Effect of ceramic interposition and post-activation times on knoop hardness of different shades of resin cement

Marina Barrêto Pereira Moreno, Ana Rosa Costa, Frederick Allen Rueggeberg, Américo Bortolazzo Correr, Mário Alexandre Coelho Sinhoreti, Gláucia Maria Bovi Ambrosano, Simonides Consani, Lourenço Correr-Sobrinho

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The aim of this study was to evaluate Knoop hardness of different shades of a resin cement light-cured directly or through ceramic discs, measured 15 min or 24 h after light exposure, and at different depths. Specimens of a commercial resin cement (Variolink Veneer) in seven shades, were fabricated in an elastomeric mold, covered with a mylar strip, a 0.7 mm thick ceramic disc (IPS e.max Press) was placed and the cement was light-activated for 20 s using a blue LED (Radii-Cal). The cured resin cement specimens were transversely wet-flattened to their middle portion and microhardness (Knoop) values were recorded at 15 min after light exposure and after deionized water storage at 37 °C for 24 h. Five indentations were made in the cross-sectional area at 100 and 700 µm depths from the top surface. Ten specimens were made for each test conditions. Data were submitted to ANOVA split-plot design (shade, post-cure time, mode of activation and depth), followed by Tukey post hoc test (α=0.05). Significant differences for shade (p<0.0001), mode of activation (p<0.001), post-cure time (p<0.0001) and depth (p<0.0001) were detected. No significant interactions (p>0.05) were found, except for shade x post-cure time (p<0.0045) and mode of activation x post-cure time (p<0.0003). Resin cement shade has a significant effect on Knoop hardness. Indirect activation through a ceramic material reduced significantly Knoop hardness. Hardness Knoop significantly increased after 24 h in all cements shades compared to values obtained after 15 min. Resin cement depth significantly reduced Knoop hardness.

Original languageEnglish (US)
Pages (from-to)76-81
Number of pages6
JournalBrazilian dental journal
Issue number1
StatePublished - Jan 1 2018


  • Ceramics
  • Dental materials
  • Hardness
  • Polymerization
  • Resin cements

ASJC Scopus subject areas

  • Dentistry(all)


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