Ecomet 4 automet 2

Ultrastructural observations of resin cement/bock material interfaces were conducted after embedding bonded specimens in epoxy resin (Epon812, Nisshin EM, Tokyo, Japan), and incubating them at 37°C for an additional 12 h. Embedded specimens were sectioned, and surfaces of cut halves were polished using a grinder-polisher (Ecomet 4/Automet 2, Buehler) with #600, #1200, and then #4000 grid silicon carbide papers. Surfaces were finally polished on a special soft cloth using diamond paste down to 0.25 μm particle size (DP-Paste, Struers, Ballerup, Denmark). These surfaces were then subjected to argon-ion beam etching (Type EIS-200ER, Elionix, Tokyo, Japan) for 30 s with the ion beam (accelerating voltage, 1.0 kV; ion current density, 0.4 mA/cm 2 ) directed perpendicular to the polished surface. Surfaces were finally coated in a vacuum evaporator (Quick Coater Type SC-701, Sanyu Electron, Tokyo, Japan) with a thin film of gold and were observed using a SEM instrument (ERA-8800FE, Elionix) at an accelerating voltage of 10 kV.

The resin-dentin interface was ultrastructurally observed by scanning electron microscopy (SEM). Bonded specimens from each group (n=5) were stored in distilled water maintained at 37ºC for 24 h, embedded in self-curing epoxy resin (Epon812, Nisshin EM, Tokyo, Japan), and stored at 37ºC for an additional 12 h. The embedded specimens were sectioned through the diameter of the composite resin post, and the surfaces of the cut halves were polished with an Ecomet 4/Automet 2 (Buehler) using SiC papers with a grit size of 600, 1,200, and 4,000 in succession. The surface was finally polished by a soft cloth using diamond paste (Buehler) with a grit size of 1.0 lm. All SEM specimens were dehydrated in ascending concentrations of tert-butanol (50% for 20 min, 75% for 20 min, 95% for 20 min, and 100% for 2 h) and transferred to a critical-point dryer for 30 min. These surfaces were subjected to Argon ion-beam etching (Type EIS-200ER, Elionix, Tokyo, Japan) for 30 s, with the ion beam (accelerating voltage, 1.0 kV, ion current density, 0.4 mA/cm 2 ) directed perpendicularly to the polished surface. Surfaces were coated in a vacuum evaporator (Quick Coater Type SC-701, Sanyu Denshi, Tokyo, Japan) with a thin film of gold and observed by SEM (ERA 8800FE, Elionix) at an accelerating voltage of 10 kV. All of the specimens were observed under SEM.