Yttria-partially stabilized zirconia: using the transformed layer as a permeable membrane for the infiltration of materials

3Y-TZP(3Y-TZP)是一种独特的牙科用陶瓷，其晶体结构(从四方相到单斜相-t-m)具有相变-增韧机制。然而，体温、循环载荷和湿度等条件会导致四方相向单斜相的转变速度加快，从而改变了3Y-TZP在原始加工状态下的特性。这个3Y-TZP转换区从表面向下延伸到材料的整体。此外，3Y-TZP被认为是生物惰性的，由于缺乏骨整合，限制了其作为牙种植体的应用。3Y-TZP在化学上也是惰性的，因此缺乏与活性单体的化学作用，无法粘合到牙齿结构和其他陶瓷材料上。为了改善3Y-TZP与其他基材之间的结合，迄今已完成的大多数研究都试图通过表面氧化铝喷砂来增加表面粗糙度。然而，这一过程损害了3Y-TZP的力学性能，粘结强度的结果并不确定。3Y-TZP时效时，由于马氏体片的移动，导致表面m斑点和晶粒拔出相结合，并在其下方形成微裂纹层。我们的初步数据表明，3Y-TZP的t-m转变层是多孔的，可以用于薄膜的渗透。因此，我的研究计划的长期目标是开发一种陶瓷材料，为牙科应用提供可靠的生物力学性能。在短期内，我的目标是利用RT-ALD技术开发3Y-TZP t-m转换层和硅/钛氧化物之间的混合界面。因此，本研究计划的三个主要目标是：1：定义3Y-TZP t-m转化层的理想厚度作为孔隙率和机械性能的函数；2：开发一种在3Y-TZP转化层和二氧化硅基纳米薄膜之间产生混杂界面的方法，以使3Y-TZP与其他材料之间能够更好地结合；3：开发一种在3Y-TZP转化层和二氧化钛基纳米薄膜之间产生杂化界面的方法，以实现更好的骨整合。3Y-TZP转换层的特性是一个大的科学界感兴趣的，在不断寻找更稳定和更容易接受的氧化锆基衬底的过程中。它还将通过在装备精良的环境中提出多学科方法，对高素质人员的培训产生影响。

Three-mol% Yttria-tetragonal zirconia polycrystal (3Y-TZP) is a unique ceramic for dental application, due to the transformability of the crystallographic structures (from tetragonal to monoclinic – t-m), which is responsible for the transformation-toughening mechanism. However, conditions such as body temperature, cyclic loading and humidity cause the tetragonal-to-monoclinic (t-m) phase transformation to happen at a faster pace, changing the 3Y-TZP's characteristics in the original processed state. This 3Y-TZP transformed zone runs from the surface down to the bulk of the material. Furthermore, 3Y-TZP is considered biologically inert, which restricts its application as a dental implant due to the lack of osseointegration. 3Y-TZP is also chemically inert, resulting in lack of chemical interaction with active monomers for bonding to the tooth structure and to other ceramic materials. To improve the bonding between 3Y-TZP and other substrates, most of the studies done so far attempted to increase surface roughness through surface alumina blasting. However, this procedure compromises the mechanical performance of 3Y-TZP and bond strength results are inconclusive. 3Y-TZP aging results in the combination of surface m spots and grain pull-out, and a microcracked layer underneath as a consequence of the dislodgement of the martensitic plates. Our preliminary data indicate that the 3Y-TZP t-m transformed layer is porous and may be used for the infiltration of thin films. Therefore, the long-term objective of my research program is to develop a ceramic-based material that presents reliable biomechanical performance for dental application. In the short-term, my goal is to develop a hybrid interface between 3Y-TZP t-m transformed layer and silicon/titanium oxides using RT-ALD. Therefore, the 3 main objectives of this research program are: 1: to define the ideal thickness of the 3Y-TZP t-m transformed layer as a function of porosity and mechanical properties; 2: to develop a method to produce a hybrid interface between 3Y-TZP transformed layer and silica-based nanofilm to enable better bonding between 3Y-TZP and other materials; 3: To develop a method to produce a hybrid interface between 3Y-TZP transformed layer and titania-based nanofilm to enable better osseointegration. The characterization of the 3Y-TZP transformed layer is of interest to a large scientific community, in the continuous search for more stable and more receptive zirconia-based substrates. It will also impact the training of high-qualified personnel, by proposing a multidisciplinary approach in a well-equipped environment.