SEM observations of the HGFs on the control and plasma treatment surfaces.

<p>SEM images of HGFs on zirconia disks at 3 h (A) and 24 h (B) of culture. Helium APDBD plasma treated for 30 s (a, e). Helium APDBD plasma treated for 60 s (b, f). Helium APDBD plasma treated for 90 s (c, g). Surfaces without helium APDBD plasma treatment (d, h). High magnification (a-d), scale bar = 20 μm. Low magnification (e-h), scale bar = 200 μm.