Combinatorial Effects of Arginine and Fluoride on Oral Bacteria

• Published in: Journal of dental research Vol. 94; no. 2; pp. 344 - 353
• Main Authors: Zheng, X., Cheng, X., Wang, L., Qiu, W., Wang, S., Zhou, Y., Li, M., Li, Y., Cheng, L., Li, J., Zhou, X., Xu, X.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01-02-2015; SAGE PUBLICATIONS, INC
• Subjects: Alkalies; Antibiosis - drug effects; Arginine; Arginine - administration & dosage; Arginine - pharmacology; Bacteria; Bacterial Load - drug effects; Biofilms; Biofilms - drug effects; Cariostatic Agents - administration & dosage; Cariostatic Agents - pharmacology; Clinical trials; Dental caries; Dental Caries - microbiology; Dental plaque; Dental Plaque - microbiology; Dentistry; Drug Combinations; Drug Synergism; Enzymes; Fluorescence in situ hybridization; Fluorides; Humans; Hydrogen-Ion Concentration; Materials Testing; Mouth - microbiology; Oral hygiene; Polymerase chain reaction; Polysaccharides, Bacterial - chemistry; Porphyromonas gingivalis - drug effects; Remineralization; Research Reports; Sodium Fluoride - administration & dosage; Sodium Fluoride - pharmacology; Streptococcus - drug effects; Streptococcus infections; Streptococcus mutans - drug effects; Streptococcus sanguis - drug effects; United States > US; Germany; Porphyromonas gingivalis; dental caries; drug synergism; Streptococcus sanguis; biofilms; Streptococcus mutans
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/0022034514561259

Dental caries is closely associated with the microbial disequilibrium between acidogenic/aciduric pathogens and alkali-generating commensal residents within the dental plaque. Fluoride is a widely used anticaries agent, which promotes tooth hard-tissue remineralization and suppresses bacterial activities. Recent clinical trials have shown that oral hygiene products containing both fluoride and arginine possess a greater anticaries effect compared with those containing fluoride alone, indicating synergy between fluoride and arginine in caries management. Here, we hypothesize that arginine may augment the ecological benefit of fluoride by enriching alkali-generating bacteria in the plaque biofilm and thus synergizes with fluoride in controlling dental caries. Specifically, we assessed the combinatory effects of NaF/arginine on planktonic and biofilm cultures of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis with checkerboard microdilution assays. The optimal NaF/arginine combinations were selected, and their combinatory effects on microbial composition were further examined in single-, dual-, and 3-species biofilm using bacterial species–specific fluorescence in situ hybridization and quantitative polymerase chain reaction. We found that arginine synergized with fluoride in suppressing acidogenic S. mutans in both planktonic and biofilm cultures. In addition, the NaF/arginine combination synergistically reduced S. mutans but enriched S. sanguinis within the multispecies biofilms. More importantly, the optimal combination of NaF/arginine maintained a “streptococcal pressure” against the potential growth of oral anaerobe P. gingivalis within the alkalized biofilm. Taken together, we conclude that the combinatory application of fluoride and arginine has a potential synergistic effect in maintaining a healthy oral microbial equilibrium and thus represents a promising ecological approach to caries management.