Enhancement of Erythrosine Photodynamic Therapy against Streptococcus mutans by Chlorhexidine

Park, Jongcheol; Park, Howon; Lee, Siyoung

J Korean Acad Pediatr Dent. 2013;40(4): 241-246.

Jongcheol Park¹, Howon Park¹, Siyoung Lee²

¹Department of Pediatric Dentistry, College of Dentistry, Gangneung-Wonju National University
²Department of Microbiology and Immunology, Oral Science Research Center, College of Dentistry, Gangneung-Wonju National University

Corresponding Author: Howon Park ,Tel: +82-33-640-2464, Fax: +82-33-640-3113, Email: pedo@gwnu.ac.kr

Received: April 12, 2013; Accepted: September 7, 2013.

ABSTRACT

The purpose of this study was to investigate the synergistic effects of erythrosine sensitized with a conventional halogen curing unit and sub-minimal bactericidal concentration(sub-MBC) of chorhexidine on bacterial viability of Streptococcus mutans in planktonic state. Sub-minimal bactericidal concentration of chlorhexidine was added into wells containing bacteria and erythrosine. The range of concentrations tested for chorhexidine was from 0.0000001% to 0.001%. The irradiation of the bacterial suspensions was performed for 15 sec with a conventional halogen curing unit light. In another set of experiment, the effects of 0.001% chlorhexidine were observed by adding chlorhexidine into wells containing the sub-minimal bactericidal concentration of erythrosine. At the concetration of 0.001% chlorhexidine, there were no antibacterial effects in the absence of erythrosine PDT(p < 0.05). At the concentraton of 1 μM erythrosine, there was no photodynamic therapy effect in the absence of chlorhexidine(p < 0.05). But in the presence of sub-minimal bactericidal concentration of erythrosine with light exposure, the addition of 0.001% chlorhexidine increased the bactericidal rate(p < 0.05). A combination of erythrosine PDT with sub-MBC chlorhexidine resulted in a significant reduction in bacterial counts when compared to the case with the absence of chlorhexidine.

Keywords: Photodynamic therapy | Erythrosine | Halogen | Streptococcus mutans | Chlorhexidine