ABSTRACT
Two important disadvantages of amalgam restorations are lack of adhesion to tooth structure and marginal leakage. In recent studies, the use of dentin adhesive on cavity walls before the insertion of amalgam proved to be the best method to reduce microleakage and increase chemical adhesion. Fourty premolar and molar teeth were collected and divided into two groups. The class V cavities were made at the buccal surfaces of the teeth [Depth 1. 5 mm, Length 3 mm and Width 2 mm]. All the angles of cavo-surfaces were Buttjoint. The teeth were then washed, cleaned, dried and randomly divided into 2 groups, the first group was coated with 2 layers of varnish. The second group was coated with adhesive resin system and then restored with amalgam. The teeth were kept in distilled water for 24 hours. The prepared surfaces were then polished and thermocycling was performed. All prepared surfaces were coated with nail varnish up to 0.5 mm around the restorative material. Further more each group was randomly divided into 2 subgroups, one group was kept in distilled water for 24 hours and the other group for 5 months. All groups were afterwards kept in 0.5% basic fuchsin solution for 24 hours. The teeth were then mounted in Acrylic resin, were cut into two halves from the centre of preparation with a diamond saw and checked by a stereomicroscope for determining the microleakage rate. Comparison between two groups showed degree of dye penetration into margins of restorations with Rely X ARC was lower than that of varnish. However no significant differences were observed among the groups except for occlusal margins after 24 hours and 5 months