Influence of adhesive application methods and rebonding agent application on sealing effectiveness of all-in-one self-etching adhesives.

STATEMENT OF PROBLEM: The choice of adhesive application methods could affect the microleakage of self-etch adhesives. PURPOSE: To evaluate the effect of acid-etching, doubling adhesive application time, doubling adhesive coating, and rebonding agent application on microleakage of self-etch adhesives in Class V cavities. MATERIALS AND METHODS: Seventy human third molars with Class V cavities assigned to five groups according to different adhesive application protocols for the three dentin adhesives (Clearfil S3 Bond, Kuraray Medical, Okayama, Japan; Optibond All-in-One, Kerr Corporation Orange, CA, USA; G-Aenial Bond, GC Corporation, Tokyo, Japan): group 1, manufacturer's recommendations; group 2, prior acid-etching of cavities; group 3, double application time; group 4, two consecutive coats of the adhesives; group 5, rebonding application on restoration margins. After bonding, the cavities were filled with a resin composite (Filtek Supreme XT, 3M ESPE Dental Products, St. Paul, MN, USA). The teeth were thermocycled, and the specimens were examined for microleakage using methylene blue as a marker. RESULTS: For Clearfil S3 Bond and Optibond All-in-One, microleakage in groups 2 and 5 were significantly lower than other groups' enamel margins. In groups 1, 2, 4, and 5, Clearfil S3 Bond exhibited significantly more leakage than the other dentin bonding agents in dentin margins. Microleakage was significantly higher on dentinal margins compared with the enamel margins for Clearfil S3 Bond in all of the groups. Optibond All-in-One showed significantly lower microleakage in dentin margins in all groups except groups 2 and 5. CONCLUSION: Acid-etching usually promoted the reduction of microleakage in enamel margins. On the other hand, rebonding application usually contributed to the reduction of microleakage more than other methods in enamel and dentin margins. CLINICAL RELEVANCE: Acid-etching or rebonding application may contribute to reduction of microleakage of all-in-one self-etching adhesives.