A total of 42 specimens (21 specimens of each restorative material) were fabricated using a customized cylindrical rubber base mould (10 × 2 mm). The resin composites were placed using a plastic instrument and covered with a mylar strip. A 1-2 mm thick glass slide was placed over the strip before curing with the light activating source (tungsten-halogen lamp, Trilight, 3M, ESPE, Seefeld, Germany) to flatten the surfaces. The samples were then cured for 40s through the mylar strips and the glass slide. The curing light intensity was measured at 800mW/cm2 and monitored using a built-in radiometer. An additional 20 s curing was done on both the sides of the specimens after removing the strips and glasses. The cured samples were then stored in 100% humidity at 37°C for 24 h prior to the finishing procedures.