The effect of different distance of curing light and ceramic materials on microhardness of the resin

Abstract

SUMMARY Aim:The aim of this study was to evaluate the effect of different curing distances and ceramic materials on the microhardness of dual-cured resin cement. Materials and Methods:The dual-cured resin cement (NX3, Kerr) was polymerized between between lithium disilicate based pressed ceramic (IPS e.max Press (EP)), or three different CAD/CAM materials (Lava Ultimate (LU), e.max CAD (EC), Vita Suprinity (VS)) and a dentine surface with a LED light source from 0, 3 or 6 mm distances for 10 seconds (n=10). The Vickers microhardness (VH) values were recorded immediately after polymerization and after storage at dark in distilled water (24 h/37°C). Three indentations were made both on the top and the bottom surface of each specimen. ANOVA was used to analyse the data. Bonferroni test was used to perform multiple comparisons (p<0.05). Results: The resin cements under the LU specimens have significantly higher VH values compared to the other materials (p<0.05). The bottom surfaces have significantly lower hardness values for all ceramic materials (p<0.05). The VH value of 0 mm curing tip-ceramic distance was significantly higher than the groups of 3 and 6 mm distances (p<0.05). Microhardness values were significantly higher after 24 hours than immediate measurement (p<0.05). Conclusion: Ceramic material and the curing tip-ceramic distance are important factors to be considered for obtaining adequate polymerization.