Nova 230 nano sem

Titanium test specimens in rectangular plate form (14 mm × 6 mm, 2 mm in thickness) were machined from commercially pure grade 4 titanium and grade 5 Ti-6Al-4V alloy (Figure 10A). To modify the surface from machine-smooth to microroughened, grade 4 commercially pure titanium plates were sandblasted and acid-etched. All test specimens were prepared and provided by DIO (Busan, Korea). Surface morphology was examined using scanning electron microscopy (SEM; Nova 230 Nano SEM; FEI, Hillsboro, Oregon). The hydrophilicity/hydrophobicity of titanium surfaces with and without UV treatment was evaluated by measuring the contact angle of 3 mL of ddH₂O.

The surface morphology of titanium specimens was qualitatively examined by scanning electron microscopy (SEM; Nova 230 Nano SEM, FEI, Hillsboro, OR, USA). In addition, roughness was quantified using an optical profile microscope (MeX, Alicona Imaging GmbH, Raaba, Graz, Austria) to measure the average roughness (Sa) and peak-to-valley roughness (Sz). The hydrophilicity/hydrophobicity or wettability of specimen surfaces was evaluated by measuring the contact angle of 3 µL of ddH₂O in most experiments. To examine the effect of water volume, the contact angle was also measured with 1, 5, 10, and 20 µL ddH₂O.

To evaluate a substantial cell retention force to titanium surfaces, we performed cell detachment assays. After 24 h of incubation, cultures were rinsed with PBS twice and then moved to new culture plates. Half of the disks were agitated (amplitude 10 mm; frequency 30 Hz) in 0.025% Trypsin solution, for 10 min, to detach cells from the surface, while the other half were statically incubated for 10 min. The numbers of cells were colorimetrically measured, using WST-1 reagent. Cell retention rate was calculated as [(remaining cell on the disks after detachment)/(remaining cell on the statically cultured disks)] × 100 (%). Cells were observed by using a scanning electron microscope (SEM; Nova 230 NanoSEM; FEI, Hillsboro, OR, USA) before and after detachment, as previously described [27 (link)].

Titanium test specimens in rectangular plate form (14 mm × 6 mm, 2 mm thickness) were machine-milled from commercially pure grade 4 titanium and grade 5 Ti-6Al-4V alloy (Figure 1A). Poly(methyl methacrylate) (PMMA) acrylic resin specimens were also fabricated. Surface morphology of these test specimens was examined by scanning electron microscopy (SEM; Nova 230 Nano SEM, FEI, Hillsboro, Oregon). The hydrophilicity/hydrophobicity of test surfaces with and without UV treatment were evaluated by measuring the contact angle of 3 µL of ddH₂O.

Five different test materials in rectangular plate form (6 mm × 14 mm, 2 mm thick) were prepared (Figure 1A, Table 1). Bis-acrylic, composite, and self-curing acrylic were prepared using standardized silicone molds prepared for each material and according to the manufacturer’s instructions. Milled acrylic plates were designed using CAD software (123D Design, Hyperdent^®, Synergy Health, Sydney, Australia) and machined from PMMA disks with a milling machine (Versamill 5 × 200, Axsys Dental Solutions, Wixom, MI, USA). Acrylic plates were washed with a steam cleaner and disinfected with 75% ethanol. Machined Ti alloy plates were manufactured as a positive control. Surface topography was examined by scanning electron microscopy (SEM; Nova 230 Nano SEM, FEI, Hillsboro, OR, USA).

Thin and round commercially available pure Ti fibers (99.6%, Sigma-Aldrich, St. Louis, MO, USA), 125 µm in diameter, 2000 mm long were woven together to form disks approximately 10 mm in diameter and 1 mm thick.
To roughen some of the samples, scaffolds were introduced by acid-etching with 67% (w/w) H₂SO₄ (Sigma) at 120 °C for 10 s. The diameters and thicknesses of the original and acid-etched samples were calculated using ImageJ program (NIH, Bethesda, ML, USA). The diameters and thicknesses were then used to calculate the total volumes of the scaffolds. The porosity of untreated scaffolds was calculated by subtracting the Ti microfiber volume from the total volume. The porosity of the acid-etched scaffolds was calculated by comparing their weight ratio to those of the untreated scaffolds. The samples were autoclaved, and then placed and stored at a dark condition for four weeks to obtain biological aging. The surface morphologies of the Ti microfibers were examined by SEM (Nova 230 Nano SEM, FEI, Hillsboro, OR, USA). The minimum and maximum pore sizes of the Ti microfibers were determined by measuring 30 pores in the image. Photofunctionalization was performed by treating Ti microfiber scaffolds with UV light for 15 min using a photo device (TheraBeam Affiny; Ushio Inc, Tokyo, Japan) immediately before use.