Sousa Edisa O, Alves Larissa M M, Campos Tiago M B, Bergamo Edmara T P, Benalcazar-Jalkh Ernesto B, Marun Manoela M, Galli Mateus Z, Carvalho Laura F, Dos Santos Claudinei, Tebcherani Sergio M, Thim Gilmar Patrocínio, Zhang Yu, Yamaguchi Satoshi, Witek Lukasz, Coelho Paulo G, Bonfante Estevam A
Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil.
Department of Prosthodontics and Periodontology, Bauru School of Dentistry, University of São Paulo, Bauru, SP 17012-901, Brazil; Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Dent Mater. 2025 Apr;41(4):391-401. doi: 10.1016/j.dental.2024.12.012. Epub 2025 Jan 13.
To characterize two experimental zirconia bilayer materials compared to their monolithic controls, before and after hydrothermal aging.
Commercial zirconia powders were utilized to fabricate two bilayer materials: 3Y-TZP+ 5Y-PSZ (3Y+5Y/BI) and 4Y-PSZ+ 5Y-PSZ (4Y+5Y/BI), alongside control groups 3Y-TZP (3Y/C), 4Y-PSZ (4Y/C), and 5Y-PSZ (5Y/C). Compacted specimens were sintered (1550 °C- 2 h, 3 °C/min), and half of them underwent hydrothermal aging (134 °C-20h, 2.2 bar). Characterizations were performed through scanning-electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, reflectance tests and biaxial flexural strength test (ISO:6872). Weibull statistics were applied to determine the characteristic strength and Weibull modulus. Grain size and optical properties were analyzed using two-way ANOVA followed by the Tukey test.
Degradation regions and monoclinic phase were observed at aged 3Y-TZP and 4Y-PSZ surfaces. Significant differences were observed in the evaluation of optical properties between the bilayer and control groups. The bilayer materials presented intermediate characteristic strength values compared to their controls and aging significantly increased the strength of some groups.
Experimental bilayer materials presented lower mechanical properties than monolithic controls, 3Y/C and 4Y/C. Hydrothermal aging increased the characteristic strength of bilayered and monolithic controls, except for 5Y-PSZ. Both experimental bilayer systems, as well as monolithic controls, met the ISO 6872:2015 requirements for single-unit crowns (100 MPa), 3-unit fixed dental prostheses (FDPs) up to premolars (300 MPa), and 3-unit FDPs involving molars (500 MPa). However, for FDPs with four or more units, only monolithic 3Y-TZP and 4Y-PSZ, and bilayered 3Y+5Y met the required minimum flexural strength (≥800 MPa).
对比两种实验性氧化锆双层材料与其整体对照材料在水热老化前后的特性。
使用商用氧化锆粉末制备两种双层材料：3Y-TZP+5Y-PSZ（3Y+5Y/BI）和4Y-PSZ+5Y-PSZ（4Y+5Y/BI），同时设置对照组3Y-TZP（3Y/C）、4Y-PSZ（4Y/C）和5Y-PSZ（5Y/C）。将压实的试样进行烧结（1550℃-2小时，3℃/分钟），其中一半进行水热老化（134℃-20小时，2.2巴）。通过扫描电子显微镜（SEM）、X射线衍射（XRD）、拉曼光谱、反射率测试和双轴弯曲强度测试（ISO:6872）进行表征。应用威布尔统计来确定特征强度和威布尔模量。使用双向方差分析和Tukey检验分析晶粒尺寸和光学性能。
在老化的3Y-TZP和4Y-PSZ表面观察到降解区域和单斜相。双层材料和对照组在光学性能评估方面存在显著差异。与对照组相比，双层材料呈现出中间特征强度值，并且老化显著提高了一些组的强度。
实验性双层材料的机械性能低于整体对照材料3Y/C和4Y/C。水热老化提高了双层材料和整体对照材料的特征强度，但5Y-PSZ除外。两种实验性双层系统以及整体对照材料均符合ISO 6872:2015对单冠（100MPa）、前磨牙以下的3单位固定义齿（FDP）（300MPa）以及涉及磨牙的3单位FDP（500MPa）的要求。然而，对于四个或更多单位的FDP，只有整体的3Y-TZP和4Y-PSZ以及双层的3Y+5Y满足所需的最小弯曲强度（≥800MPa）。
