Dp paste

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.

Representative restorative/tooth interfaces were observed via SEM (ERA-8800FE, Elionix, Tokyo, Japan). Bonded specimens stored in 37ºC distilled water for 24 h were embedded in epoxy resin (Epon 812, Nisshin EM, Tokyo, Japan) and then longitudinally sectioned with a precision sectioning saw (IsoMet 1000 Precision Sectioning Saw). The resin/tooth interfaces' sectioned surfaces were polished to a high gloss using abrasive disks (Fuji Star Type DDC), followed by diamond pastes down to 0.25 μm in particle size (DP-Paste, Struers, Ballerup, Denmark); this was followed by ultrasonic cleaning for 30 min. The interface and treated surface specimens were dehydrated in ascending grades of tertbutyl alcohol (50% for 20 min, 75% for 20 min, 95% for 20 min, and 100% for 2 h) and transferred to a freeze dryer (Model ID-3, Elionix) for 30 min. The resin/tooth interface specimens were subjected to argon-ion beam etching (EIS-200ER, Elionix) for 45 s with the ion beam (accelerating voltage 1.0 kV, ion current density 0.4 mA/ cm 2 ) directed perpendicular to the polished surfaces. Finally, all the SEM specimens were coated with a thin film of gold in an automatic ion sputter (Quick Coater Type SC-701, Sanyu Electron, Tokyo, Japan). The observations were carried out using an SEM at an operating voltage of 10 kV.

The specimens were polished to a high gloss with SiC papers (Fuji Star Type DDC) and with a series of diamond pastes of minimum particle size 0.25 µm (DP-Paste, Struers, Ballerup, Denmark). The mirror-polished surfaces were further subjected to argon-ion beam etching (IIS-200ER, Elionix, Tokyo, Japan) for 40 s, with the ion beam perpendicular to the polished surface at an accelerating voltage of 1 kV and an ion current density of 0.4 mA/cm 2 . Subsequently, the surfaces were coated with a thin gold film in a Quick Coater vacuum evaporator (Type SC-701, Sanyu Electric, Tokyo, Japan). Observations were performed using field emission SEM (FE-8000, Elionix) at an operating voltage of 10 kV.
Representative wear facets of the tested resin composites were chosen as targets for SEM examinations. The specimens were randomly selected after performing the wear measurements, and the samples were evaporation-coated using the same procedure as for the polished specimens. The coated surfaces were visualized using SEM with an operating voltage of 10 kV.

Cured provisional resin specimens were polished to a high gloss with abrasive discs (Fuji Star Type DDC) followed by a series of diamond pastes down to a particle size of 0.25 µm (DP-Paste, Struers, Ballerup, Denmark). The polished surfaces were then subjected to argonion beam etching (IIS-200ER, Elionix, Tokyo, Japan) for 40 s, with the ion beam directed perpendicular to the polished surface (accelerating voltage=1 kV; ion current density=0.4 mA/cm 2 ). The surfaces were then coated with a thin film of gold in a Quick Coater vacuum evaporator (Type SC-701, Sanyu Denchi, Tokyo, Japan). Observations were conducted using a scanning electron microscope (SEM; FE-8000, Elionix) at an operating voltage of 10 kV and magnification of 10,000×.
SEM examinations were conducted on representative wear facets of the four provisional resin-based composites. The specimens were randomly selected after wear measurements, and evaporation coating of samples was performed in the same manner as the polished specimens. The coated surfaces were visualized using SEM with an operating voltage of 10 kV and magnifications of 50× and 2,500×.

Combined surfaces of enamel, dentin and resin composite were prepared as previously mentioned for the µSBS test. After the adhesive procedure, the light cured surfaces were covered with resin composite and further light cured for 40 s. All the specimens were stored in water at 37°C for 24 h. The filled specimens were sectioned perpendicularly to adhesive interface using a slow-speed diamond saw to obtain four slabs of 2 mm thickness for each adhesive. The specimens were then embedded in epoxy resin (Epoxicure Epoxy Resin, Buehler, IL, USA). The exposed adhesive interfaces of the combined enamel, dentin and composite resin substrates were sequentially polished with 600-, 800and 1000-grit SiC papers under running water. This was followed by polishing sequentially with 6 μm, 3 μm, 1 µm and 0.25 µm diamond pastes (DP-Paste, Struers, Copenhagen, Denmark), and cleaning with an ultrasonic device between each diamond paste polish. After drying, the specimens were mounted on brass tablets and sputter-coated with gold. The adhesive interfaces were then observed using SEM.

For each group, three teeth were prepared in the same manner as for the bond strength test, but without the plastic tubing. The specimens were longitudinally sectioned perpendicular to the bonded interface using a low-speed cutting machine and embedded in epoxy resin at room temperature. After 24 h, the cut surfaces were sequentially polished using 600-, 800-, 1000-, and 1200-grit abrasive paper and 0.5 µm diamond paste (DP-Paste, Struers). The specimens were etched with 10% phosphoric acid solution for 5 s, immersed in 5% sodium hypochlorite for 5 min, rinsed with distilled water, dried in an auto-desiccator cabinet for 3 days, sputter-coated with gold (SPI-Module Sputter Coater, SPI Supplies, West Chester, PA, USA) and analyzed under the SEM.