REDUCTION OF COMPOSITE POLYMERIZATION CONTRACTION STRESS

描述（改编自研究者摘要）：广泛目的 因为该建议是为了减少聚合引起的应力 树脂复合材料的收缩，通过综合表征， 它的凝胶化行为和组分贡献的评价， 机械性能和残余应力状态。 完成这项工作的方法是 四个具体目标。 第一种是将后凝胶 聚合收缩应变与总收缩应变之比。 平行 使用总收缩和凝胶后收缩测量技术的实验将 检验凝胶后与总（凝胶前和凝胶后） 收缩力较低的材料的收缩较低， O转化度的发展较慢， 刚度 二是评价成胶行为和有效性 聚合过程中复合材料刚度动态力学分析 (DMA)将表征复合材料的凝胶化行为， 凝胶后和总收缩数据。 这将提供基线 由此改变凝胶化的开始。 三是评价方法 用于延迟聚合发展中凝胶化的开始 连续体 研究了光照方式和光照浓度对植物生长发育的影响 光敏剂和还原剂将被修改以检验假设 可以通过改变光引发过程来延迟凝胶化 减少收缩和残余应力，而不牺牲物理性能 复合材料的性能。 第四个目标是发展准确、 聚合收缩的相关数值模型， 微观力学方法 减少残余应力的机会将是 通过使用新的成分行为的参数分析进行评估 开发了计算机建模算法。 将开发新的工具， 评估当前牙科复合材料系统中的残余应力， 放置和固化方法，使未来的进展，在聚合物化学 并且可以评估固化技术的益处。 临床 将产生收缩应变和应力的显著减小 这将提高树脂复合材料的功能和寿命 道歉

DESCRIPTION (adapted from the Investigator's abstract): A broad objective for this proposal is to reduce stress resulting from polymerization shrinkage in resin composites through a comprehensive characterization of its gelation behavior and evaluation of constituent contributions to its mechanical properties and residual stress state. This will be achieved through four specific aims. The first is to correlate post-gel polymerization contraction strain to total contraction strain. Parallel experiments with total and post-gel contraction measurement techniques will test the hypothesis that the ratio of post-gel to total (pre- and post-gel) contraction is lower in materials that exhibit lower contraction force, slower development of degree o conversion, and slower development of stiffness. The second is to evaluate gelation behavior and effective stiffness for composites during polymerization Dynamic mechanical analysis (DMA) will characterize the gelation behavior of composites for correlation with post-gel and total contraction data. This will provide the baseline from which to modify onset of gelation. The third is to evaluate methods for delaying the onset of gelation in the polymerization development continuum. The method of light application and the concentration o photosensitizer and reducing agent will be modified to test the hypothesis tha gelation can be delayed by altering the photoinitiation process thereby reducing shrinkage and residual stress, without sacrificing physical propertie of the composite. The fourth aim is to develop accurate, correlated numerical models of polymerization contraction using a micromechanics approach. Opportunities for reducing residual stress will be evaluated through a parametric analysis of constituent behavior using newly developed computer modeling algorithms. New tools will be developed to assess residual stress in current dental composite systems with current placement and curing methods so that future advances in polymer chemistry and curing techniques can be evaluated for their benefits. Clinically significant reductions in contraction strain and stress will be produced which will improve the function and longevity of resin composite restorations.