Influence of crystalline phase transformation induced by airborne-particle abrasion and low-temperature degradation on mechanical properties of dental zirconia ceramics stabilized with over 5 mol% yttria
Influence of crystalline phase transformation induced by airborne-particle abrasion and low-temperature degradation on mechanical properties of dental zirconia ceramics stabilized with over 5 mol% yttria
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影响%20of%20结晶%20相%20转化%20诱导%20by%20空气颗粒%20磨损%20和%20低温%20降解%20on%20机械%20性能%20of%20牙科%20氧化锆%20陶瓷%20稳定%20with%20over%205%
DOI：
10.1016/j.jmbbm.2021.104890
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Ortengren U
中科院分区：
文献类型：
--
作者：
Nakamura K;Tarkeshi A;Niklasson A;Shishido S;Svanborg P;Barkarmo S;Ortengren U
已经开发了由5摩尔%氧化钇稳定的氧化锆（5 YZ）制造的整体式牙科假体以改善传统的3摩尔%氧化钇稳定的氧化锆的透光性。在这项研究中，我们的目的是评估空气颗粒磨损（阿帕）和低温降解（LTD）与结晶相转变的5 YZ的机械性能的影响。总共制备了两个品牌的5 YZ（Lava Esthetic和Katana UTML）的120个盘形试样。将标本分为四组（每组n = 15）：（i）对照组，（ii）阿帕组，（iii）LTD组和（iv）阿帕+ LTD组。用50 μm氧化铝颗粒进行阿帕，并通过在134 °C下高压灭菌50 h诱导LTD。根据ISO 6872：2015使用活塞-三球试验评估试样的双轴弯曲强度，并使用显微硬度计测定维氏硬度。通过X射线衍射图的Rietveld精修分析晶相。阿帕显着增加了熔岩美学标本的弯曲强度，而LTD几乎不影响这两种材料的强度。阿帕和阿帕+ LTD显著提高了两种材料的维氏硬度。根据Rietveld分析，假立方相在两种材料中占主导地位，即，在Lava Esthetic和Katana UTML样本中分别为66质量%和81质量%。阿帕诱导的菱形相在两种材料中约为37质量%，而LTD诱导的单斜相在熔岩美学标本中为2.8质量%，在卡塔纳UTML标本中为0.9质量%。阿帕+ LTD对菱面体相的量影响较弱，但略微增加了单斜相的量。这些结果表明，阿帕可以提高5 YZ的机械性能，特别是硬度，通过生成的菱面体相。相比之下，LTD对5 YZ的力学和显微组织性能的影响是有限的。
Monolithic dental prostheses fabricated from 5 mol% yttria-stabilized zirconia (5YZ) have been developed to improve the translucency of conventional 3 mol% yttria-stabilized zirconia. In this study, we aimed to evaluate the influence of airborne-particle abrasion (APA) and low-temperature degradation (LTD) on the mechanical properties of 5YZ in association with the crystalline phase transformation. In total, 120 disc-shaped specimens of two brands of 5YZ (Lava Esthetic and Katana UTML) were prepared. The specimens were divided into four groups (n = 15 for each group): (i) control, (ii) APA, (iii) LTD, and (iv) APA + LTD groups. APA was performed with 50 μm alumina particles, and LTD was induced by autoclaving at 134 °C for 50 h. The biaxial flexural strength of the specimens was assessed using a piston-on-three-ball test according to ISO 6872:2015, and Vickers hardness was determined using a microhardness tester. The crystalline phase was analyzed by the Rietveld refinement of X-ray diffraction patterns. APA significantly increased the flexural strength of the Lava Esthetic specimens, whereas LTD hardly affected the strength of both materials. APA and APA + LTD significantly increased the Vickers hardness of both materials. According to Rietveld analysis, the pseudocubic phase was predominant in both materials, i.e., 66 mass% and 81 mass% in the Lava Esthetic and Katana UTML specimens, respectively. APA induced the rhombohedral phase at approximately 37 mass% in both materials, while LTD induced the monoclinic phase at 2.8 mass% in the Lava Esthetic specimens and 0.9 mass% in the Katana UTML specimens. APA + LTD weakly affected the amount of the rhombohedral phase but slightly increased the amount of the monoclinic phase. These findings suggest that APA may improve the mechanical properties of 5YZ, particularly hardness, via the generation of the rhombohedral phase. In contrast, the influence of LTD on the mechanical and microstructural properties of 5YZ was limited.