Analysis of quality of polymerization of resin cement used in cementation on ceramic crowns with different substrates through microhardness tests

Abstract

The resin cements have been widely used to lute restorations due to mechanical, physical and aesthetic properties. However, the degree of conversion achieved influences their mechanical properties, biocompatibility and degradation by water and oral acids. Microhardness tests can be applied to estimate the degree of conversion of cements. The aim of this study will be to evaluate the microhardness of the resin cement Variolink II (Ivoclar-Vivadent, Liechtenstein), used in cementation on pure ceramic crowns submitted to curing as recommended by manufacturer. Thirty human molars crowns will be prepared to receive pure ceramics crowns and then the specimens will be divided into three groups for the cementation. In group A, the crowns will be cemented on prepared teeth on dentin. In groups B and C, the crowns will be sectioned in cement enamel junction and the cores will be made with metal and resin filler, respectively. Each one of the groups will be subdivided into two subgroups to evaluate after 7 days and 3 months of storage in deionized water. The specimens will be sectioned in the center of crowns, buccal-lingually and the inner surface will be polished to microhardness tests. The average microhardness values will be obtained for the cervical, middle and occlusal of the buccal and lingual faces. The data will be compared by ANOVA testing (among 3 criteria) and Tukey's post hoc test. (AU)