Effects of sub-lethal doses of photo-activated disinfection against Porphyromonas gingivalis for pharmaceutical treatment of periodontal-endodontic lesions.
BACKGROUND
Microorganisms treated by photo-activated disinfection (PAD) in combined periodontal-endodontic (perio-endo) lesions would be exposed to sub-lethal doses of PAD (sPAD). This study evaluated the effect of sPAD using toluidine blue O (TBO) in combination with diode laser irradiation on the growth and biofilm-formation ability of Porphyromonas gingivalis as an endo-periodontal pathogen.


METHODS
The antibacterial and antibiofilm potential of sPAD against P. gingivalis was analyzed at sub-lethal doses of TBO and irradiation time of diode laser on a colony-forming unit and crystal violet assays, respectively.


RESULTS
TBO-mediated PAD, using 6.25-100μg/mL at a fluency of 171.87J/cm2and 12.5-100μg/mL at a fluency of 137.5J/cm2, showed a significant dose-dependent reduction in P. gingivalis growth when compared to the control. TBO-mediated PAD showed a significantly inhibitory effect on biofilm formation in P. gingivalis than TBO-PAD at sub-lethal levels.


CONCLUSIONS
High doses of sPAD revealed antibacterial and antibiofilm potential activity, whereas lower doses of sPAD had conflicting results. Therefore, when PAD is prescribed in combined perio-endo lesions treatment, the dose of PAD used in vivo should be taken into account.
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Maryam
M
Pourhajibagher
Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Nasim
N
Chiniforush
Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran; Innovative Research Center, Islamic Azad University, Mashhad Branch, Mashhad, Iran.
Reza
R
Raoofian
Private Practice, Tehran, Iran.
Roghayeh
R
Ghorbanzadeh
Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Sima
S
Shahabi
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: abahador@sina.tums.ac.ir.
Abbas
A
Bahador
D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D010518:Periodontitis / Q000188:drug therapy / Q000382:microbiology; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000528:radiation effects*; D011671:Pulpitis / Q000188:drug therapy / Q000382:microbiology
D017319:Photosensitizing Agents
Biofilm formation; Endo-periodontitis; Photo-activated disinfection; Porphyromonas gingivalis; Toluidine blue O