Department of Condensed Matter Physics, University of Seville, Spain.
Int J Oral Maxillofac Implants. 2012 Jul-Aug;27(4):785-91.
Yttria-stabilized zirconia (ZrO₂-Y₂O₃) ceramics have received increasing attention in recent years because of their stress-induced tetragonal-to-monoclinic (martensitic) transformation. This unique process acts as a toughening mechanism, imparting strength and toughness to the ceramic alloy. This property, along with well-documented biocompatibility, is now being exploited in an increasing number of medical applications, including implant dentistry. To prevent clinical problems and predict their behavior and physical limitations, a characterization of the ceramic elements used in dental restorations is essential. The aim of the present study is to characterize the crystal structure, elemental composition, and micr ostructure of asreceived ZiReal Post (Biomet 3i) zirconium oxide abutments, as well as specimens coated with a first layer of a low-fusing fluoroapatite ceramic.
Zirconium oxide abutments, both as-received and porcelain-coated, were studied using the following techniques: x-ray diffraction, x-ray fluorescence, energy dispersive x-ray spectroscopy, optical microscopy, and scanning and transmission electron microscopy.
X-ray analyses detected only the presence of Zr, O, Y, and hafnium (Hf), in an amount of 3% to 4% molecular weight Y₂O₃-ZrO₂. X-ray diffraction measurements showed that the ceramic abutment crystallizes mainly in the tetragonal phase, with some residual monoclinic phase. The microstructure is characterized by a rather homogenous grain distribution, formed by equiaxed and fine grains with a mean size of 0.30 Μm.
Compositional and diffraction results are consistent with polycrystalline yttria-stabilized tetragonal zirconia. The material is susceptible to undergoing the stress-induced transformation toughening mechanism because of the very fine grain size. Except for machining ring marks, the surfaces exhibit an excellent finishing quality. No structural modifications were observed in the fluoroapatite ceramic-coated abutments because of the relatively low temperatures used for ceramization compared with the phase transformation temperatures used for zirconia.
近年来，由于氧化钇稳定氧化锆（ZrO₂-Y₂O₃）陶瓷的压应力诱导四方相到单斜相（马氏体）转变，其受到越来越多的关注。这种独特的转变过程充当了增韧机制，为陶瓷合金赋予强度和韧性。由于其具有良好的生物相容性，这种特性现在越来越多地应用于医疗应用中，包括种植牙。为了防止临床问题，并预测其行为和物理局限性，对牙科修复体中使用的陶瓷元素进行特征描述是至关重要的。本研究的目的是对收到的 ZiReal Post（Biomet 3i）氧化锆基台的晶体结构、元素组成和微观结构进行特征描述，以及对涂覆有第一层低熔氟磷灰石陶瓷的样品进行特征描述。
使用以下技术对收到的和涂瓷的氧化锆基台进行研究：X 射线衍射、X 射线荧光、能量色散 X 射线光谱、光学显微镜、扫描电子显微镜和透射电子显微镜。
X 射线分析仅检测到存在 Zr、O、Y 和铪（Hf），其重量百分比为 3%到 4%的 Y₂O₃-ZrO₂。X 射线衍射测量表明，陶瓷基台主要以四方相结晶，存在一些残余的单斜相。微观结构的特征是具有相当均匀的晶粒分布，由等轴和细小晶粒组成，平均晶粒尺寸为 0.30 Μm。
组成和衍射结果与多晶氧化钇稳定四方氧化锆一致。由于晶粒非常细小，该材料容易发生应力诱导相变增韧机制。除了加工环纹外，表面还具有出色的精整质量。由于氟磷灰石陶瓷涂层基台的烧成温度相对较低，与氧化锆相变温度相比，没有观察到结构改性。
