Figure 3.

SEM. (a) Uniformly distributed E. faecalis biofilms on HA discs after the treatment of gas flow (He/(1%)O₂, 1 SLPM, 5 min) (the negative control). (b) Biofilms in the negative control group at higher magnification (20,000x): bacteria were adsorbed onto the HA surface and embedded in a self-produced extracellular matrix, as in a typical biofilm. (c) HA surface after direct plasma exposure (He/(1%)O₂ plasma, 5 SLPM, 5 min). (d) An area of the plasma-treated HA surface at higher magnification (20.000×): debris and fused cell bodies (arrow 1) were predominantly observed. Morphologically intact bacteria (arrow 2) were rarely spotted. (e) HA surface after treatment of 5.25% NaOCl for 5 min (the positive control). (f) Same biofilms of the positive control group at higher magnification (20.000×): most of the remaining bacteria appear morphologically intact (arrow 3). Deformed or fused cell bodies (arrow 4) were discernible but few.