Susceptibility of Dental Caries Microcosm Biofilms to Photodynamic Therapy Mediated by Fotoenticine

Abstract

Photodynamic therapy (PDT) mediated by Fotoenticine® (FTC), a new photosensitizer derived from chlorin e-6, has shown in vitro inhibitory activity against the cariogenic bacterium Streptococcus mutans. However, its antimicrobial effects must be investigated on biofilm models that represent the microbial complexity of caries. Thus, we evaluated the efficacy of FTC-mediated PDT on microcosm biofilms of dental caries. Decayed dentin samples were collected from different patients to form in vitro biofilms. Biofilms were treated with FTC associated with LED irradiation and analyzed by counting the colony forming units (log10 CFU) in selective and non-selective culture media. Furthermore, the biofilm structure and acid production by microorganisms were analyzed using microscopic and spectrophotometric analysis, respectively. The biofilms from different patients showed variations in microbial composition, being formed by streptococci, lactobacilli and yeasts. Altogether, PDT decreased up to 3.7 log10 CFU of total microorganisms, 2.8 log10 CFU of streptococci, 3.2 log10 CFU of lactobacilli and 3.2 log10 CFU of yeasts, and reached eradication of mutans streptococci. PDT was also capable of disaggregating the biofilms and reducing acid concentration in 1.1 to 1.9 mmol lactate/L. It was concluded that FTC was effective in PDT against the heterogeneous biofilms of dental caries.

Smart dental materials for antimicrobial applications

“…A summary of the more common PS utilized to eradicate dental pathogens is presented in Table 3 . The antimicrobial effects of aPDT with Fotoenticine® are greater than methylene blue in the control of S. mutans [ 230 ]. Recently, Fotoenticine® and toluidine blue O were effective against the heterogeneous (multispecies) biofilms of dental caries [ 230 , 231 ].…”

“…The antimicrobial effects of aPDT with Fotoenticine® are greater than methylene blue in the control of S. mutans [ 230 ]. Recently, Fotoenticine® and toluidine blue O were effective against the heterogeneous (multispecies) biofilms of dental caries [ 230 , 231 ]. Toluidine blue has also been successfully evaluated against E. faecalis for disinfection of root canals [ 232 , 233 ].…”

Photonics-based treatments: Mechanisms and applications in oral infectious diseases

“…Antimicrobial photodynamic therapy can effectively inhibit the growth of a variety of microorganisms associated with cariogenic biofilms, including Streptococcus, Streptococcus mutans (S. mutans), Lactobacillus, and yeast (Garcia et al, 2021). A nanoplatform composed of assembling toluidine blue O (TBO) and superparamagnetic iron oxide nanoparticles (MagTBO) was designed to achieve enhanced antimicrobial activity (Balhaddad et al, 2021).…”

Strategies for dispersion of cariogenic biofilms: applications and mechanisms

“…Due to the high carbohydrate content, the S. mutans biofilms exhibited greater absorption to PS than fungal cells, which might be the reason for the susceptibility of S. mutans ( Sharma et al, 2011 ). Even in a complex polymicrobial biofilm, S. mutans are more susceptible to FTC-mediated photodynamic therapy ( Garcia et al, 2021 ).…”

“…Due to the high carbohydrate content, the S. mutans biofilms exhibited greater absorption to PS than fungal cells, which might be the reason for the susceptibility of S. mutans (Sharma et al, 2011). Even in a complex polymicrobial biofilm, S. mutans are more susceptible to FTC-mediated photodynamic therapy (Garcia et al, 2021). H 2 O 2 and nanoparticles with the peroxidase-like activity present an ideal antibiofilm strategy by generating free radicals for the elimination of oral biofilms.…”