TAILORED COPOLYMERS AS ADVANCED DENTAL RESTORATIONS

对最先进的牙科修复复合材料前体进行了改良， BIS-GMA与陶瓷粉末填料混合的版本开发了25年 前 牙科修复材料的革命性进步 来自于对这项技术的进一步改进。 它必须来自 完全不同的方法来配制复合材料前体。 到 要成为革命性的，新材料必须：（1）易于加工，（2） 单相（无填料），（3）提供优异的粘附性， 牙本质和羟基磷灰石，（4）提供高韧性，（5）表现出 在固化过程中几乎没有或没有收缩，（6）提供等同或改进的 耐磨性和（7）在暴露于唾液时不降解。 液晶（LC）/无机共聚物提供了以下机会： 牙科修复复合材料领域的革命性变化 前体 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，优异的长期热，光化学和氧化 稳定 无机组分倍半硅氧烷，-[RSiO1.5]x-， 低聚物对许多不同的表面提供增强的粘附性， 在超过400摄氏度的温度下氧化和热稳定 并且，当R-RO-时，它们在暴露于湿气时形成二氧化硅颗粒 从而在原位产生新位置所需的耐磨性 用于粘附。 拟议的研究计划从合成开始， LC[RSiO1.5]共聚物的表征，进行体外 评价共聚物的物理和化学性能，然后 在这些属性的初步研究中达到高潮， 合适的环境。 合成的目标是制备低粘度的LC/[RSiO1.5] co. 大分子单体作为复合材料前体。 综合研究将首先 重点介绍了简单单体和二聚体LC的制备， 具有烯属封端的倍半硅氧烷模型化合物。 基线 聚合、粘合和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的 复杂的LC二聚体、三聚体和更高级的低聚物和倍半硅氧烷 系统. LC/[RSiO1.5]共聚大分子单体的形成将开始于 二轮 避免使用烯属官能团用于 使用倍半硅氧烷缩合反应的复合交联 将开始。 第三轮研究将包括栓系掩蔽二氧化硅 一些共聚大分子单体中的颗粒。 机械性能和长期 稳定性研究将遵循更复杂的 共聚大分子单体。 计划在所有阶段进行迭代研究， research. 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.