ABSTRACT
Photodynamic therapy (PDT) has been proven to be effectivein disinfecting root canals. The aim of this present study wasto evaluate the effects of PDT on the viability of Enterococcusfaecalis using methylene blue (MB) and malachite green(MG) as photosensitizers. Solutions containing E. faecalis(ATCC 29212) were prepared and harvested by centrifugationto obtain cell suspensions, which were mixed with MBand MG. Samples were individually irradiated by the diodelaser at a distance of 1mm for 30, 60, or 120 seconds. Colonyformingunits (CFU) were determined for each treatment.PDT for 60 and 120 seconds with MG reduced E. faecalis viabilitysignificantly. Similar results were obtained when MBwas used as photosensitizer. PDT using MB and MG haveantibacterial effect against E. faecalis, showing potential tobe used as an adjunctive antimicrobial procedure in endodontictherapy...