Photodynamic Therapy as an Alternative for Root Canal Disinfection

Objectives: The aim of this study was to evaluate in vitro the antimicrobial effect of Photodynamic therapy (PDT), light activated disinfection system (LAD) and three irrigation solutions (NaOCl, CHX, H₂O₂) on root canals infected with Enterococcus faecalis . Methods: Extracted single rooted human teeth were instrumented and autoclaved, afterwards inoculated with Enterococcus faecalis (ATCC 6057) for 1 hour. The teeth were divided in 8 groups (n=8x20): (a) Untreated control group, (b) PDT group treated with methylen blue and soft laser irradiation (λ=670 nm) for 60 seconds, (c) LAD-Group treated with toluidin blue and LED light irradiation (λ=670 nm) for 60 seconds, (d) 5 ml NaOCl (1%) solution , (e) 5 ml NaOCl (3%) solution, (f) 5 ml CHX (0.12%) solution, (g) 5 ml CHX (2%) solution and (h) 5 ml H₂O₂ (3%) solution. Subsequently each tooth was placed in NaCl solution (0,9%), sonicated for 2 minutes and shaked for 1 minute, in addition the collective solutions were cultivated in petri dishes for 24 hours. Results: The control group showed 10⁶ cfu/mL on average. The bacterial reduction in the treated groups was as follows: b=98,18%, c=88,97%, d=99,99%, e=100%, f=99,52%, g=99,71% and h=99,99%. Conclusions: The PDT and LAD could be developed as an adjunctive procedure to conventional root canal treatment. Complete elemination of test germ was only observed in 3% sodium hypochloride and it had the most antimicrobial effect in reduction of E. faecalis and could be regarded furthermore as the golden standard for endodontic treatments.