Thin Film Surface Coating for Toughened Dental Ceramics

描述：由于与金属废物和处置相关的环境问题，非金属(例如，汞合金替代品)修复材料的开发是一个高度优先的研究重点。陶瓷是替代金属基修复体材料的理想材料。陶瓷具有优异的化学耐久性、耐磨性、生物兼容性、环境友好性和美观性。然而，全瓷修复体的广泛应用受到了与边缘抗折能力和临床寿命相关的担忧的阻碍。以前的研究发现，临床上全瓷修复体的断裂几乎完全是沿着内表面(如粘结表面)开始的。因此，如果这些材料要得到广泛的接受，克服断裂问题是至关重要的。这项持续研究的总体目标是通过实施射频等离子溅射沉积的薄膜陶瓷表面涂层，最大限度地减少或消除表面缺陷的灾难性影响，从而开发出更坚韧、更耐疲劳的全瓷修复体。到目前为止，在美国国立卫生研究院的初始资助范围内进行的研究主要集中在沉积薄膜的微观结构控制以及评估它们对改性陶瓷衬底的机械行为的影响。氧化锆被认为是最合适的薄膜涂层材料。此外，研究还发现，氧化锆薄膜对修饰后的牙科陶瓷表面的粘结没有不良影响，也不会影响半透明陶瓷的美观。这项持续研究的具体目的是：(1)测试假设，即通过控制沉积参数，可以重复地控制溅射沉积的ZrO2薄膜中的残余应力状态和分布，以产生具有可预测的断裂抗力的结构，(2)测试假设，即沉积具有高和低模数交替的多层薄膜，可以生产出比单层薄膜具有更大断裂韧性的衬底/薄膜层压结构，(3)测试假设，即加入溅射沉积的ZrO2薄膜将显著提高由传统商业牙科陶瓷材料制成的试件的疲劳抗力。如果要开发一种临床有效的工艺，这项技术需要进一步研究，以建立更详细的沉积参数、薄膜微结构和改性陶瓷的短期和长期力学行为之间的关系。

DESCRIPTION: Development of non-metallic (e.g., amalgam-substitute) restorative materials is a high research priority due to environmental concerns associated with metals waste and disposal. Ceramics are an ideal candidate for replacing metal-based restorative materials. Ceramics provide excellent chemical durability; wear resistance, biocompatibility, environmental friendliness, and esthetics. Nevertheless, widespread all-ceramic restoration use has been hindered by concerns related to marginal fracture resistance and clinical longevity. Previous studies found that clinical fracture of all-ceramic restorations initiated along internal surfaces (e.g., bonded surfaces) almost exclusively. It is therefore critical to overcome fracture problems if these materials are to gain widespread acceptance. The overall goal of this continued research is to develop tougher, more fatigue-resistant all-ceramic dental restorations by minimizing or eliminating catastrophic effects of surface flaws through the implementation of RF-plasma sputter deposited thin-film ceramic surface coatings. Research conducted to date within the initial funded NIH grant has focused on microstructural control of deposited films and assessing their affect on the mechanical behavior of modified ceramic substrates. ZrO2 has been identified as the most appropriate thin film coating material. In addition, it has been found that ZrO2 thin-films produce no deleterious effect on bonding to a modified dental ceramic surface, or on the esthetic appearance of a translucent ceramic. The Specific Aims of this continued research are to: (1) test the hypothesis that the residual stress state and distribution within sputter deposited ZrO2 thin-films can be reproducibly controlled through manipulation of deposition parameters to produce constructs with predictable fracture resistance, (2) test the hypothesis that deposition of multi-layered thin-films with alternating high and low modulus layers can be used to produce substrate/thin-film laminate constructs with significantly greater facture toughness than is achieved with single-layer thin films, and (3) test the hypothesis that incorporation of sputter deposited ZrO2 thin-films will significantly enhance the fatigue resistance of specimens fabricated from traditional commercially available Dental ceramic materials. This technology needs further study to establish a more detailed understanding of the relationships between deposition parameters, thin-film microstructures, and short and long-term mechanical behavior of modified ceramics if a clinically efficacious process is to be developed.