Objectives . The aim of this study was to examine microleakage at the interface between pit-and-fissure sealants and enamel using micro-CT.

Materials and methods . Six extracted intact human molars were cleaned with prophylaxis paste in the region of pit and fissure. A sealant (Enamel Loc, Premier Dental) was applied in pits and fissures of all teeth. Three specimens were immersed in 50% silver nitrate solution for 24 h followed by exposure in fluorescent light for 8 h before being scanned in a micro-CT machine (X-tek). The other three were handled in the same way after undergoing 10,000 thermal cycles between 5 °C and 55 °C. The micro-CT images were evaluated in VGstudio Max software.

Results . The micro-CT images showed that silver nitrate was present at the interface between sealant and enamel indicating microleakage was present. Thermocycling increased microleakage at the sealant–enamel interface, as evident by increased amount of Ag present.

Conclusions . Micro-CT is a very useful nondestructive tool for the investigation of microleakage at the sealant–enamel interface. Thermocycling reduced the adhesion of sealants.