OBJECTIVE To evaluate the cyclic contact fatigue resistance and failure mode of ceramics for monolithic and multilayer restorations. METHODS Ceramic structures (10 mm × 1.8 mm) were fabricated as follows (n = 28): (1) CAD-on- trilayer structure composed of Y-TZP (yttria stabilized tetragonal zirconia polycrystal- IPS e.max ZirCAD) infrastructure, fusion glass-ceramic (IPS e.max CAD Crystall/Connect) and lithium disilicate-based glass-ceramic (IPS e.max CAD); (2) ZFC- bilayer structure composed of Y-TZP infrastructure veneered by a fluorapatite glass-ceramic (IPS e.max Ceram); (3) LDC- monolithic lithium-disilicate glass-ceramic (IPS e.max CAD); and (4) YZW- monolithic Y-TZP (Zenostar Zr Translucent). All ceramics structures were bonded to a dentin analog substrate (G10). Specimens were submitted to cyclic contact fatigue test in a pneumatic cycling machine with 80 N load and 2 Hz frequency in distilled water at 37 °C. Test was interrupted after 104, 105, 5 × 105 and 106 cycles and the presence or absence of failure was recorded. Fatigue data were analyzed using Kaplan-Meier (log rank) and Holm-Sidak tests (α = 0.05). The relationship between the type of crack leading to failure and the experimental group was analyzed using chi-square test (α = 0.05). RESULTS There was no statistical difference between CAD-on and YZW groups (p = 0.516), which presented the highest survival rates after cyclic loading, followed by ZFC and LDC groups (p < 0.01). There was a significant relationship between type of crack and experimental group (p < 0.001). LDC specimens showed the greatest frequency of radial cracks, while cone cracks were more prevalent for ZFC and CAD-on specimens. SIGNIFICANCE Monolithic Y-TZP (YZW) showed similar fatigue resistance to CAD-on multilayer specimens, but different failure mode. Monolithic lithium disilicate glass-ceramic (LDC) and Y-TZP conventionally veneered by glass-ceramic (ZFC) showed lower survival time under fatigue.

中文翻译：

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用于整体和多层牙科修复体的陶瓷的抗循环接触疲劳性能。

目的评估整体和多层修复用陶瓷的循环接触疲劳强度和破坏模式。方法陶瓷结构（10 mm×1.8 mm）的制造方法如下（n = 28）：（1）由Y-TZP（氧化钇稳定的四方氧化锆多晶-IPS e.max ZirCAD）基础设施，融合的三层CAD结构玻璃陶瓷（IPS e.max CAD Crystall / Connect）和基于二硅酸锂的玻璃陶瓷（IPS e.max CAD）; （2）ZFC-双层结构，由Y-TZP基础结构组成，表面饰有氟磷灰石玻璃陶瓷（IPS e.max Ceram）；（3）LDC-单片二硅酸锂玻璃陶瓷（IPS e.max CAD）；（4）YZW-整体式Y-TZP（Zenostar Zr Translucent）。将所有陶瓷结构粘结到牙本质类似物基底（G10）上。在37°C的蒸馏水中，样品在80 N负载和2 Hz频率的气动循环机中经受了循环接触疲劳测试。在104、105、5×105和106个循环后中断测试，并记录是否存在故障。使用Kaplan-Meier（对数秩）和Holm-Sidak检验（α= 0.05）分析疲劳数据。使用卡方检验（α= 0.05）分析导致破裂的裂纹类型与实验组之间的关系。结果CAD-on组和YZW组之间无统计学差异（p = 0.516），其在循环负荷后呈现最高生存率，其次是ZFC和LDC组（p <0.01）。裂纹类型与实验组之间存在显着关系（p <0.001）。LDC样品显示出最大的径向裂纹频率，而ZFC和CAD-on标本的圆锥裂纹更为普遍。重要性单片Y-TZP（YZW）的疲劳强度与多层CAD样品相似，但破坏模式不同。单片二硅酸锂玻璃陶瓷（LDC）和常规由玻璃陶瓷（ZFC）贴面的Y-TZP在疲劳下的存活时间较短。