This in vitro study evaluates the influence of pressed lithium disilicate thickness, shade and translucency on the transmitted irradiance and the Knoop microhardness (KHN) of a light-cured resin cement at two depths. One hundred and thirty-five ceramic discs of IPS e.max Press (Ivoclar Vivadent) were fabricated and divided into twenty-seven groups (n = 5) according to the association between translucency: HT (hight translucency), LT (low translucency), and MO (medium opacity); shade: BL2, A1 and A3.5; and thickness: 0.5 mm, 1.5 mm, and 2.0 mm. One side of each ceramic disc was finished, polished and glazed. The irradiance (mW/cm²) of a multiwave LED light curing unit (Valo, Ultradent) was evaluated with a potentiometer (Ophir 10ª-V2-SH, Ophir Optronics) without (control group) or with interposition of ceramic samples. The microhardness of Variolink Esthetic LC resin cement (Ivoclar Vivadent) was evaluated after 24 h at two depths (100 μm and 700 μm). Data were submitted to ANOVA followed by Tukey’s test (α = 0.05). Irradiance and KHN were significantly influenced by ceramic thickness (p < 0.0001), shade (p < 0.001), translucency (p < 0.0001) and depth (p < 0.0001). Conclusions: the interposition of increasing ceramic thicknesses significantly reduced the irradiance and microhardness of resin cement. Increased depth in the resin cement showed significantly reduced microhardness for all studied groups. Increased ceramic opacity reduced the KHN of the resin cement at both depths for all ceramic thicknesses and shades.

这项体外研究评估了压制二硅酸锂的厚度、颜色和半透明度对光固化树脂水泥在两个深度的透射辐照度和努氏显微硬度 (KHN) 的影响。制作了 135 个 IPS e.max Press (Ivoclar Vivadent) 的陶瓷圆盘，分为 27 组（n = 5) 根据半透明之间的关联：HT（高半透明）、LT（低半透明）和 MO（中等不透明度）；色度：BL2、A1 和 A3.5；和厚度：0.5 毫米、1.5 毫米和 2.0 毫米。每个陶瓷圆盘的一侧都经过抛光、抛光和上釉。多波 LED 光固化装置 (Valo, Ultradent) 的辐照度 (mW/cm²) 使用电位计 (Ophir 10ª-V2-SH, Ophir Optronics) 在没有（对照组）或插入陶瓷样品的情况下进行评估。Variolink Esthetic LC 树脂粘固剂 (Ivoclar Vivadent) 的显微硬度在 24 小时后在两个深度（100 μm 和 700 μm）进行评估。将数据提交给 ANOVA，然后进行 Tukey 检验 ( α  = 0.05)。辐照度和 KHN 受陶瓷厚度 ( p  < 0.0001)、阴影 ( p < 0.001)、半透明度 ( p  < 0.0001) 和深度 ( p  < 0.0001)。结论：增加陶瓷厚度的介入显着降低了树脂水泥的辐照度和显微硬度。树脂粘固剂中深度的增加表明所有研究组的显微硬度显着降低。对于所有陶瓷厚度和色调，增加的陶瓷不透明度降低了树脂水泥在两个深度的 KHN。