Factors affecting the antibacterial effects of Nd : YAG laser in vivo

Abstract

Background and Objectives: One of the main advantages of laser surgery is it's bactericidal effect which reduces the risk of postoperative infections. Several study designs have been set to investigate this effect. Aim of this study was to research if the bactericidal effect of laser tool was affected from several factors in vitro studies. Study Design/Materials and Methods: To determinate and investigate the bactericidal effect of laser in an original model, alpha-hemolytic streptococcus, Bacterioides fragilis, Neisseria, Streptococcus salivarius, Staphylococcus aureus, and Candida albicans were prepared in 10(4), 10(6) and 10(8) inoculum and placed in Mueller-Hinton Broth which have five different proportions of sheep blood. Samples which exposed with various energy levels of Nd:YAG laser were spread on agar plates, and at the end of an incubation time the colonization counted comparatively. The lowest energy level without colonization was accepted as minimal bactericidal energy level. Results: Highest minimum bactericidal energy level is used for alpha-hemolytic streptococcus and lowest values for neisseria. Bactericidal effect decreased on suspensions, of which population of microorganisms are high and hemoglobin concentration was high in the broth. Conclusions: These findings suggest that the Nd:YAG laser has a higher bactericidal effect when sheep blood is added to the media. Factors like population and type of bacteria in the irradiated suspension affect minimum bactericidal energy level. (C) 2003 Wiley-Liss, Inc.