In-vitro Marginal Sealing Ability of an Experimental Dentin Bonding Agent

Objective: The aim of this in vitro study was to compare marginal sealing ability of Class V resin composite restorations using an experimental dentin bonding agent (Prime & Bond XP). Methods: Thirty caries free human premolars were selected. In each tooth, one standardized 3mm cylindrical shaped Class V cavity of 1.5mm depth was prepared, with occlusal margins ending in enamel and gingival margins in dentin. The teeth were randomly assigned into 2 groups (n=15), according to the technique of application of the bonding agent (single or double application). The adhesive systems were applied according to the manufacturer’s instructions. All cavities were restored with Dyract AP. After polishing, the specimens were thermocycled (500x, 5-55oC, 30s dwell time) in 0.5% basic fuchsin solution. The specimens were sectioned longitudinally and dye penetration was quantified according to a 0-4 scale on the enamel and dentine surfaces independently. Data was analysed using SPSS software package. Results: No significant differences were seen on the enamel between a single and double layer application. A significant difference was however found on the dentin, where 14% of the sample with a single application showing no microleakage and 53% of the sample with a double application showing no microleakage (p<0.005). Conclusion: This study shows that a double layer of bonding agent on dentin significantly reduces microleakage.