Staining and microleakage evaluation of re-sealing in class V restorations

Objective: The purpose of this in vitro study was to evaluate the microleakage, superficial and marginal staining of composite restorations after re-sealing. Methods: Twenty cavities had been prepared for class V restorations on buccal and lingual surfaces of ten third molars (4 mm height, 4mm width and 2mm depth) with a stainless steel carbide bur. The cavities were restored using the adhesive system Clearfil SE Bond (Kuraray) and the Renew composite (BISCO) in three increments. After finishing and polishing the restorations were randomly assigned in two groups (n=10). Group A: No re-sealing. Group B: re-sealed with a surface sealant Biscover (BISCO). The groups were thermocycled (5000 cycles), impermeabilized, immersed in basic fuscine 0.5% (24h), washed, dried and photographed to estimate the degree of marginal and superficial staining. The pictures were projected and the superficial and marginal stainings were classified as: absent (1), located (2) or generalized (3), and analyzed by the Kruskall Wallis test. The specimens were included in epoxy resin and sectioned, obtaining 3 to 4 slices of 1mm thickness each. The slices were photographed, inserted and measured with the software Image Tool. The data were analyzed by ANOVA. Results: In comparison of the marginal staining there was no significant difference between the groups (P=1). Re-sealing had the highest staining (median 30.5) than the group without re-sealing (median 14.5) on the superficial staining (P<0.001). In comparison of the microleakage below the CEJ, Group B had the least microleakage (median 2.7 ±0.23). This was statistically less than Group A (median 3.27 ± 0.12) (P<0.001). Above the CEJ, there was also a statistically significant difference between groups B (median 1.49 ± 0.21) and A (median 2.65 ± 0.16) (P<0.001). Conclusion: The re-sealing reduced the marginal microleakage. However, this procedure increased the superficial and marginal staining of the composite restorations.