This study aimed to investigate the effect of fluoride varnish on microleakage and the interfacial micromorphology of pit and fissure nano sealant after different etching times.
Materials and methods: One hundred freshly extracted third molars were used in this study. They were randomly allocated into control group (20 teeth) and test group (80 teeth) which was further subdivided into 4 subgroups each one contained (20 teeth) according to the etching time. Teeth of the test group were subjected to fluoride varnish application. The next day, each subgroup was acid etched according to its specific time (20, 40, 60, and 120 seconds for groups I, II, III and IV respectively). Nano fissure sealant was then applied to all teeth according to the manufacturer instructions. Teeth in the control group received the nano sealant without fluoride application. Ten teeth from each subgroup were used for interfacial micromorphology scanning, and the other
10 teeth were used for microleakage evaluation.
Results: The scanning electron microscopic examination revealed that the formed tags varied between the groups. The shortest tags were found in subgroup I (between 2.24-3.22 µm), while the largest were in subgroup IV (35.19- 35.24 µm). Score 0 microleakage was the significantly highest one in all groups. The comparison between test groups and control group revealed significant differences in score 1 and 3 only.
Conclusion: Application of fluoride did not affect the sealant application especially for the etching times 40 and 60 seconds.