Photodynamic Inactivation of an Endodontic Bacteria Using Diode Laser and Indocyanine Green-Loaded Nanosphere

Apical periodontitis, an inflammatory lesion causing bone resorption around the apex of teeth, is treated by eradicating infectious bacteria from the root canal. However, it has a high recurrence rate and often requires retreatment. We investigated the bactericidal effect of antimicrobial photodynam...

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Bibliographic Details
Main Authors: Naoya Higuchi, Jun-ichiro Hayashi, Masanori Fujita, Yuki Iwamura, Yasuyuki Sasaki, Ryoma Goto, Tasuku Ohno, Eisaku Nishida, Genta Yamamoto, Takeshi Kikuchi, Akio Mitani, Mitsuo Fukuda
Format: Article
Language:English
Published: MDPI AG 2021-08-01
Series:International Journal of Molecular Sciences
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Online Access:https://www.mdpi.com/1422-0067/22/16/8384
Description
Summary:Apical periodontitis, an inflammatory lesion causing bone resorption around the apex of teeth, is treated by eradicating infectious bacteria from the root canal. However, it has a high recurrence rate and often requires retreatment. We investigated the bactericidal effect of antimicrobial photodynamic therapy (aPDT)/photodynamic antimicrobial chemotherapy (PACT) using indocyanine green (ICG)-loaded nanospheres coated with chitosan and a diode laser on a biofilm of <i>Enterococcus faecalis</i>, a pathogen of refractory apical periodontitis. Biofilm of <i>E. faecalis</i> was cultured in a porcine infected root canal model. ICG solution was injected into the root canal, which was then irradiated with a laser (810 nm wavelength) from outside the root canal. The bactericidal effect was evaluated by colony counts and scanning electron microscopy. The result of the colony counts showed a maximum 1.89 log reduction after irradiation at 2.1 W for 5 min. The temperature rise during aPDT/PACT was confirmed to be within a safe range. Furthermore, the light energy transmittance through the root was at a peak approximately 1 min after the start of irradiation, indicating that most of the ICG in the root canal was consumed. This study shows that aPDT/PACT can suppress <i>E. faecalis</i> in infected root canals with high efficiency.
ISSN:1661-6596
1422-0067