The in Vitro Antimicrobial Efficacy of PDT against Periodontopathogenic Bacteria

Abstract

Periodontitis, an inflammatory disease, is caused by biofilms with a mixed microbial etiology and involves the progressive destruction of the tooth-supporting tissues. A rising number of studies investigate the clinical potential of photodynamic therapy (PDT) as an adjunct during active therapy. The aim of the present review was to evaluate the available literature for the in vitro antimicrobial efficacy of photodynamic therapy focusing on the periodontopathogenic bacteria Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. The focused question was: “Is it possible to decrease (at least 3 log steps or 99.9%) or even eliminate bacterial growth by photodynamic therapy in vitro when compared to untreated control groups or control groups treated by placebo?” In general, PDT resulted in a substantial reduction of surviving bacteria. However, not all studies showed the desired reduction or elimination. The ranges of log10-reduction were 0.38 (58%) to a complete eradication (100%) for P. gingivalis, 0.21 (39%) to 100% for A. actinomycetemcomitans and 0.3 (50%) to 100% for F. nucleatum. In conclusion, further and particularly more comparable studies are needed to evaluate if PDT can be clinically successful as an adjuvant in periodontal therapy.

In vitro effect of diode laser against biofilm of Aggregatibacter actinomycetemcomitans

“…[ 14 ] Its presence is considered a risk marker for the progression of attachment loss. [ 15 ] Since the elimination of bacteria is important to delay subgingival recolonization, many approaches including the use of antibiotics[ 16 ] or antimicrobial photodynamic therapy (PDT)[ 17 18 ] have been introduced. However, these bacteria can resist such therapeutic procedures as shown by the reduced antibiotic susceptibility.…”

“…[ 16 ] Regarding PDT, not all studies could decrease bacteria by at least 3 log CFU/mL (99.9%). [ 17 ]…”

“…[ 22 ] However, the results vary depending on the type and concentration of photosensitizer as well as the incubation time for the photosensitizer to reach its target. [ 17 ] Mattiello et al . [ 23 ] studied an in vitro photodynamic effect using 0.01% toluidine blue-O for 5 min and an AlGaInP diode laser for 3 min on A. actinomycetemcomitans and S. sanguinis inoculums and found a 61.53% reduction of the CFU counts for A. actinomycetemcomitans .…”

Engineering Polymeric Nanosystems against Oral Diseases

“…With respect to the disinfection of the root canal system, the emerging approach of antimicrobial photodynamic therapy (aPDT) shows good promise. The aPDT is based on the use of a photosensitising agent (a photosensitiser), which can be preferentially localised in certain tissues and subsequently activated by light of the appropriate wavelength in the presence of oxygen to generate cytotoxic reactive oxygen species (ROS) for the target microorganism [ 108 , 135 ]. An advantageous combination of aPDT with NPs, as mentioned above, relies on the fact that the phototoxicity of the photosensitiser agent is quenched when incorporated in the NPs, whilst it is regained when it gets released.…”

Polymeric Nanoparticle-Based Photodynamic Therapy for Chronic Periodontitis in Vivo

“…The main advantages of aPDT over conventional antimicrobial therapies include the immediate onset of action, elimination of resistant microorganisms and secreted virulence factors, local delivery of PS, and double selectivity (deleterious effect only on sites where both PS and light are delivered concomitantly) [ 8 ]. The adjunctive use of aPDT in the treatment of periodontitis has been suggested as an alternative to chemical antimicrobial agents for elimination of subgingival species [ 9 ]. However, although it has been proven effective in a few clinical trials [ 10 , 11 , 12 , 13 ], aPDT beneficial effects over SRP alone are not evident in single sessions, as supported by a recent meta-analysis [ 14 ].…”