RESUMEN
To evaluate and compare the marginal leakage in class V cavities restored with three different tooth colored restorative materials using dye penetration system. Materials and methods: Thirty extracted premolars were randomly selected for this study. Standardized classV cavities were prepared and then divided into three equal groups. Group I was restored with nano filled composite, Group II was restored with hybrid composite and group III with polyacid modified composite. They were then subjected to thermo cycling, immersed in 2% methylene blue dye, sectioned and examined under stereomicroscope. Dye penetration for each section was recorded and data was analyzed. Results: Lowest micrileakage was recorded in group I and highest leakage recorded in Group III.Conclusion: Nanofilled composite resins provide a better sealing than hybrid and polyacid modified composites.