Bonding systems used for sealing: evaluation of microleakage

To evaluate multi-use bonding systems as the sole material for sealing pits and fissures, this study compared the performance of three adhesives (OptiBond, All-Bond 2 and Scotchbond MP Plus) with respect to microleakage. Each material was applied to 12 teeth with dry-etched surfaces, and to 12 teeth with contaminated-etched surfaces (1 microliter of human plasma). Each group of 12 sealed teeth was divided into three subgroups, and each of these was subjected either to thermal cycling (4,000 cycles at 5-55 degrees C), to thermal and load cycling (4,000 plus 300,000 cycles) or to no cycling. The teeth were placed in a 50% AgNO3 solution, rinsed, immersed in a developing solution and exposed to a fluorescent light. Subsequently, each of the 72 crowns was sectioned at three different positions, generating 432 cross-sections. The severity of dye penetration on each cross-section was evaluated by two methods. An ANOVA was used to assess the main effects of the three factors (product, surface condition and cycling), as well as for their interactions on the severity of microleakage. The results obtained under both evaluation methods demonstrated that OptiBond had the best performance under either dry or contaminated surfaces, while All-Bond 2 and Scotchbond MP Plus performed similarly, with greater microleakage intensity on contaminated etched enamel compared to OptiBond.