Novel Joining and Interfacial Fracture Mechanics

描述：（由申请人提供）美学陶瓷基装饰的全部潜力尚未实现。成形引起的损伤，在正常咀嚼过程中的疲劳损伤加剧，大大降低了它们的初始强度。由于剩余强度下降到接近 对于咬合力，磨牙牙冠的临床成功率令人失望并不奇怪。全陶瓷后桥在5-10年内具有可接受的成功率仍然是一个梦想。牙冠的生存是材料、制造、设计和服务变量之间一系列复杂的相互作用。 在第一阶段，我们的团队对推荐用于后牙冠的材料的损伤起始和累积有了基本的了解。在整体材料中，微观结构、疲劳和加工参数对损伤的影响已经被表征。通过对这些材料进行分层，可以满足对强度和美学的冲突要求。通过合理的设计，可以管理不可避免的损坏，产生一个损伤容限结构，可以承受层内的微裂纹，而不牺牲系统的结构完整性。我们修订提案的总体目标是从根本上了解损害的引发， 在全瓷牙冠中的累积作为材料、牙冠设计和制造变量的函数。我们实现这一目标的总体方法是从正常轴向载荷下的简单平层结构系统地进展到复杂载荷下的牙冠几何形状，在所有阶段使用临床相关材料。最后， 安装在假骨-PDL系统中的牙齿将在潮湿环境中经受典型的循环咬合载荷。我们的“可交付成果”是（1）指导新材料开发的设计规范和（2）对损伤引发、传播和累积的基本理解，最终形成用于预测新材料、牙体预备设计和牙冠设计组合的临床行为的稳健模型。有了这些成果，将有可能首次使用基本材料特性来准确预测新材料的应用性能。 为实现这些目标的研究分为四个项目：（1）损伤模式和失效机制，（2）复杂载荷、冠几何形状和性能，（3）新型连接方法和界面断裂力学，以及（4）牙齿上层状陶瓷冠的疲劳性能。科学工作将得到两个核心的补充和支持：（1）统计和数据分析核心和（2）整合和管理核心。

DESCRIPTION: (provided by applicant) The full potential of esthetic ceramic-based restorations cannot yet be realized. Shaping-induced damage, exacerbated by fatigue damage during normal chewing, dramatically reduces their initial strength. Since residual strengths fall to values close to occlusal forces, it is not surprising that clinical success of molar crowns has been disappointing. All-ceramic posterior bridges with acceptable success rates over 5-10 years remain a dream. Survival of the crowns is a complex set of interactions between material, fabrication, design, and service variables. In Phase I, our team developed fundamental understanding in damage initiation and accumulation in materials recommended for posterior dental crowns. The influence of microstructure, fatigue and machining parameters on damage have been characterized in monolithic materials. By layering these materials, the conflicting demands for strength and esthetics can be met. Through rational design, the inevitable damage can be managed, yielding a damage tolerant structure which can withstand microcracks within a layer without sacrificing the structural integrity of the system. The overall objective of our revised proposal is to develop a fundamental understanding of damage initiation and accumulation in all-ceramic dental crowns as a function of materials, crown design, and fabrication variables. Our overall approach to meeting this objective is to progress systematically from simple flat-layer structures in normal axial loading toward crown geometries in complex loading, working with clinically-relevant materials at all stages. Ultimately, crowns on extracted teeth mounted in a pseudo bone-PDL system will be subjected to typical cyclic occlusal loading in a wet environment. Our "deliverables" are (1) a design specification guiding development of new materials and (2) fundamental understanding of damage initation, propagation, and accumulation, culminating in a robust model for predicting clinical behavior of combinations of new materials, tooth preparation design, and crown design. With these outcomes, it will be possible for the first time to use basic materials properties to accurately predict application-based performance of new materials. Investigation to accomplish these goals are organized in four projects: (1) Damage Modes and Failure Mechanisms, (2) Complex Loading, Crown Geometry, and Performance, (3) Novel Joining Methods and Interfacial Fracture Mechanics, and (4) Fatigue Performance of Layered Ceramic Crowns on Teeth. The scientific effort will be complemented and supported by two cores: (1) Statistics and Data Analysis Core and (2) Integration and Administration Core.