Methods: 60 extracted human premolars were randomly divided into two groups and each group was divided to three subgroups of 10 teeth. In Group 1, Subgroup 1 after prophylaxis, enameloplasty, etching of occlusal surfaces with 38% phosphoric acid gel, rinsing and Drying, low viscosity sealant was applied and cured. Group 1, Subgroup 2 received enamel bonding agent prior to low viscosity sealant placement and cured. In Group 1, Subgroup 3 before low viscosity sealant placement, dentin bonding agent was applied and cured. In Group 2 similar procedures were performed except for applying high viscosity sealant. Specimens were thermocycled for 500 cycles (5°C - 55°C) with dwell time of 10 second. Microleakage was scored according to distance of dye penetration as: 0 = no dye penetration and 3 = dye penetrates to underlying fissure.
Results: Statistical Analysis showed significant effect of sealant viscosity and bonding agent on the microleakage scores (P=0.037). There was no significant difference between dentin bonding agent and enamel bonding agent and no bonding agent subgroups in the microieakage scores in both groups. Significant differences between low viscosity sealant without applying bonding agent subgroup and high viscosity sealant without applying bonding agent subgroup (P=0.041), and between dentin bonding agent in low viscosity and high viscosity sealant subgroups (P=0.002) were found.
Conclusions: The results of this study indicated that concurrent use of low viscosity sealant and dentin bonding agent reduces the microleakage of pit and fissures.