Comparison of antibacterial effect of photodynamic therapy using indocyanine green (Emundo) with 2% metronidazole and 2% chlorhexidine gel on Porphyromonas gingivalis (an in-vitro study).

BACKGROUND: The treatment of periodontal disease focuses on eradication or suppression of the pathogenic microbiota within the periodontal pocket. There are some mechanical and chemical ways, and recently antimicrobial photodynamic therapy to eliminate the bacteria. The aim of this in vitro study was to compare the effects of 2% chlorhexidine gel, 2% metronidazole in Orabase, antimicrobial photodynamic therapy with Emundo solution and Emundo solution on P. gingivalis.

METHODS: The antibacterial activities of 2% CHX gel, 2% Metronidazole in Orabase, Emundo+Laser (an infra-red laser diode of 810nm, 300mW, continuous mode radiation, 30s and energy density of 11.5J/cm2), and Emundo against P. gingivalis was tested in vitro using two different methods; (1) Counting CFU/mL and (2) agar diffusion test (ADT). Data of CFU/mL were analyzed using one way ANOVA and Post hoc Tukey test (p<0.05). Data obtained from ADT test were analyzed using Kruskal-Wallis.

RESULTS: The percentage of colony-forming units reduction was (99.75, 99.98) in Metronidazole, (99.66, 99.85) in CHX, and (96.68, 96.68) in Laser+Emundo (96.68, 96.68) groups after 24 and 48h, respectively. The amount of bacterial reduction in terms of log10 CFU/mL was decreased in the Metronidazole, CHX, Laser+Emundo and, Emundo groups, respectively after 48h (p<0.05). The inhibition zone radius was decreased in CHX, Metronidazole and, Laser+Emundo, respectively (p<0.05).

CONCLUSIONS: It can be concluded that within the limitations of this in-vitro study, although photodynamic therapy with Emundo reduced the amount of P. gingivalis significantly, the use of metronidazole 2% in Orabase performed better in terms of reducing the amount of the bacteria. Also, the antibacterial effect of 2% CHX gel on P. gingivalis was significantly more than photodynamic therapy with Emundo.