International Journal of Preventive Medicine (Int J Prev Med)2008-780252201401141715EN20140114<strong>Background:</strong>Marginal seal has a principal role in durability and <br />clinical success offissure sealants. The aim of this study was to compare the microleakage of two materials used as pit and fissure sealant with different methods of application.<br /><strong>Methods:</strong>The 55 extracted premolars were assigned randomly to <br />one ofthe following five groups: Group 1: Acid-etching (ultra-etch) + fissure sealant (conventional method), Group 2: Acid etching + bonding agent (single bond) + fissure sealant, Group 3: Self-etching primer + bonding agent (SE bond) + fissure sealant, Group 4: Acid-etching + bonding agent + flowable composite (Filtek flow), Grope 5: Self-etching primer + bonding agent + flowable composite. Following sealant placement, the teeth were thermocycled (3000 cycles; 5-55&deg;C) and then immersed in 50% silver nitrate solution for 24 h and then immersed in photo developing solution for 4 h under fluorescent light. The teeth were then sectioned in a bucco-lingual direction. Microleakage was scored using a stereomicroscope and a 4-criteria ranking/ordinal scale. Data were analyzed statistically using the Kruskal-Wallis and Mann-Whitney tests.<br /><strong>Results:</strong>The result of tests showed that there were statistical <br />differences between some groups. Groups 2 and 4 had the lowest and Groups 3 and 5 had the highest microleakage scores and a statistically significant difference could be displayed between them (P&lt; 0.05). Mean microleakage in Group 4 was also significantly lower than in Group 1 (P&lt; 0.05).<br /><strong>Conclusions:</strong>Using acid and a bonding agent prior to sealant <br />placement seems to be the best technique for sealing pits and fissures.<br /><strong>Keywords:</strong>Bonding agent, fissure sealant, flowable composite, <br />microleakagehttp://ijpm.mui.ac.ir/index.php/ijpm/article/view/1295http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1295/1356