Use of one-bottle adhesive as an intermediate bonding layer to reduce sealant microleakage on saliva-contaminated enamel

Purpose: To evaluate the influence of three different adhesives, each used as an intermediary layer, on microleakage of sealants applied under conditi on of salivary contamination. Materials and Methods: Six different experime ntal conditions were compared, 3 with adhesives and 3 without. After prophy laxis and acid etching of enamel, salivary contamination was placed for 10 s. In Group SC the sealant was applied after saliva without bonding agent a nd then light-cured. In Group SCA, after saliva, the surface was air dried, and then the sealant was applied and cured. In Groups ScB, SE and PB, a bo nding agent (Scotchbond Dual Cure/3M, Single Bond/3M and Prime & Bond 2.1/D entsply, respectively) was applied after the saliva and prior to the sealan t application and curing. After storage in distilled water at 37 degreesC f or 24 hrs, the teeth were submitted to 500 thermal cycles (5 degreesC and 5 5 degreesC), and silver nitrate was used as a leakage tracer. Leakage data were collected on cross sections as percentage of total enamel-sealant inte rface length. Representative samples were evaluated under SEM. Results: Sea lants placed on contaminated enamel with no bonding agent showed extensive microleakage (94.27% in SC; 42.65% in SCA). The SEM revealed gaps as wide a s 20 mum in areas where silver nitrate leakage could be visualized. In cont rast, all bonding agent groups showed leakage less than 6.9%. Placement of sealant with a dentin-bonding agent on contaminated enamel significantly re duced microleakage (P< 0.0001). The use of a bonding agent as an intermedia ry layer between enamel and sealant significantly reduced saliva's effect o n sealant microleakage.