Differential susceptibility of cariogenic and commensal oral Streptococcus species to chemically distinct disinfectants including ozone water in vitro.

BACKGROUND: Streptococcus mutans is the primary causative agent of dental caries. Many Streptococcus species present in the oral cavity are thought to increase the risk of infective endocarditis and pneumonia. Conversely, S. sanguinis, S. oralis, S. salivarius, S. gordonii, and S. mitis are streptococci frequently isolated from the oral cavity and are thought to suppress the colonisation of cariogenic bacteria. Recently, mouthwashes have gained attention as a preventive strategy against dental caries. Therefore, we conducted an experiment to verify the caries prevention effect of various disinfectants on not only S. mutans but also other oral resident bacteria by comparing the number of surviving bacteria and the total amount of biofilm.

METHODS: The effectiveness of the disinfectants tested included two commercially available antiseptics with different mechanisms of action, as well as ozone water.

RESULTS: Crystal violet staining indicated that a 30-s exposure to these disinfectants was largely ineffective in removing biofilms. Adenosine triphosphate (ATP) assays revealed that S. mutans exhibited greater resistance to bactericidal action than non-cariogenic bacteria. Among the three disinfectants used in this experiment, ozone water had the lowest ATP value for S. mutans and showed no significant bactericidal effect against non-mutans Streptococci.