REDUCTION OF COMPOSITE POLYMERIZATION CONTRACTION STRESS

描述(改编自调查者的摘要)：一个宽泛的目标 因为这项建议是为了减少聚合反应产生的应力 通过综合表征树脂复合材料的收缩 其凝胶化行为及对其组分贡献的评价 力学性能和残余应力状态。这将会实现的 通过四个具体目标。第一个是将凝胶后的 聚合收缩应变为总收缩应变。平行 全收缩和凝胶后收缩测量技术的实验将 检验凝胶后与总的比率(凝胶前和凝胶后)的假设 收缩力较低的材料收缩程度较低， O度转换的发展较慢，而O度的发展较慢 僵硬。二是评价胶凝行为和效果 复合材料聚合过程中的刚度动态力学分析 (DMA)将表征复合材料的凝胶行为以进行关联 凝胶后和总收缩数据。这将提供基线 从中修改凝胶的起始值。三是评价方法 用于延缓聚合反应过程中的凝胶化 连续体。光的使用方法和浓度 光敏剂和还原剂将被修改以检验这一假设 因此，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 复合体的属性。第四个目标是发展精准、 聚合收缩的关联数值模型 微观力学方法。减少残余应力的机会将是 通过使用NEW对成员行为进行参数分析进行评估 开发了计算机建模算法。将开发新工具以 用电流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，使聚合物化学的未来进展 固化技术可以根据它们的好处进行评估。临床上 收缩应变和应力将显著降低 这将提高树脂复合材料的性能和使用寿命 修复术。

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.