Objectives: It is known that oral biofilms cause caries, periodontal disease, and systemic diseases. Because of biofilm’s resistant to antibiotics, the problem has been found that as a result of the use of antibiotics, the balance of oral flora is destroyed. Recently, one of the saliva component; arginine is the focus of attention as the approach which changes the human oral microbiome by raising pH. The purpose of this study is to evaluate the effects of arginine by Next Generation Sequencing (NGS) using in situ dental biofilm model which we developed newly.
Methods: The study design was approved by the Ethics Committee in the Osaka University Graduate School of Dentistry (H29-E17). In the arginine and the control group, three healthy volunteers used toothpaste each with and without 8% arginine 2 weeks before sampling. Subsequently, they wore for 8 hours the individual upper jaw appliance in which hydroxyapatite (HA) disks were inserted. After then, 8-hours old biofilms on disks were assessed quantitatively using the culture method, and NGS. And pH measurement was performed from saliva samples of the same time points.
Results: Viable cell counts of control samples were 2.95×10
5 CFU/cm
2 and that of arginine samples were 8.77×10
4 CFU/cm
2. And there was no significant difference of viable cell counts between control and arginine group. PH of saliva in arginine group tended to be higher than that of saliva in control. By microbiome analysis, the bacterial flora showed differently between the two groups. In particular,
Actinomyces JVKM of arginine decreased significantly than that of control (p < 0.05).
Conclusions:
This biofilm model showed that bacterial microbiome had changed using arginine toothpaste by raising the pH in the oral cavity, not changed CFU. This study was supported by a Grant-in-Aid for Scientific Research (#17H04384 and #18K17062) from the Japan Society for the Promotion of Science.