Microleakage of three different combinations of adhesive and composite resins

Aim The aim of the present study was to evaluate the influence of 3 adhesive systems on microleakage of direct composite restorations with proximal margins under the cement-enamel junction (CEJ) and in the enamel. Materials and methods  In 30 extracted molars standardized MOD (mesio-occlusal-distal) cavities were prepared with a proximal margin located 1 mm under the cement-enamel junction and another one in the enamel, and subsequently randomly divided in 3 groups of 10 using 3 different adhesives and the same composite: Flowable (G-aenial Universal Injectable, GC) + universal adhesive (G2-Bond universal, GC) with selective-etch technique (Group 1); Flowable (G-aenial Universal Injectable, GC) + self-etch adhesive (Clearfil SE Bond 2, Kuraray) with 2-step technique (Group 2); Flowable (G-aenial Universal Injectable, GC) + total-etch adhesive (Optibond FL, Kerr) with 3-step technique (Group 3). Samples were tested for microleakage using silver nitrate and infiltration was classified in 5 levels. The differences in microleakage were statistically evaluated with significance set at P<0.05. Results In the margin located in the enamel, group 1 showed an average of 0 microleakage, group 2 an average of 0.2 and group 3 an average of 0.1. In the margin located in the dentin, group 1 showed an average score of 1.1, group 2 of 2.15 ang group 3 of 1.25. No statistically significant difference was found in the enamel. Conclusion The combination of adhesive G2-Bond universal and Optibond FL showed the highest sealing ability both in margins located in the enamel and margins located in the dentin. The adhesive interface in the enamel produced a very good seal, while the adhesive interface in the dentin showed varying degrees of microleakage in all groups.