Background and Aim: Although the use of adhesive systems can be effective in decreasing microleakge, it is still a major problem in composite resin restorations. The aim of the present study was to evaluate the marginal sealing ability of resin composite restorations using four dentin bonding systems in both primary and permanent teeth.

Materials and Methods: In this experimental study, one hundred and sixty extracted human teeth (80 primary and 80 permanent) were selected. All of the samples received a class V cavity preparation on the buccal surfaces (The coronal half in enamel and the gingival half in cementum or dentin). Each group was then divided into four subgroups each containing 20 teeth. Four different dentin bonding systems (Scotchbond Multipurpose, Single Bond, Clearfil SE Bond and Prompt L-Pop) were used in each subgroup. Then the cavities were filled with composite resin (Z100 for SBMP and Clearfil AP-X for Clearfil SE Bond). Samples were thermocycled, immersed in 0.5% basic fuschin, cut faciolingually and evaluated for dye penetration using a binocular stereomicroscope. Kruskal-Wallis and Dunn tests were used for comparison of microleakage between groups with p<0.05 as the limit of significance.

Results: The results showed that: There was significant difference in microleakage among four adhesive systems in both incisal and gingival margins of permanent teeth and in incisal margin of primary teeth (P=0.000, P=0.002, P=0.000 respectively). There was no significant difference in microleakage of restorations with each of four systems between permanent and primary teeth in both incisal and gingival margins except for PLP, which showed a significant different microleakage in the cervical margins (P=0.009). PLP showed better cervical seal in primary teeth compared to permanent teeth. Clearfil SE Bond showed acceptable results at incisal and cervical margins in primary teeth in comparison to other bonding systems.

Conclusion: Based on the results of this study, CSEB, SB and SBMP systems showed acceptable clinical results in primary and permanent teeth. Only PLP showed weak results in reducing microleakage. CSEB can be used successfully in primary teeth because of simplicity and reducing leakage in primary dentin and enamel.