Self-Healing, Fracture Resistant Restorative Ceramics

自愈、抗断裂修复陶瓷

• 批准号: 6435311
• 负责人: JASON A GRIGGS
• 金额: $ 22.87万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6435311
• 关键词: biomaterial compatibility; biomaterial evaluation; cell mediated lymphocytolysis test; ceramics; clay; composite resins; dental material wear; glass; hardness; oral facial restoration material; porcelain; tensile strength; tooth surface; transmission electron microscopy; water

Dental ceramics are increasingly prolific as restorative materials because of their esthetic appearance and their intrinsic wear resistance, thermal insulation, and biocompatibility. Unfortunately, the currently available dental ceramics are brittle in comparison to dental alloys. This lack of fracture resistance compromises their strength and reliability, resulting in decreased lifetime expectancy. Previous strategies for increasing the lifetimes of dental ceramics have focused on improving the initial strength and tolerance to future damage; however, without a mechanism for repair, damage accumulates, and failure is inevitable. In contrast, natural materials have relatively low resistance to mechanical damage, but their usefulness is maintained over time by healing any damage that is sustained before it accumulates. The overall objective of this project is study self-healing mechanisms by which dental ceramics may exhibit mechanical fatigue resistance and increased longevity. This objective will be accomplished through incorporation of smectite clay particles in hydrothermal glass to form ceramic matrix composites, which will close cracks through the swelling of reinforcing particles. The experimental materials will be designed for use in esthetic, all-ceramic dental restorations. A commercially available low fusing ceramic (Duceram LFC) will be used as the control material for investigation of the following hypotheses: l) moisture- activated swelling of clay particles is a source of increased fracture resistance, 2) a maximum mean free path of 45 mum between reinforcing particles acts as a threshold for increased fracture resistance, 3) a mean reinforcing particle size smaller than 0.39 mum will result in materials with greater translucency than currently available ceramic core materials, 4) smectite clay-reinforced porcelains will exhibit similar or superior biocompatibility compared to unreinforced dental porcelain, and 5) smectite clay-reinforced porcelains will exhibit hardness and abrasive potential lower than those of unmodified dental I porcelain. These efforts may elucidate the mechanisms of fatigue failure and may result in materials that will fill the public demand for long-lasting, esthetic dental restorations.

由于其审美外观以及固有的耐磨损，热绝缘和生物相容性，牙齿陶瓷越来越多地像恢复性材料一样多产。 不幸的是，与牙齿合金相比，当前可用的牙科陶瓷是脆弱的。 缺乏断裂耐药性会损害其强度和可靠性，从而导致终身预期降低。以前提高牙科陶瓷寿命的策略重点是提高对未来损害的最初强度和耐受性；但是，没有维修机制，损坏会积累，并且不可避免地失败。 相比之下，天然材料对机械损伤具有相对较低的抵抗力，但是随着时间的流逝，它们的实用性通过愈合在积累之前遭受的任何损害来维持。该项目的总体目的是研究自我修复机制，牙齿陶瓷可能表现出机械疲劳性和寿命增加。 该目标将通过将绿色粘土颗粒掺入水热玻璃中以形成陶瓷基质复合材料来实现，该陶瓷基质复合材料将通过增强颗粒的肿胀闭合裂缝。实验材料将设计用于审美，全陶瓷牙科修复体。 商业上可用的低融合陶瓷（Duceram LFC）将用作调查以下假设的控制材料：l）水分激活的粘土颗粒肿胀的来源是增加裂缝耐药性的来源，2）最大平均自由路径的最大平均自由路径在3.强化粒子之间的最大平均含量为45 MUM的素质较小的脱粒量增加。与目前可用的陶瓷核心材料相比，透明度比未增强的牙齿瓷器相比将表现出相似或卓越的生物相容性，而与未增强的牙齿瓷器相比，将表现出相似的或卓越的生物相容性，5）5）蒙脱石粘土增强的瓷器将表现出比无效的牙科i Porcelain的硬度表现出的硬度和磨蚀性。 这些努力可以阐明疲劳失败的机制，并可能导致材料，从而满足公众对持久，审美牙齿修复的需求。