Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Mineralogy, Schlossgarten 5a, 91054 Erlangen, Germany.
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
Dent Mater. 2022 Sep;38(9):1558-1563. doi: 10.1016/j.dental.2022.07.009. Epub 2022 Aug 1.
Here we aim to provide a background on X-Ray Diffraction analysis of quartz-like crystal structures with varying amounts of Al and Li substitution, existing confusions on their nomenclature and its implications for novel lithium silicate glass-ceramics.
We reviewed the literature dealing with modifications of the quartz crystal structure and their stuffed LiAlSiO derivates, LiAlSiO - SiO solid solutions, the terminology of such phases and criteria used to define the structure known as virgilite. Based on this information, we attempted to allocate the quartz-like phases found in CEREC Tessera, Initial LiSi Block and Amber® Mill in the range of LiAlO - SiO solid solutions. For this purpose, their lattice parameters obtained from Rietveld refinement were compared with the lattice parameters of members of the corresponding solid solutions with defined SiO molar fraction found in the literature.
Based on the lattice parameters available for low quartz, high quartz and its stuffed derivatives, including LiAlSiO and the mineral virgilite, a plot of the a- and c-parameters vs. the mol% SiO related to LiAlO was constructed with the literature data and the data found for the three dental lithium silicates. As per the definitions of virgilite as either LiAlSiO, with 0.5 < x < 1 or especially as members of the LiAlSiO - SiO solid-solution series with more than 50 mol% LiAlSiO, the crystal structures in CEREC Tessera, Initial LiSi Block and Amber® Mill failed to fall within the ranges of mol% SiO confined for virgilite.
Based on available literature and definitions, the quartz-like phases found in the three dental lithium silicates should be addressed as stuffed (probably low) quartz solid solutions instead of "virgilite". However determined by mineralogical practices, the term "virgilite" for parts of the LiAlSiO - SiO solid solution is ambiguous and can be considered as arbitrary.
本研究旨在提供关于不同数量 Al 和 Li 取代的石英状晶体结构的 X 射线衍射分析的背景信息，以及对其命名法的现有混淆及其对新型硅酸锂玻璃陶瓷的影响。
我们回顾了有关石英晶体结构及其填充 LiAlSiO 衍生物、LiAlSiO-SiO 固溶体的文献，讨论了这些相的术语以及用于定义称为硅镁锂矿的结构的标准。基于这些信息，我们尝试将 CEREC Tessera、Initial LiSi Block 和 Amber® Mill 中发现的石英状相分配到 LiAlO-SiO 固溶体范围内。为此，我们将从 Rietveld 精修获得的晶格参数与文献中找到的具有定义摩尔分数 SiO 的相应固溶体成员的晶格参数进行了比较。
根据低石英、高石英及其填充衍生物，包括 LiAlSiO 和矿物硅镁锂矿的晶格参数，我们绘制了 a 和 c 参数与摩尔分数 SiO 相对于 LiAlO 的关系图，其中包括文献数据和三种牙科用硅酸锂的数据。根据硅镁锂矿的定义，即 LiAlSiO，0.5 < x < 1，或特别是作为 LiAlSiO-SiO 固溶体系列的成员，具有超过 50 mol% LiAlSiO，CEREC Tessera、Initial LiSi Block 和 Amber® Mill 中的晶体结构未能落入硅镁锂矿的摩尔分数 SiO 范围内。
根据现有文献和定义，在三种牙科用硅酸锂中发现的石英状相应被描述为填充（可能是低）石英固溶体，而不是“硅镁锂矿”。然而，根据矿物学实践，LiAlSiO-SiO 固溶体部分的“硅镁锂矿”一词是模糊的，可以被认为是任意的。
