Inactivation of Oral Biofilms Using Visible Light and Water-Filtered Infrared a Radiation and Indocyanine Green

Abstract

Aim: To investigate the antimicrobial photodynamic therapy (aPDT) of visible light and water-filtered infrared A radiation in combination with indocyanine green (ICG) on planktonic oral microorganisms as well as on oral biofilm. Methods: The irradiation was conducted for 5 min in combination with ICG. Treatment with chlorhexidine served as a positive control. The number of colony forming units and bacterial vitality were quantified. Results: All tested bacterial strains and salivary bacteria were killed at a level of 3log10. The colony forming units of the initial mature oral biofilms were strongly reduced. The high bactericidal effect of aPDT was confirmed by live/dead staining. Conclusion: The aPDT using visible light and water-filtered infrared A radiation and ICG has the potential to treat periodontitis and peri-implantitis.

Microbial Composition of Oral Biofilms after Visible Light and Water-Filtered Infrared a Radiation (VIS+wIRA) in Combination with Indocyanine Green (ICG) as Photosensitizer

“…Numerous studies have already reported high rates of reduction in viable microorganisms by aPDT of oral biofilms using VIS+wIRA in combination with photosensitizers such as toluidine blue (TB) and chlorine e6 (Ce6) [ 23 , 28 ]. Similar promising results regarding the number of surviving bacteria were also achieved in a recent study with the photosensitizer indocyanine green (ICG) [ 29 ]. This anionic photosensitizer is characterized by low toxicity, good tolerance and rare occurrence of side effects [ 30 ].…”

“…In contrast to the other studies with ICG, the biofilm examined was generated in situ on bovine enamel slabs and subjected to aPDT ex vivo. A previous study showed that VIS+wIRA in combination with ICG significantly reduced the number of planktonic bacteria within human saliva as well as the viable counts of oral microorganisms within initial adhesion and mature oral biofilms [ 29 ]. In the present study, the aim was to investigate whether aPDT with VIS+wIRA as the light source and ICG as the photosensitizer is able to change the diversity of living bacteria in the biofilm and to influence their microbial balance.…”

“…In addition to the bacteria-eliminating effect of ICG reported in an earlier study, the influence of aPDT on the composition of the oral biofilm could be also meaningful for the adjunctive treatment of periodontitis and peri-implantitis [ 3 , 4 , 5 , 29 ]. In the untreated initial biofilm, numerous bacterial species were identified, and can be summarized in 11 bacterial genera.…”

“…Each dilution was plated onto CBA and HCB plates followed by cultivation in an incubator (Heracell™ 150, Thermo Fisher Scientific Inc., Waltham, MA, USA) at 37 °C under aerobic conditions and anaerobic conditions using airtight reagent containers (Anaerocult ® A, Merck, Darmstadt, Germany). The subsequent quantification of the cultured microorganisms was carried out by visual determination of the CFU on the plates using a colony counter (WTW BZG 40, Xylem Analytics Germany Sales, Weilheim, Germany) and was part of a previous study [ 29 ].…”

Daily Administered Dual-Light Photodynamic Therapy Provides a Sustained Antibacterial Effect on Staphylococcus aureus

“…Thus, the depth of penetration might be increased when compared to other photosensitizers. [25]. APDT with ICG has previously shown a significant antibacterial action against S. aureus, studied in the methicillin-resistant strains [26].…”