The purpose of the present study was to evaluate the efficacy of chlorhexidine, ultrasonic and
photodynamic therapy against E.faecalis in dental root canals, Sixty teeth were used in this study.
The crowns were decapitated and the root canals were biomechanically prepared using step-back
technique, root canals were inoculated with E.faecalis (ATCC 292 12) for 2 days. Teeth were
divided into three main experimental groups, twenty teeth each, according to the method of intra
canal treatment. Group (I), chlorhexidine, Group (II), ultrasonic + chlorexidine, while Group
(III), photodynarnic therapy (Asptim), in group I: Teeth in that group were irrigated with 2%
chlorhexidine solution. for 2 minutes, Each root canal used two chx consepsis which were introduced
via the syringe needle, in group II: Teeth in that group were irrigated with a combination between
ultrasonic + 2% chlorhexidine solution, 2% chlorhexidine solution was introduced directly via the
syringe needle, An ultrasonic tip activated by ultrasonic device (Satelec, France) was placed in the
canals, in group III: Teeth in that group were treated by photodynamic therapy (PDT) (laser + photo
sensitizer agent), (PDT solution: i.e. tolonium chloride) a vital stain was added to fill the canals, A
low power laser diode (Aseptim) (660nm) was applied on the photosensitizer for 2 minutes through
an optical fiber handpiece, Power was set at 100 mw and irradiation time was 2 minutes, The
handpiece was gently moved up and down in the canal during irradiation.Antibacterial efficacy was
assessed before and after treatment. These samples were cultured on KF streptococcus agar media,
incubated for two days then colony forming units were counted. Under the experimental conditions
tested, the antibacterial efficacy of photodynamic therapy against E.faecalis provided a better effect
than chiorhexidine or ultrasonic + chlorhexidine. However there was no statistically significant
difference among the different groups. All the tested materials were effective, 2% Chlorhexidine
reduced E.faecalis by 99.69%, while chlorhexidine & ultrasonic reduced bacteria by 99.71% and
the photodynamic therapy (low power diode laser) with output power 100mw for 2 min possess an
excellent antibacterial efficacy by 99.69%. PDT was effective for reducing E.faecalis in root canals
and could be an adjunct to endodontic treatment.