New Irradiation Method with Indocyanine Green-Loaded Nanospheres for Inactivating Periodontal Pathogens

Abstract

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive strategy for periodontitis treatments. However, use of aPDT for periodontal treatment is complicated by the difficulty in accessing morphologically complex lesions such as furcation involvement, which the irradiation beam (which is targeted parallel to the tooth axis into the periodontal pocket) cannot access directly. The aim of this study was to validate a modified aPDT method that photosensitizes indocyanine green-loaded nanospheres through the gingivae from outside the pocket using a diode laser. To establish this trans-gingival irradiation method, we built an in vitro aPDT model using a substitution for gingivae. Irradiation conditions and the cooling method were optimized before the bactericidal effects on Porphyromonas gingivalis were investigated. The permeable energy through the gingival model at irradiation conditions of 2 W output power in a 50% duty cycle was comparable with the transmitted energy of conventional irradiation. Intermittent irradiation with air cooling limited the temperature increase in the gingival model to 2.75 °C. The aPDT group showed significant bactericidal effects, with reductions in colony-forming units of 99.99% after 5 min of irradiation. This effect of aPDT against a periodontal pathogen demonstrates the validity of trans-gingival irradiation for periodontal treatment.

Photoelimination Potential of Chitosan NanoparticlesIndocyanine Green Complex Against the Biological Activities of Acinetobacter baumannii Strains: A Preliminary In Vitro Study in Burn Wound Infections

“…Also, Sasaki et al estimated the efficiency of using ICG-loaded Nanospheres coated with chitosan as a photosensitizer with an 810 nm diode laser and confirmed the improved result by this method. 27 As mentioned before, the reason of this evidence is that the ICG photosensitizer has a negative charge, so being encapsulated in Nanoparticles like chitosan, which is an inexpensive, non-toxic, biodegradable, naturally occurring cationic polysaccharide, would help ICG to attach easily to the bacterial cell membrane and increase the bactericidal effect of this photosensitizer. 24,25 There have been piles of studies on the bactericidal effect of ICG, ICG-aPDT or NCs@ICG-aPDT separately, but during our study, for the first time, the bactericidal effect of the ICG-aPDT group was compared with the NCs@ICG-aPDT group and interestingly, we figured out that NCs@ICG-aPDT was relatively more efficient.…”

“…There have been a lot of studies which have measured the efficiency of ICG-aPDT in its bactericidal aspect. [17][18][19][20][21][22][23][24][25][26][27] In an investigation by Omar et al, photo-activated ICG with light from a NIR laser was able to eradicate common burn wound pathogens. 17 In fact, this method has been estimated for different kinds of bacterial species, from periodontal pathogens to nosocomial ones, and in all of them, this method has been reported as an effective antibacterial method.…”

Laser-Assisted aPDT Protocols in Randomized Controlled Clinical Trials in Dentistry: A Systematic Review

“…Regarding the use of trans-gingival as an aPDT, as applied in studies [ 36 , 38 ] evaluated here, such a therapy may be considered a novel approach, and this approach appears to be able to bypass the limitation of light in accessing complex target areas, such as root furcations or deep periodontal pockets [ 76 , 77 ]. It is known that the penetration depth of the 660 nm wavelength is 3–3.5 mm, while that for the range of 800–900 nm is 6–6.5 mm [ 76 ].…”

Impact of Molar Furcations on Photodynamic Therapy Outcomes: A 6-Month Split-Mouth Randomized Clinical Trial

“…The fact that molar furcation sites did not respond to PDT compared to other sites may also be due to their clinical characteristics. The difficulty to place the photosensitizer as well as the activating light source in deep inter-radicular defect due to their horizontal and vertical components and the straight morphology of pocket tip could influence PDT efficacy [47]. The impact of horizontal/degree furcation involvement has been mainly demonstrated for tooth loss [9][10][11][12].…”