This study investigated the mechanical properties, bond ability, and crystallographic forms of different sites in a highly translucent, multi-layered zirconia disk. Flexural properties, bond ability to resin cement, and phase composition were investigated at three sites of a highly translucent, multi-layered zirconia disk: incisal, middle, and cervical. Flexural strength (FS) and flexural modulus (FM) were measured with static three-point flexural test. Shear bond strength (SB) to resin cement was measured after 24 h storage (37°C). Phase composition under mechanical stress was analyzed using X-ray diffraction. Without air abrasion, FS at the incisal site yielded the lowest value and was significantly lower than the middle and cervical sites. Air abrasion lowered the FS of each site. FM at the incisal site without air abrasion showed the significantly lowest value, and air abrasion increased its FM value. At the middle and cervical sites, their FM values were higher than the incisal site but were not significantly affected by air abrasion. SB value did not show significant differences among the sites. After sintering, cubic zirconia was detected at each site. Rhombohedral phase transformation occurred after mirror polishing. In highly translucent, multi-layered zirconia which was mainly composed of cubic zirconia, rhombohedral phase transformation occurred under mechanical stress and resulted in weakened mechanical properties.

中文翻译：

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高度半透明多层氧化锆的弯曲性能、结合能力和晶相

本研究调查了高度半透明的多层氧化锆圆盘中不同位点的机械性能、结合能力和结晶形式。在高度半透明的多层氧化锆圆盘的三个部位研究了弯曲特性、与树脂水泥的粘合能力和相组成：切端、中间和颈部。弯曲强度（FS）和弯曲模量（FM）通过静态三点弯曲试验测量。在储存 24 小时 (37°C) 后测量与树脂水泥的剪切粘合强度 (SB)。使用 X 射线衍射分析机械应力下的相组成。在没有空气磨损的情况下，切端处的 FS 产生最低值，明显低于中间和颈部位点。空气磨损降低了每个站点的 FS。没有空气磨损的切端的FM值显着最低，空气磨损增加了其FM值。在中部和颈部，它们的 FM 值高于切端，但不受空气磨损的显着影响。SB 值在站点之间没有显示出显着差异。烧结后，在每个位置检测到立方氧化锆。镜面抛光后发生菱面体相变。在以立方氧化锆为主成分的高透明多层氧化锆中，在机械应力作用下发生菱面体相变，导致力学性能减弱。SB 值在站点之间没有显示出显着差异。烧结后，在每个位置检测到立方氧化锆。镜面抛光后发生菱面体相变。在以立方氧化锆为主成分的高透明多层氧化锆中，在机械应力作用下发生菱面体相变，导致力学性能减弱。SB 值在站点之间没有显示出显着差异。烧结后，在每个位置检测到立方氧化锆。镜面抛光后发生菱面体相变。在以立方氧化锆为主成分的高透明多层氧化锆中，在机械应力作用下发生菱面体相变，导致力学性能减弱。