Influence Of Self-Etching-Priming Bonding Systems On Sealing Ability Of Class II Restorations: Leakage And Sem Evaluation Fabianelli A*, Vichi A, Grandini S, Ferrari M, Davidson C. L. (School Of Dental Medicine, Siena University, Italy) Aim of this study was to evaluate sealing ability of different types of restorative-adhesive combinations and to correlate etch patterns with leakage scores. 42 posteriors teeth were selected. The teeth were divided at random in three groups of fourteen samples each. A standardized adhesive Class II preparation with the cervical margin placed 1 mm below the CEJ and an occlusal reduction of 2 mm was performed. No bevels were utilized in the preparation.   Three combinations of bonding system/restorative material were tested. Group 1: Excite (EX, Vivadent) in combination with Tetric Ceram (TC, Vivadent) as control; Group 2: Prompt-Pop self etching-priming adhesive system (PP1, Espe) applied for 15 sec. in combination with TC; Group 3: Etch and Prime 3.0 in combination with Definite restorative material (EP, Degussa). The bonding systems and all restorative materials were used following strictly manufacturers' instructions. The resin composite was applied following an incremental technique. 10 samples of each group were processed for leakage test. The samples were sectioned with a diamond saw (Isomet) in three different points in mesial-distal direction. Two different operators evaluated the sections in double blind for scoring leakage at cervical and occlusal margins. The worst score for the sections of each tooth area was selected for scoring and further statistical analysis. The results of the staining measurements were statistically evaluated using the Kruskal-Wallis non-parametric analysis of variance with Bonferroni alpha protection. The level of statistical significance was defined P= 0.05. The remaining 4 samples each group were kept in a 37% HCL solution to completely dissolve the dental structures and to observe the resin replica of the cavities by SEM. EX showed less dye penetration at occlusal margins than the other 2 groups, while no statistical significant differences were found cervically. The SEM observations showed rougher and more uniform enamel etch pattern when phosphoric acid (EX) was applied than that obtained with self-etching-priming bonding systems.   Resin tags and adhesive lateral branches were noted in all groups at the dentin site. It can be concluded that phosphoric acid bonding systems can seal the enamel margins better than self-etching-priming bonding materials.