High Toughness Textured Ceramics for Biomedical Use

描述：牙科对具有与天然牙齿相匹配的高强度和光学特性的陶瓷有很高的需求，在重建手术中对具有提高韧性的生物活性陶瓷有很高的需求。我们之前的工作导致了一种新型玻璃陶瓷的发展，使用传统的实验室技术是可压的。该材料具有织构的微观结构和提高的韧性。本提案的总体目标是开发一种结合高强度和优异美学的牙科玻璃陶瓷。另一个目标是生产具有提高韧性的生物活性陶瓷。织构材料的韧性与织构和显微组织的程度直接相关。我们生产高强度牙科陶瓷的方法是优化织构，促进亚微观次生云母相的成核，减少压制品中的缺陷密度和尺寸。纹理细化将通过两种技术来实现：在温度梯度下进行热处理，然后热压或在热压后对玻璃进行热处理。通过添加AIPO4作为成核剂来调整微观结构。通过加入La203来提高玻璃基体的折射率，从而减少晶体与玻璃相的折射率不匹配，从而改善半透明性。减少缺陷密度和尺寸将通过消除压制后存在的表面层和对压制陶瓷进行热处理以促进裂纹愈合来实现。具有增强韧性的生物活性陶瓷将通过热压生产。采用热分析、XRD、SEM等方法对其结晶行为和热性能进行研究。采用SEM和XRD对其织构程度进行研究。表层将用x射线反射仪和能谱仪进行分析。机械和光学性能将在有纹理、无纹理和市售陶瓷作为对照进行测量。实验设计采用自适应采样方案来优化光学和机械性能，并整合不同的目标。潜在的应用包括牙修复、牙种植体上层结构和骨替代种植体。

DESCRIPTION: There is a high demand in dentistry for ceramics that combine high strength and optical properties matching those of natural teeth, and in reconstructive surgery for bioactive ceramics with improved toughness. Our previous work has led to the development of a novel glass-ceramic that is pressable using conventional laboratory techniques. This material exhibits a textured microstructure and improved toughness. The overall objective of this proposal is to develop a dental glass-ceramic that combines high strength and excellent esthetics. An additional goal is to produce bioactive ceramics with improved toughness. Toughness in textured materials is directly related to the degree of texture and microstructure. Our approach to producing high strength dental ceramics is to optimize the texture, promote the nucleation of a submicroscopic secondary mica phase and reduce flaw density and size in the pressed product. Texture refinement will be achieved via two techniques: heat treatment in a temperature gradient followed by heatpressing or heat treatment of the glass after heat-pressing. Microstructure will be tailored by adding AIPO4 as a nucleating agent. Translucency will be improved by adding La203 to increase the refractive index of the glassy matrix, thereby reducing the mismatch between the indices of crystalline and glassy phases. Reduction in flaw density and size will be achieved by eliminating the surface layer present after pressing and by heat treatment of the pressed ceramic to promote crack healing. Textured bioactive ceramics with improved toughness will be produced via heat pressing. The crystallization behavior and thermal properties will be studied by thermal analysis, XRD and SEM. The degree of texture will be investigated by SEM and XRD. The surface layer will be analyzed by X-ray reflectometry and EDS. The mechanical and optical properties will be measured on textured, non-textured and commercially available ceramics as controls. The experimental design uses an adaptive sampling scheme to optimize the optical and mechanical properties and integrate the different aims. Potential applications include dental restorations, dental implant superstructures, and bone replacement implants.