Roulet Jean-François, Sinhoreti Mario Alexandre Coelho, Pontes Stefany, Rocha Mateus Garcia
Center of Dental Biomaterials, Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA.
Center of Dental Biomaterials, Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA; Dental Materials Division, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
J Mech Behav Biomed Mater. 2022 Dec;136:105535. doi: 10.1016/j.jmbbm.2022.105535. Epub 2022 Oct 19.
Dental zirconium oxide restorations are milled from pre-sintered blocks or disks which are produced either with high isostatic pressure (HIP) or, simpler, a slurry technique. The objective was to perform a fatigue test and an in vitro wear simulation of two ceramics, yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramic and a hybrid zirconium oxide-aluminum oxide ceramic, (ATZ) both produced either the classical way using high isostatic pressure (HIP, control) or with a slurry technique.
Ten discs/group were subjected to a cyclic biaxial fatigue test using a staircase approach under water at 37 °C in a dynamic universal testing machine. The 2-body wear test was performed on eight lapped 12 mm thick cylindrical samples subjected to spherical (ø 6 mm) leucite ceramic antagonists in a CS-4 chewing simulator at 49 N force and 0.7 mm lateral movement for 600 k cycles and 4167 thermal cycles (5-55 °C). Volumetric wear was calculated based on laser-scanned surfaces. Selected samples of both tests were viewed in SEM.
All the ceramic specimens produced using the HIP method survived up to 1.2 M cycles with the maximum load of the equipment (1000 N) loading the specimens up to 1527 MPa. The fatigue limit stress at 1.2 M cycles for the Slurry ATZ samples was 946 MPa. For the Slurry Y-TZP samples the fatigue limit stress at 1.2 M cycles was 658 MPa. At 600 k cycles, all zirconium oxide ceramics showed no measurable wear and had a highly polished appearance. The leucite ceramic antagonists wear developed in a linear way. There was no difference between the materials produced with the slurry and the HIP process. ATZ ceramic produced significantly more wear than 3Y- TZP ceramic.
The HIP method provided higher fatigue strength than the Slurry manufacturing method. All HIP ceramics surpassed the limit threshold (1527 MPa) of the testing machine. The tested ceramics did not show any measurable wear but had worn the leucite reinforced glass ceramic antagonists for a considerable amount.
牙科氧化锆修复体由预烧结块或盘铣削而成，这些预烧结块或盘采用高静水压（HIP）或更简单的浆料技术生产。目的是对两种陶瓷进行疲劳试验和体外磨损模拟，这两种陶瓷分别是氧化钇稳定的四方氧化锆多晶体（3Y-TZP）陶瓷和氧化锆-氧化铝混合陶瓷（ATZ），它们均采用传统的高静水压方法（HIP，对照）或浆料技术生产。
每组十个圆盘在动态万能试验机中于37℃水下采用阶梯法进行循环双轴疲劳试验。在CS-4咀嚼模拟器中，对八个研磨后的12毫米厚圆柱形样品进行两体磨损试验，样品与球形（ø6毫米）白榴石陶瓷对磨，施加49 N力和0.7毫米横向移动，进行600 k次循环和4167次热循环（5 - 55℃）。基于激光扫描表面计算体积磨损。对两个试验的选定样品进行扫描电子显微镜观察。
所有采用HIP方法生产的陶瓷试样在设备的最大载荷（1000 N）下承受高达1.2 M次循环，使试样承受高达1527 MPa的压力。浆料法生产的ATZ样品在1.2 M次循环时的疲劳极限应力为946 MPa。对于浆料法生产的Y-TZP样品，在1.2 M次循环时的疲劳极限应力为658 MPa。在600 k次循环时，所有氧化锆陶瓷均未显示出可测量的磨损，且外观高度抛光。白榴石陶瓷对磨体的磨损呈线性发展。浆料法和HIP法生产的材料之间没有差异。ATZ陶瓷产生的磨损明显多于3Y-TZP陶瓷。
HIP方法提供的疲劳强度高于浆料制造方法。所有HIP陶瓷均超过了试验机的极限阈值（1527 MPa）。测试的陶瓷未显示出任何可测量的磨损，但使白榴石增强玻璃陶瓷对磨体有相当程度的磨损。
