，可以比目前释放的修复材料更有效地预防龋齿。AIM 4将测试以下假设：(i)对水老化和热循环的机械反应将取决于纳米颗粒的大小和组成；（ii） Ca、PO4和F释放量超过电流释放恢复剂的纳米复合材料，经过2年的水老化和热循环后，其力学性能将与商用不释放应力复合材料相匹配；(3)水老化/热循环后，纳米复合材料的长期离子释放量将超过对照。预期的结果是：(1)新一代的应力承载纳米复合材料，释放高水平的抗蛀牙剂，抑制蛀牙；(2)克服继发性龋齿和修复失败两大问题，对牙科产生重大影响；(3)新的纳米复合材料加工方法、结构-性能关系和模型，可应用于应力承受和控制释放能力都很重要的牙科和骨组织工程。

DESCRIPTION (provided by applicant): Secondary caries and restoration fracture are the most frequent reasons for replacement of existing tooth restorations. Replacement dentistry accounts for 70% of all operative work and costs $5 billion/year in the US. In preliminary studies, nanoparticles of calcium phosphates (Ca-PO4) and calcium fluoride (CaF2) were synthesized for the first time and incorporated into dental resins. The objectives of the proposed research are to: (1) develop a new generation of stress-bearing, caries-inhibiting nancomposites; (2) determine the effects of nanoparticle sizes and compositions, and esthetic glass co-filler reinforcement; (3) design nanocomposites with tooth caries-inhibition capability exceeding current releasing restoratives, and long-term mechanical durability and wear that match current stress-bearing, non-releasing composite; and (4) establish nanocomposite processing methods and structure-performance relationships. AIM 1 will test the hypotheses that: (i) Decreasing the nanoparticle size will significantly increase the release to be much higher than a control composite containing traditional Ca-PO4 particles; (ii) Glass reinforcement will improve the nanocomposite strength, toughness and wear to match commercial stress-bearing, non-releasing composite, and to be 2-3 fold better than current releasing restoratives. AIM 2 will test the hypotheses that: (i) Fluoride release from nanocomposite is inversely proportional to CaF2 nanoparticle size, and is proportional to CaF2 volume fraction; (ii) Nanocomposites will have strength and toughness 2-3 fold greater than a resin-modified glass ionomer control, and wear depth 1/3 that of the control. AIM 3 will test the hypotheses that: (i) Tooth caries inhibition depends on nanoparticle size and composition; (ii) Nanocomposites, with much higher mechanical properties, can prevent tooth caries much more effectively than current releasing restoratives. AIM 4 will test the hypotheses that: (i) Mechanical response to water-aging and thermal-cycling will depend on nanoparticle size and composition; (ii) Nanocomposites, with Ca, PO4 and F release exceeding current releasing restoratives, will possess mechanical properties that match commercial stress-bearing, non-releasing composite, after 2 years of water-aging and thermal cycling; (iii) After water-aging/thermal cycling, nanocomposites will exceed the long-term ion release of the controls. The expected outcomes are: (1) A new generation of stress-bearing nanocomposites with release of high levels of cavity-fighting agents to inhibit tooth caries; (2) Significant impact on dentistry by overcoming the two major problems: secondary caries, and restoration failure; (3) Novel nanocomposite processing methods, structure-property relationships and models, that can be applied to dental and bone tissue engineering where stress-bearing and controlled-release capabilities are both important. PROJECT NARRATIVE: This project, utilizing novel nanoparticles synthesized in our laboratory for the first time, seeks to develop a new generation of stress-bearing, tooth caries-inhibiting nancomposites to overcome secondary caries, which is the major reason for replacement of existing restorations. Replacement dentistry accounts for 70% of all operative work and costs $5 billion/year in the US alone. Furthermore, this project will establish novel nanocomposite processing methods, structure-property relationships and models, which can benefit dental and bone tissue engineering where load-bearing and controlled-release capabilities are both important.