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课题。陶瓷是替代金属基修复材料的理想选择。陶瓷具有优异的化学耐久性；耐磨、生物相容性好、环保、美观。然而，全陶瓷修复体的广泛应用一直受到与边缘抗骨折性和临床寿命相关的担忧的阻碍。先前的研究发现，全陶瓷修复体的临床断裂几乎完全是沿着内表面（例如粘合表面）开始的。因此，如果这些材料得到广泛接受，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，从而开发更坚固，更耐疲劳的全陶瓷牙科修复体。迄今为止，在最初资助的NIH拨款范围内进行的研究主要集中在沉积膜的微观结构控制和评估它们对改性陶瓷基板机械行为的影响。ZrO2已被确定为最合适的薄膜涂层材料。此外，还发现ZrO2薄膜对与改性牙科陶瓷表面的粘合或半透明陶瓷的美观性没有有害影响。这项持续研究的具体目的是：(1)验证溅射沉积ZrO2薄膜内部残余应力状态和分布可以通过控制沉积参数重现性地控制，从而产生具有可预测抗断裂性的结构体的假设；(2)验证了高、低模量层交替沉积的多层薄膜可以制备出比单层薄膜具有更大韧性的基板/薄膜层压板结构，以及(3)验证了溅射沉积的ZrO2薄膜的加入可以显著提高传统商用牙科陶瓷材料制备的试件的抗疲劳性能。该技术需要进一步研究，以建立更详细的了解沉积参数，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，如果要开发临床有效的工艺。

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.