Methods: Standard Class V cavities (5x2x1.5mm) were prepared at the cemento-enamel junction on the buccal and lingual surfaces of 40 sound human molars (n=80). Teeth were randomly distributed into two groups; Group 1: the cavities were restored according to manufacturers' instructions with a nano ceramic composite (CeramX Duo, Dentsply), Group 2: with a light curing nanofilled resin-modified glass ionomer (Ketac N100, 3M ESPE) (n=40).Following finishing and polishing procedures, the specimens were distributed into four subgroups according to the application of surface sealants: a-Negative control (without use of any sealant); b-Positive control, XP Bond (Dentsply); c-G Coat Plus (GC); d- Top Coat (Kuraray). Samples were stored in distilled water for 24 hours at 37 0C and thermocycled. They were then, isolated with nail polish, immersed in 0.5% aqueous basic fuchsin dye solution for 24 hours and sectioned longitudinally in bucco-lingual direction. The slices were observed under a stereomicroscope by two examiners and dye penetration scores were recorded. The microleakage scores obtained from the enamel and dentin margins were analized with Chi-Square test (p=0.05).
Results: No microleakage was observed at enamel and dentin margins on groups sealed either with G Coat Plus or with Top Coat. Ketac N100 without sealant and Ketac N100 sealed with XP Bond groups revealed the highest microleakage scores at enamel margins (p<0.05). The differences among the groups at dentin margins were not significant (p>0.05). No significant differences were found between enamel and dentin margins at any groups (p>0.05).
Conclusion: The microleakage of nano ceramic composite restorations did not differ with the application of surface sealants The application of surface sealant could eliminate microleakage at the enamel for nanofilled resin-modified glass ionomer restorative materials.