Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas - UNICAMP, Piracicaba, SP, Brazil.
Department of Dental Materials and Restorative Dentistry, University of Uberaba, Uberaba, MG, Brazil.
J Mater Sci Mater Med. 2021 Jul 31;32(8):90. doi: 10.1007/s10856-021-06562-2.
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.
本体外研究评估了加压锂硅石厚度、色调和半透明度对两种深度下光固化树脂水门汀传输光强和维氏硬度（KHN）的影响。制作了 135 个 IPS e.max Press（义获嘉伟瓦登特）陶瓷圆盘，并根据半透明度（HT：高半透明度、LT：低半透明度、MO：中等不透明度）、色调（BL2、A1 和 A3.5）和厚度（0.5mm、1.5mm 和 2.0mm）将其分为 27 组（每组 5 个）。每个陶瓷圆盘的一侧进行加工、抛光和上釉。使用电位计（Ophir 10ª-V2-SH，Ophir Optronics）评估多波长 LED 光固化单元（Valo，Ultradent）的光强（mW/cm²），无需（对照组）或在陶瓷样品之间插入时进行评估。在 24 小时后，在两个深度（100μm 和 700μm）评估 Variolink Esthetic LC 树脂水门汀的维氏硬度。数据采用方差分析（ANOVA）和 Tukey 检验（α=0.05）进行分析。光强和 KHN 显著受到陶瓷厚度（p<0.0001）、色调（p<0.001）、半透明度（p<0.0001）和深度（p<0.0001）的影响。结论：增加陶瓷厚度会显著降低树脂水门汀的光强和维氏硬度。树脂水门汀的深度增加会导致所有研究组的维氏硬度显著降低。所有陶瓷厚度和色调的陶瓷不透明度增加会降低树脂水门汀在两个深度的 KHN。
