Objective

To characterize the composition, microstructure and wear properties of a multilayer translucent zirconia relative to the conventional 3Y-TZP.

Methods

Two types of ceramics were evaluated: a multilayer zirconia (MULTI, IPS e.max ZirCAD Multi, Ivoclar Vivadent) and a control 3Y-TZP (IPS e.max ZirCAD LT, Ivoclar Vivadent). Pre-sintered CAD-CAM blocks were cut, ground, sintered and polished to 1 μm finish. The phase fraction and grain size were measured using XRD and FE-SEM. For wear testing (n = 12), square-shaped specimens (16 × 16 × 1 mm) were adhesively bonded to a dentin analog. Sliding wear tests were performed using a spherical zirconia antagonist (r = 3.15 mm), with 30 N load at 1.5 Hz for 500,000 cycles in water. Optical and scanning electron microscopes and 3D laser scanner were used for quantitative wear analyses. Data were analyzed using Student’s t-test (α = 0.05).

Results

For MULTI, the enamel layer had the highest cubic content and the largest grain size, followed by the two transition layers, and the dentin layer. 3Y-TZP showed the smallest grain size and cubic content. A significant amount of wear was observed in both materials up to 50,000 cycles until it reached a plateau. MULTI showed higher volume loss and greater wear depth than 3Y-TZP (p < 0.01). The higher volume loss was associated with extensive lateral fracture, leading to material spalling from the surface of cubic-containing zirconias.

Significance

The wear pattern in multi-layered zirconia was more severe than 3Y-TZP. Additionally, the different layers of the multi-layered zirconia had similar wear behavior.

中文翻译：

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半透明多层氧化锆的磨损行为和微观结构表征。

客观的

表征多层半透明氧化锆相对于传统 3Y-TZP 的成分、微观结构和磨损性能。

方法

评估了两种类型的陶瓷：多层氧化锆（MULTI，IPS e.max ZirCAD Multi，Ivoclar Vivadent）和对照 3Y-TZP（IPS e.max ZirCAD LT，Ivoclar Vivadent）。预烧结的 CAD-CAM 块被切割、研磨、烧结和抛光至 1 μm 光洁度。使用XRD和FE-SEM测量相分数和晶粒尺寸。对于磨损测试 ( n = 12)，将方形样品 (16 × 16 × 1 mm) 粘合到牙本质类似物上。使用球形氧化锆拮抗剂 ( r = 3.15 mm)进行滑动磨损测试，在 1.5 Hz 下以 30 N 负载在水中循环 500,000 次。光学和扫描电子显微镜以及 3D 激光扫描仪用于定量磨损分析。使用Student's t -test ( α = 0.05)分析数据。

结果

对于 MULTI，牙釉质层具有最高的立方含量和最大的晶粒尺寸，其次是两个过渡层和牙本质层。3Y-TZP 显示出最小的晶粒尺寸和立方含量。在长达 50,000 次循环之前，两种材料均观察到显着磨损，直至达到稳定水平。MULTI 显示出比 3Y-TZP 更高的体积损失和更大的磨损深度（p < 0.01）。较高的体积损失与广泛的横向断裂有关，导致材料从含立方氧化锆的表面剥落。

意义

多层氧化锆的磨损模式比 3Y-TZP 更严重。此外，多层氧化锆的不同层具有相似的磨损行为。