The Efficacy of Photodynamic and Photothermal Therapy on Biofilm Formation of Streptococcus Mutans: An in Vitro Study Publisher Pubmed



Beytollahi L¹ ; Pourhajibagher M² ; Chiniforush N³ ; Ghorbanzadeh R⁴ ; Raoofian R^{5, 6} ; Pourakbari B⁷ ; Bahador A^{1, 2, 3, 8}
Source: Photodiagnosis and Photodynamic Therapy Published:2017

Abstract

Background The alternative antibacterial treatments of photodynamic therapy (PDT) and photothermal therapy (PTT) significantly affect microbiota inactivation. The aim of the present research was the assessment of the antimicrobial and anti-biofilm effects of PDT with toluidine blue O (TBO) and PTT with indocyanine green (ICG) on Streptococcus mutans as a cariogenic bacterium. Materials and methods The S. mutans ATCC 35668 strain was treated with final concentrations of 0.1 mg/mL TBO and 1 mg/mL ICG with energy densities of 17.18 and 15.62 J/cm2, respectively. Cell viability was evaluated after culturing and anti-biofilm potential was analyzed using crystal violet assay and scanning electron microscopy. Results The number of S. mutans colony forming unit (CFU)/mL was significantly lower in the groups submitted to PDT (12.5–100 μg/mL TBO) and PTT (62.5–1000 μg/mL) compared to the control (untreated group). 0.1 mg/mL TBO-PDT and 1 mg/mL ICG-PTT showed stronger inhibitory effects on biofilm formation in S. mutans than other concentration levels, with a reduction of 63.87% and 67.3%, respectively. Conclusion Photo-elimination by high concentrations of TBO-PDT and ICG-PTT exhibited significantly stronger inhibitory effects on biofilm formation and cell viability in S. mutans. © 2016 Elsevier B.V.