comparison of microleakage of two materials used as fissure sealants with different methods: an in vitro study

background: marginal seal has a principal role in durability and 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. methods: the 55 extracted premolars were assigned randomly to 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°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. results: the result of tests showed that there were statistical 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< 0.05). mean microleakage in group 4 was also significantly lower than in group 1 (p< 0.05). conclusions: using acid and a bonding agent prior to sealant placement seems to be the best technique for sealing pits and fissures.