FRACTURE CHARACTERISTICS OF DENTAL COMPOSITES

牙科复合材料的断裂特性

• 批准号: 2015035
• 负责人: James Drummond
• 金额: $ 10.37万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-30 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2015035
• 关键词: atomic absorption spectrometry; biomaterial evaluation; composite resins; dental material wear; dental materials; dental stress analysis; gas chromatography; mass spectrometry; mechanical stress; water

The hypothesis of this proposal is that mode I fracture testing of dental composite is insufficient to represent what occurs under clinical conditions and requires the mixed mode approach to fracture analysis. The second portion of the hypothesis is that leached/degraded components from the aging of the composite in water require additional analysis as to qualification and quantification, their rate of removal, and their influence on the fracture properties. The significance of the continuation of the initial project is to extend the understanding and knowledge gained in the first phase on the aging, strength(sf), toughness (KIc), elasticity( E), and crack growth studies. The proposed Continuation consists of three interrelated objectives: 1. Fatigue, fracture, and failure under combIned complex loading condItions and various environments. Failure of dental composites. when used as restorations can occur from cracks or flaws which may be arbitrarily oriented with respect to the applied load. Therefore, complex loading conditions (simultaneous fracture modes I and II) will be investigated since the simulate better a fracture process in a dental restoration. This mixed mode approach will provide a envelope of the fracture threshold from which the ability to predict more realistically lifetime survival under complex loads is possible. 2. Investigations of the effects of the water-matrix-filler interactions on the overall mechanical and environmental stability of dental composites. it is well recognized in the mechanics of composite research that bulk or macro properties (Sf, E, and KIc) are dependent on the micro structure. Thus, the effects of water on the matrix material and reinforcing particles will be thoroughly examined through chemical analyses (atomic absorption and gas chromatography mass spectrometry) as well as materials' morphology characterization (microprobe analysis). Emphasis will be placed on the effect of water in the first one to three months of aging on strength and fracture properties since our investigations showed negligible changes in the fracture properties from six to twelve months. 3. Studies on the effects of specimen size and notch tip geometry on strength, toughness, and fatigue characteristics. Dental composites are inherently brittle materials. Thus essential fracture properties are dependent upon the local notch tip geometry and specimen size. Our preliminary studies have shown that different notch tip geometry yield fracture toughness values which differ up to 60%. In the proposed continuation, the effects of notch tip radius and depth will be tested in various environments.

该提议的假设是牙齿的骨折测试模式 复合材料不足以表示临床下发生的情况 条件并需要混合模式的裂缝分析方法。这 假设的第二部分是从 水中复合材料的老化需要对 资格和量化，其删除率以及他们的 对断裂特性的影响。意义的意义 最初项目的继续是扩展理解和 在第一阶段获得的知识，强度（SF），韧性 （KIC），弹性（E）和裂纹生长研究。提议 延续由三个相互关联的目标组成： 1。疲劳，断裂和混合复合载荷下的故障 条件和各种环境。牙科复合材料的失败。什么时候 用作修复的裂缝或缺陷可能会发生 就施加的负载任意定向。因此，复杂 加载条件（同时骨折模式I和II）将是 进行了调查，因为在牙齿中模拟了更好的断裂过程 恢复。这种混合模式方法将提供一个信封 断裂阈值，从中更现实预测的能力 在复杂载荷下的终身生存是可能的。 2。对水垫填充剂相互作用的影响的研究 关于牙齿的整体机械和环境稳定性 复合材料。它在复合研究的机制中得到了广泛认可 该体积或宏观特性（SF，E和KIC）取决于微型 结构。因此，水对基质材料和 将通过化学彻底检查增强颗粒 分析（原子吸收和气相色谱质谱法） 以及材料的形态表征（微探针分析）。 重点将放在第一到三的水的影响上 自我们 调查显示，骨折特性的变化可忽略不计 六到十二个月。 3。关于样品尺寸和缺口尖端几何影响的影响的研究 力量，韧性和疲劳特征。牙科复合材料是 固有的易碎材料。因此，必需的断裂特性是 取决于局部缺口尖端几何形状和样品尺寸。我们的 初步研究表明，不同的缺口尖端几何产率 裂缝韧性值高达60％。在提议中 继续，将测试Notch Tip半径和深度的效果 在各种环境中。