Wertz Markus, Fuchs Florian, Hoelzig Hieronymus, Wertz Julia Maria, Kloess Gert, Hahnel Sebastian, Rosentritt Martin, Koenig Andreas
Department of Prosthodontics and Material Sciences, Leipzig University, 04103 Leipzig, Germany.
Institute of Mineralogy, Crystallography and Materials Science, Leipzig University, 04103 Leipzig, Germany.
Materials (Basel). 2021 Apr 22;14(9):2133. doi: 10.3390/ma14092133.
The effect of dental technical tools on the phase composition and roughness of 3/4/5 yttria-stabilized tetragonal zirconia polycrystalline (3y-/4y-/5y-TZP) for application in prosthetic dentistry was investigated. Additionally, the X-ray diffraction methods of Garvie-Nicholson and Rietveld were compared in a dental restoration context. Seven plates from two manufacturers, each fabricated from commercially available zirconia (3/4/5 mol%) for application as dental restorative material, were stressed by different dental technical tools used for grinding and polishing, as well as by chewing simulation and thermocycling. All specimens were examined via laser microscopy (surface roughness) and X-ray diffraction (DIN EN ISO 13356 and the Rietveld method). As a result, the monoclinic phase fraction was halved by grinding for the 3y-TZP and transformed entirely into one of the tetragonal phases by polishing/chewing for all specimens. The tetragonal phase t is preferred for an yttria content of 3 mol% and phase t″ for 5 mol%. Mechanical stress, such as polishing or grinding, does not trigger low-temperature degradation (LTD), but it fosters a phase transformation from monoclinic to tetragonal under certain conditions. This may increase the translucency and deteriorate the mechanical properties to some extent.
研究了牙科技术工具对用于口腔修复的3/4/5钇稳定四方多晶氧化锆（3y-/4y-/5y-TZP）相组成和粗糙度的影响。此外，还在牙齿修复背景下比较了Garvie-Nicholson和Rietveld的X射线衍射方法。来自两个制造商的七块板材，每块均由市售氧化锆（3/4/5摩尔%）制成，用作牙齿修复材料，通过用于研磨和抛光的不同牙科技术工具以及咀嚼模拟和热循环进行应力处理。所有试样均通过激光显微镜（表面粗糙度）和X射线衍射（DIN EN ISO 13356和Rietveld方法）进行检查。结果，对于3y-TZP，通过研磨单斜相分数减半，对于所有试样，通过抛光/咀嚼完全转变为四方相之一。对于3摩尔%的氧化钇含量，四方相t是优选的，对于5摩尔%，四方相t″是优选的。机械应力，如抛光或研磨，不会引发低温降解（LTD），但在某些条件下会促进从单斜相到四方相的相变。这可能会增加透明度并在一定程度上降低机械性能。
