Studies on Adhesion of Composite Resins and Glass-Ionomer Cements in Open-Sandwich Technique

Abstract

The aim of this study was to assess the quality of the interface between dental root cement and some restorative materials used in the open sandwich technique. Standardised cavities were prepared on the buccal and oral surfaces of 30 human molars with the gingival margin situated in root cement. The teeth were randomly divided in 3 groups. Different materials combinations were used in buccal and oral cavities. In the control group, the cavities were filled only with composite resins (Filtek Z250-3M ESPE and Zmack Comp-Zermack). In the test groups the cavities were restored using an open sandwich technique as follows: in group 1 Filtek Z250 in combination with Dyract, respectively Ketac Molar Easymix; in group 2 Zmack Comp in combination with Dyract, respectively Ketac Molar. The teeth were stored in 1% methylene blue solution, for 24 hours. The samples were longitudinally sectioned through the centre of restorations and the degree of dye penetration as well as the morphology of the interface between the root cement and the restorative material were evaluated by optical microscopy and SEM. The results showed less microleakage and and adhesive failures in open sandwich restorations with Zmack Comp and Dyract combination.