Figure 2

Live/dead staining of 2-day dental plaque microcosm biofilms on the composites. Live bacteria were stained green, and dead bacteria were stained red. Live and dead bacteria in proximity resulted in yellow/orange colours. The control composite was covered by a thick biofilm with green staining. NACP composites containing QADM and NAg had much more dead bacteria. There was little difference in biofilm appearance vs ageing time, indicating that the antibacterial activity was not lost during water-ageing. NACP, nanoparticles of amorphous calcium phosphate; NAg, nanoparticles of silver; QADM, quaternary ammonium dimethacrylate.