TAILORED COPOLYMERS AS ADVANCED DENTAL RESTORATIONS

最新的牙科修复复合材料前驱体被改性 BIS-GMA陶瓷粉末填充剂共混25年 那是以前的事了。修复性牙科材料的革命性进展不会 来自于对这项技术的进一步改进。它一定来自于 配制复合前体的完全不同的方法。至 作为革命性的，新材料必须：(1)易于加工，(2) 为单相(无填料)，(3)提供特殊的粘附性 牙本质和羟基磷灰石，(4)提供高韧性，(5)展示 在固化过程中很少或没有收缩，(6)提供相同或改善的性能 耐磨性和，(7)接触唾液不会降级。 液晶(LC)/无机共聚物为 牙科修复复合材料领域的革命性变化 先驱物。这些聚合物的LC组分提供韧性， 可加工性(低粘度)，聚合过程中的低收缩， 低CTE，良好的长期热稳定性、光化学性和氧化性 稳定性。无机组分倍半硅氧烷，-[RSiO1.5]x-， 低聚物增强了对许多不同表面的粘附性， 在超过400摄氏度的温度下具有氧化和热稳定性 而且，当R-RO-时，它们暴露在潮湿中形成二氧化硅颗粒 因此，在现场创造了新场地所需的耐磨性 用于粘合。 建议的研究方案从综合和 LC[RSiO1.5]共聚物的体外表征 共聚物化性能的评价 在更多关于这些特性的初步研究中达到高潮 适当的环境。 合成目标是制备一种低粘度的LC/[RSiO1.5]共聚物。 大分子单体作为复合前驱体。综合研究将首先 重点研究了简单单体和二聚体的制备 含烷基帽的硅烷模型化合物。基线 聚合、粘合及聚合物复合材料表征研究 这些第一轮化合物将指导开发更多 复杂的LC二聚体、三聚体和高级齐聚物以及倍半硅氧烷 系统。LC/[RSiO1.5]共大分子单体的形成将在 第二轮。努力避免使用碱性官能团用于 倍半硅氧烷缩合反应合成交联剂 将会开始。第三轮研究将包括系留掩膜二氧化硅 一些共聚大单体中的颗粒。力学行为与长期 稳定性研究将跟随着更复杂的发展 共大单体。在所有阶段都计划进行迭代研究 研究。标准化学、光谱和物理 在适用的情况下，将使用表征方法。

State-of-the-art dental restorative composite precursors are modified versions of BIS-GMA mixed with ceramic powder fillers developed 25 years ago. Revolutionary advances in restorative dental materials will not come from further modifications of this technology. It must come from completely different approaches to formulating composite precursors. To be revolutionary, the new materials must: (1) be easily processable, (2) be single phase (without filler), (3) offer exceptional adhesion to dentin and hydroxyapatite, (4) provide high toughness, (5) exhibit little or no shrinkage during curing, (6) offer equal or improved abrasion resistance and, (7) not degrade on exposure to saliva. Liquid crystalline (LC)/inorganic copolymers offer the opportunity for revolutionary changes in the field of dental restorative composite precursors. The LC component of these polymers provides toughness, processability (low viscosities), low shrinkage during polymerization, low CTE, excellent long term thermal, photochemical and oxidative stability. The inorganic component, silsesquioxane, -[RSiO1.5]x-, oligomers offer enhanced adhesion to many diverse surfaces, are oxidatively and thermally stable to temperatures exceeding 400 degree C and, when R - RO- they form silica particles upon exposure to moisture thus creating, in situ, the necessary abrasion resistance of new sites for adhesion. The proposed research program begins with the synthesis and characterization of LC[RSiO1.5] copolymers, proceeds to in-vitro evaluation of copolymer physical and chemical properties and then culminates in preliminary studies of these properties in more appropriate environments. The synthesis goal is to prepare a low viscosity LC/[RSiO1.5] co- macromonomer as a composite precursor. Synthesis studies will first focus on the preparation of simple monomer and dimer LC and silisesquioxane model compounds with alkenic caps. Baseline polymerization, adhesion and polymer composite characterization studies of these first round compounds will guide development of more sophisticated LC dimers, trimers and higher oligomers and silsesquioxane systems. Formation of LC/[RSiO1.5] co-macromonomers will begin in the second round. Efforts to escape the use of alkenic functionalities for composite crosslinking by use of silsesquioxane condensation reactions will begin. Third round studies will incorporate tethered-masked silica particles in some co-macromonomers. Mechanical behavior and long term stability studies will follow the development of the more sophisticated co-macromonomers. Iterative studies are planned in all phases of the research. Standard chemical, spectroscopic and physical characterization methods will be used where applicable.