Ozone Water Bactericidal and Cleaning Effects on Oral Diseases-related Planktonic and Bacterial Biofilms

: Ozone water has long been known as a bactericidal disinfectant. However, the bactericidal effect of ozone water on bacteria associated with oral diseases has not been thoroughly examined. Further, although oral bacteria reside in biofilms, few studies have explored the effects of ozone water on biofilms. In this study, we aimed to investigate the bactericid al effect of ozone water on bacteria and bacterial biofilms associated with oral diseases. We examined the bactericidal and cleaning effects of ozone water on pathogenic bacteria associated with oral diseases ( Staphylococcus aureus , Pseudomonas aeruginosa , Streptococcus mutans , and Porphyromonas gingivalis ) under planktonic and biofilm growth conditions. When planktonic bacteria were exposed to 5-ppm ozone water, a remarkable antibacterial activity was observed against all of the tested bacterial species. Contrarily, biofilms showed high resistance to ozone water; the bacterial load only slightly de creased even after repeated exposure to ozone water. However, when ozone water was continuously applied at a low flow rate to the biofilms on polystyrene disks, the number of bacteria on the disks was significantly decreased. Our results have shown that the continuous application of ozone water can eliminate oral disease-related bacteria even in biofilms. washed between treatments, bacterial numbers were also affected by the washing effect of water and ozone water treatments. There were no signs of a reduction in viable counts of S. aureus , P. aeruginosa , and S. mutans biofilms even after three treatments with ozone water, as well as with water. P . gingivalis strains showed a slight decrease in CFUs after water and ozone water treatments.