THIN FILM SURFACE COATINGS FOR TOUGHENED DENTAL CERAMICS

描述（改编自研究者摘要）：非金属 (e.g.,汞替代）修复材料是一个高度优先的研究 这是由于与金属废物和处理相关的环境问题。 陶瓷是一个有趣的候选人，以取代金属基修复 材料.牙科应用中的陶瓷提供优异的化学性能， 耐用性、耐磨性、生物相容性、环境友好性， 美学然而，全瓷修复体的广泛使用受到以下因素的阻碍： 与边缘抗断裂性和临床寿命相关的问题。 先前的研究（Kelly等人，1989; Thompson等人，1994年）发现， 全瓷修复体的临床断裂起始于沿着内表面 (e.g.,粘合表面）几乎完全。因此， 如果这些材料要得到广泛应用， 验收这项研究的总体目标是生产出坚韧， 薄膜等离子体沉积抗疲劳陶瓷涂层 陶瓷表面涂层提出了四个具体目标。目标1建议 研究来验证溅射沉积薄膜的应用 涂层将提高传统商业 牙科陶瓷材料至少50%。目标2建议进行研究， 溅射沉积具有细晶粒（小于1 μ m）薄膜的假设 微结构将产生具有显著 比具有柱状结构的薄膜具有更大的断裂韧性 晶粒结构目标3提出了一些研究来检验这一假设， 溅射沉积的薄膜陶瓷涂层的厚度不会不利地影响 与牙科粘结剂的界面韧性或光学特性 （透射率、折射率和L*a*B* 颜色参数） 道歉目的4提出检验假设，即多层和/或 组成渐变的薄膜表面涂层将产生基底/薄 具有比所获得的断裂韧性显著更大的断裂韧性的膜构造 具有单一成分的薄膜。候选沉积材料包括Al 2 O 3， ZrO 2、MgAl 2 O 4、AlN、Si 3 N4、SiC和类金刚石C。将创建涂层 使用RF磁控溅射沉积。多层和成分梯度 将使用多靶和反应溅射沉积来产生涂层。 断裂韧性将由受控缺陷断裂强度确定 方法和断口分析评价的缺陷。疲劳 行为将通过开发寿命预测曲线来表征。扫描电镜， TEM和AFM将用于表征界面和微观结构， 沉积薄膜。

DESCRIPTION (adapted from Investigator's abstract): 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 intriguing candidate for replacing metal-based restorative materials. Ceramics in dental applications provide excellent chemical durability, wear resistance, biocompatibility, environmental friendliness, and esthetics. However, widespread all-ceramic restoration use has been hindered by concerns related to marginal fracture resistance and clinical longevity. Previous studies (Kelly et al., 1989; Thompson et al., 1994) 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 research is to produce tough, fatigue-resistance ceramic restorations by applying thin film plasma-deposited ceramic surface coatings. Four specific aims are proposed. Aim 1 proposes studies to test the hypothesis that application of sputter deposited thin film coatings will enhance fracture and fatigue resistance of traditional commercial dental ceramic materials by at least 50%. Aim 2 proposes studies to test the hypothesis that sputter deposited thin films with fine-grained (less than 1 um microstructures will yield substrate/thin film constructs with significantly greater fracture toughness than achieved with thin films possessing columnar grain structures. Aim 3 proposes studies to test the hypothesis that presence of sputter deposited thin film ceramic coatings will not adversely affect the interfacial toughness with dental luting cements or the optical characteristics (transmittance, index of refraction, and L*a*b* color parameters) of modified restorations. Aim 4 proposes to test the hypotheses that multilayer and/or compositionally graded thin film surface coatings will yield a substrate/thin film construct with significantly greater fracture toughness than is achieved with unicompositional thin films. Candidate deposition materials include Al2O3, ZrO2, MgAl2O4, AlN, Si3N4, SiC, and diamond-like C. Coatings will be created using RF magnetron sputter deposition. Multilayer and compositionally graded coatings will be created using multiple target and reactive sputter deposition. Fracture toughness will be determined by controlled-flaw fracture strength methods and fractographic evaluation of fracture-initiating flaws. Fatigue behavior will be characterized by developing lifetime prediction profiles. SEM, TEM, and AFM will be used to characterize interfaces and microstructures of deposited thin films.