Effect of lithium disilicate ceramic thickness, shade and translucency on transmitted irradiance and knoop microhardness of a light cured luting resin cement

• Published in: Journal of materials science. Materials in medicine Vol. 32; no. 8; p. 90
• Main Authors: Borges, Lincoln Pires Silva, Borges, Gilberto Antônio, Correr, Américo Bortolazzo, Platt, Jeffrey A., Kina, Sidney, Correr-Sobrinho, Lourenço, Costa, Ana Rosa
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2021; Springer Nature B.V; Springer
• Subjects: Acrylic Resins; Biomaterials; Biomaterials Synthesis and Characterization; Biomedical Engineering and Bioengineering; Biomedical materials; Bone Cements; Cement; Ceramics; Ceramics - chemistry; Chemistry and Materials Science; Composite Resins; Composites; Curing Lights, Dental; Dental cement; Dental Porcelain - chemistry; Glass; Hardness; Irradiance; Light; Light emitting diodes; Light-Curing of Dental Adhesives; Lithium; Materials Science; Materials Testing; Microhardness; Natural Materials; Opacity; Polymer Sciences; Polymerization; Polyurethanes; Potentiometers; Regenerative Medicine/Tissue Engineering; Reproducibility of Results; Resin Cements; Resins; Shade; Shades; Surfaces and Interfaces; Temperature; Thickness; Thin Films; Variance analysis
• ISSN: 0957-4530; 1573-4838
• 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.