Fig. 1.

Scanning electron microscope (SEM) images of multispecies endodontic biofilms. Multispecies bacteria were successfully impregnated into the interior of the sterile dentin blocks after incubation for 1 day. After the 3-week incubation, the mature biofilm exhibited a layered structure of bacterial aggregates covering the dentin surface. The mature multispecies biofilms were treated with saline, saturated calcium hydroxide solution (CH), 2% chlorhexidine solution (CHX) or NAC at the indicated concentrations for 7 days and then observed using SEM at a magnification of 20,000× and 100,000× (inset) operating at 10 kV.