Photo-sonodynamic antimicrobial chemotherapy via chitosan nanoparticles-indocyanine green against polymicrobial periopathogenic biofilms: Ex vivo study on dental implants.

Background: Antimicrobial photodynamic therapy (aPDT) is a treatment to deal with microorganisms, which is limited to treating microbial biofilms due to poor light penetration. Sonodynamic antimicrobial chemotherapy (SACT) can be used for circumventing the limitations of aPDT to inhibit the polymicrobial biofilms. The objective of this study has been focused on the simultaneous use of aPDT and SACT, which is called photo-sonodynamic antimicrobial chemotherapy (P-SACT) to inhibit the biofilms of periopathogens bacteria on surfaces of the titanium dental implants.

Materials And Methods: Following synthesis and confirmation of Chitosan Nanoparticles-Indocyanine green (CNPs-ICG) as photo-sonosensitizer, the mature biofilm model of the polymicrobial synergism of periopathogens was formed on the surface of the titanium dental implants. The quantitative and qualitative evaluations of periopathogens biofilms were performed using microbial viability and scanning electron microscopy analysis of the following groups of treatment modalities (n = 5): 1- Control (periopathogens biofilm without treatment), 2- ICG, 3- CNPs-ICG, 4- diode laser, 5- aPDT/ICG, 6- aPDT/CNPs-ICG, 7- ultrasound, 8- SACT/ICG, 9- SACT/CNPs-ICG, 10- PSACT/ICG, 11- PSACT/CNPs-ICG, and 12-0.2% chlorhexidine (CHX).

Results: A significant reduction in the log CFU/mL of periopathogens was observed in the groups treated with aPDT/ICG, aPDT/CNPs-ICG, SACT/ICG, SACT/CNPs-ICG, PSACT/ICG, PSACT/CNPs-ICG, and 0.2% CHX up to 5.3, 6.5, 5.6, 6.6, and 8.8 log, respectively, when compared with control group (P < 0.05). PSACT/CNPs-ICG group demonstrated significantly higher capacity in eliminating the periopathogens biofilm compared with other groups (P < 0.05). However, there was no significant difference between PSACT/CNPs-ICG and 0.2% CHX (P > 0.05). Microscopic images revealed that biofilms treated with PSACT were comprised mainly of deformed and dead cells.

Conclusions: These results highlight the potential of PSACT/CNPs-ICG for the decontamination of the dental implant surfaces from the polymicrobial synergism of periopathogens biofilm.