Vega 3 sb

The selected bonded sticks were immersed in ammoniacal silver nitrate solution in darkness for 24 h, rinsed thoroughly in distilled water, and immersed in photo-developing solution for 8 h under a fluorescent light to reduce silver ions into metallic silver grains within voids along the bonded interface (Tay et al., 2002) . Sticks were polished with a wet 600-, 1000-, 1200-, 1500-, 2000-and 2500-grit SiC paper and 1 and 0.25 µm diamond paste (Buehler, Lake Bluff, USA) using a polishing cloth. The specimens were then ultrasonically cleaned, air dried, mounted on stubs, and coated with carbon (MED 010, Balzers Union, Balzers, Liechtenstein). The resin-dentin interfaces were analyzed using a field-emission scanning electron microscope operated in the backscattered mode (VEGA3 SB, TESCAN ORSAY HOLDING, Warrendale, PA, USA).
Three images were captured from each resin-dentin bonded stick. The relative percentage of NL within the adhesive and hybrid layers in each specimen was measured in all images using the public domain Image J software, a Java-based image processing software package developed at the National Institutes of Health (NIH) (Schneider et al. , 2012) by a blinded researcher (Reis et al., 2007) . The mean NL of all sticks from the same tooth was averaged for statistical purposes.