Purpose: To evaluate the effect of long-term water storage on the microleakage of a fissure sealant applied with or without different bonding agents.

Materials and methods: Extracted human third molars were randomly assigned into 8 groups (n = 24/each). The occlusal surfaces were sealed with a fluoride fissure sealant material (Helioseal F) after one of the following pretreatments: (1) phosphoric acid etching only; (2) phosphoric acid etching + Single Bond; (3) phosphoric acid etching + Prime & Bond NT; (4) Clearfil SE Bond; (5) FL Bond; (6) One Up Bond F; (7) Prompt L-Pop; (8) Mac Bond II. All specimens were thermocycled (1000X), after which half of them (n=96) were stored in distilled water for 48 h (group A), and the remaining half (n=96) for 48 months (group B). The specimens were immersed in 0.5% basic fuchsin solution, sectioned, and digitally photographed. Microleakage was evaluated quantitatively using an open-source image analysis toolkit (ImageJ), and the data were analyzed statistically.

Results: Four-year water storage significantly increased the amount of leakage in all test groups (p < 0.001). In both the absence and presence of water aging, the etch-and-rinse adhesives yielded the lowest microleakage scores (p < 0.001). In the 48-h group, the following ranking was achieved in terms microleakage values: phosphoric acid + Prime & Bond NT = phosphoric acid + Single Bond < Prompt L-Pop = phosphoric acid etching only < FL Bond < Clearfil SE Bond < Mac Bond II = One Up Bond F. In the 48-month group, the ranking changed as follows: phosphoric acid + Prime & Bond NT = phosphoric acid + Single Bond < Prompt L-Pop = FL Bond < Clearfil SE Bond = Mac Bond II = One Up Bond F < phosphoric acid etching only.

Conclusion: Long-term water storage significantly increased the microleakage of Helioseal F applied alone and with a bonding agent. Regardless of the storage term, the use of etch-and-rinse adhesives resulted in significantly less microleakage compared to that achieved with self-etching adhesives or acid etching alone. The sealants placed without a prior bonding agent showed the greatest amount of leakage after four years.