TY - JOUR
T1 - Effect of ceramic interposition and post-activation times on knoop hardness of different shades of resin cement
AU - Moreno, Marina Barrêto Pereira
AU - Costa, Ana Rosa
AU - Rueggeberg, Frederick Allen
AU - Correr, Américo Bortolazzo
AU - Sinhoreti, Mário Alexandre Coelho
AU - Ambrosano, Gláucia Maria Bovi
AU - Consani, Simonides
AU - Correr-Sobrinho, Lourenço
N1 - Publisher Copyright:
© 2018, Associacao Brasileira de Divulgacao Cientifica. All rights reserved.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - 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.
AB - 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.
KW - Ceramics
KW - Dental materials
KW - Hardness
KW - Polymerization
KW - Resin cements
UR - http://www.scopus.com/inward/record.url?scp=85038423272&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85038423272&partnerID=8YFLogxK
U2 - 10.1590/0103-6440201801635
DO - 10.1590/0103-6440201801635
M3 - Article
C2 - 29267529
AN - SCOPUS:85038423272
SN - 0103-6440
VL - 29
SP - 76
EP - 81
JO - Brazilian dental journal
JF - Brazilian dental journal
IS - 1
ER -