Antimicrobial photodynamic therapy using Indocyanine green and near-infrared diode laser in reducing Entrerococcus faecalis.
BACKGROUND
The use of Antimicrobial Photodynamic Therapy (aPDT) has been suggested as an adjuvant method to eliminate facultative bacteria during root canal disinfection. The purpose of this preliminary in vitro study was to determine whether the light-activated antimicrobial agent, Indocyanine green (ICG), could be used as photosensitizer and kill Enterococcus faecalis strain under planktonic conditions when irradiated with near-infared (NIR) diode laser emitting in 810nm wavelength.


METHODS
Planktonic suspension containing Enterococcus faecalis strain was divided into nine experimental groups: (1) aPDT with ICG and laser (medium energy fluence), (2) aPDT with ICG and laser (high energy fluence), (3) only ICG without laser activation, (4) only laser emission without ICG (5) 2.5% Sodium hypochlorite (NaOCl) as irrigant, (6) 2.5% NaOCl and aPDT with ICG and laser, (7) 2.0% Chlorhexidine gluconate (CHX) as irrigant (8) No treatment (positive control), (9) No bacterial biofilm growth (negative control). The samples were incubated for 7days and colony-forming units (CFUs) were determined to evaluate bacterial viability.


RESULTS
The microbiological test revealed that aPDT groups, regardless the overall power, showed significant lower mean log10CFU levels, than groups 3, 4 and 7 (p<0.01). The irrigation with 2.5% NaOCl and the combination of PDT and NaOCl achieved total elimination of bacteria.


CONCLUSIONS
These preliminary in vitro findings imply that the combination of ICG and NIR diode laser may be a novel supplement in aPDT and provide better disinfection during endodontic treatment.
Department of Endodontology, Aristotle University of Thessaloniki, School of Dentistry, 54124, Thessaloniki, Greece. Electronic address: hbeltes@gmail.com.
Charis
C
Beltes
Microbiology Department, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, 45110, Greece. Electronic address: isakkas@cc.uoi.gr.
Hercules
H
Sakkas
Department of Endodontology, Aristotle University of Thessaloniki, School of Dentistry, 54124, Thessaloniki, Greece. Electronic address: econom@dent.auth.gr.
Nikolaos
N
Economides
Microbiology Department, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, 45110, Greece. Electronic address: cpapadop@cc.uoi.gr.
Chrissanthy
C
Papadopoulou
D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D007208:Indocyanine Green / Q000494:pharmacology*; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*
D017319:Photosensitizing Agents; D007208:Indocyanine Green
Antimicrobial photodynamic therapy; Enterococcus faecalis; Root-canal therapy