Understanding the microstructural bonding mechanisms between Y-TZP and veneering ceramic

牙科贴面氧化锆基核修复迄今已被广泛使用。氧化锆核与瓷贴面材料分层，以实现适当的美学效果。然而，氧化锆基瓷贴面可能会产生临床问题，如瓷贴面层的碎裂或断裂。先前的研究已经报道了单板失效的显著发生率，例如分层、碎裂和开裂。这种断裂行为可归因于差的单板/芯界面结合强度、芯材料与单板之间的弹性模量不匹配、芯与单板之间的热膨胀系数不匹配、弱的瓷强度和热过程（其可引入由冷却速率和/或高温烧结引起的残余应力）。为了改善瓷核界面的相容性，避免早期破坏，需要对瓷核/氧化锆界面有更深入的了解。* 拟议的研究将调查氧化锆/陶瓷界面处粘附的详细机制，以开发可行的解决方案来改善这两种材料之间的结合，使用两种成型技术（分层技术和压制技术）。还将评价热应力。本研究的主要目的是表征陶瓷和氧化锆之间的相互作用，然后根据结果开发材料或新设计。因此，全瓷修复体的瓷贴面与氧化锆核之间可以获得更好的粘结稳定性。瓷贴面与氧化锆的结合力是氧化锆基瓷贴面成功的基础。在确定新的方案和/或设计以制造氧化锆基涂层之后，将进行机械测试。*不同的测试将仔细进行，以描述氧化锆/瓷结合的微观结构机制。测试包括SEM、EDS、电子背散射衍射（EBSD）。此外，显微组织，织构，缺陷，晶粒形态和变形也将通过EBSD进行评估。此外，聚焦离子束显微镜（FIB）将用于制备TEM和飞行时间二次离子质谱（TOF-SIMS）的薄样品。俄歇微探针将有助于以高空间分辨率确定表面上的二维和三维元素分布。还将通过XPS检查氧化锆与瓷的结合形成。*本研究的结果是为牙科实验室提供一种新的制作牙科贴面氧化锆基核修复体的方法，以提高这种牙科修复体的成功率。新方案将基于从本研究结果中获得的氧化锆/瓷界面处的详细粘结机制。5年多来，我将培养3名研究生。

Dental veneered zirconia-based core restorations have been used widely to date. The zirconia core is layered with a porcelain veneer material to achieve suitable esthetics. However, zirconia-based restorations can create clinical issues such as chipping or fracture of the porcelain veneered layer. Previous studies have reported a significant incidence of veneer failures such as delaminations, chipping and cracking. This fracture behavior could be attributed to the poor veneer/core interface bond strength, elastic modulus mismatch between the core material and the veneer, coefficient of thermal expansion mismatch between the core and the veneer, weak porcelain strength and thermal procedure which could introduce residual stress induced by cooling rate and/or sintering at high temperatures. To improve the compatibility at the interface between veneer and core, and to avoid premature failure, the interface zirconia/porcelain should be better understood. ***The proposed research will investigate the detailed mechanism for the adhesion at the interface zirconia/porcelain to develop a feasible solution to improve the bonding between these two materials, using both molding techniques (the layering technique and the press technique). The thermal stresses will be also evaluated. The main objectives of this study are to characterize the interaction between porcelain and zirconia then, materials or new designs will be developed based on the results. Therefore, better bonding stability between porcelain veneer and zirconia core of an all-ceramic restoration can be achieved. The adhesion of porcelain veneer to zirconia is fundamental for the success of the zirconia-based restorations. After determining the new protocol and/or design to fabricate zirconia-based restorations, mechanical tests will be performed.***Different tests will be carefully conducted to describe the microstructural mechanisms of zirconia/porcelain bond. The tests are SEM, EDS, Electron Backscatter Diffraction (EBSD). Furthermore, microstructures, texture, defects, grain morphology and deformation will also be evaluated by EBSD. In addition, the Focused Ion Beam microscopy (FIB) will be used to prepare thin specimens for the TEM and for Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). Auger Microprobe will contribute to the determination of 2D and 3D elemental distributions on surfaces with high spatial resolution. The bond formation of the zirconia to porcelain will also be examined by XPS.***The outcome of the research is to provide the dental laboratories with a new protocol to fabricate dental veneered zirconia-based core restorations in order to improve the success rate of this type of dental restoration. The new protocol will be based on the detailed bond mechanisms at the zirconia/porcelain interface obtained from the results of this study. Over 5 years, I will train 3 graduate students.