Resin based composite considers substantially as a restorative material in clinic. Dentists concern in placement resin composite restorations with Long term survival. Materials and Methods: 20 Non carious human third molars, class I cavity was prepared in every molar, restored with methacrylate resin composite Tetric EvoCeram. The restored teeth were subjected to thermocycles. Specimen was randomly divided into two groups : the first group 10 restorations, were repaired by Cojet® (3M ESPE, Germany) and restored by Filtek™ P90, the second group 10 restorations also repaired by Cojet ® but restored by Filtek™ Z350 XT. After that all teeth were subjected to thermocycles again, later immersed in 0.5% basic fuchsin solution for 1 s. The teeth were transversely sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed. Results: No statistically significant differences in microleakage were observed between two groups either with low shrinkage Silorane resin composite or methacrylate resin composite