Jaber Ghorbani - Department of Microbiology, School of medicine, Tehran university of medical science, Tehran, Iran

Background and Aim:Increasing the resistance of oral pathogens such as Streptococcus mutans to antibiotics has prompted the incentive to use alternative methods including photodynamic therapy. However, few studies have attempted to develop the antimicrobial activity of a novel, natural-derived photosensitizer. The aim of this study was to investigate the in-vitro photochemical effects of echium amoenum extract against Streptococcus mutans suspension and its comparison with chlorhexidine di-gluconate (CHX).Methods:In this experimental study, suspension of Streptococcus mutans was treated in four separate groups: 1) echium amoenum extract (50 μM) 2) CHX (2%) 3) echium amoenum extract (50 μM) + light irradiation using diode laser with a wavelength of 450 nm 4) diode laser radiation; using micro broth dilution test. Data were analyzed by one way ANOVA and Tukey HSD tests (p<0.05).Results:Regarding the Minimum Inhibitory Concentration (MIC), echium amoenum Extract showed a significant decrease of MIC in the presence of laser light compared with the absence of laser light. The minimum inhibitory concentration of CHX was significantly lower than that of the echium amoenum extract.Conclusion:These preliminary in vitro findings imply that echium amoenum derivatives can be studied in more investigations as a novel photosensitizer.

Photodynamic therapy, Streptococcus mutans, antimicrobial Photodynamic therapy, photosensitizer