title: Combinatorial effects of arginine and fluoride on oral bacteria.
abstract: 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.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: X
authors.initials: X
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: W
authors.initials: W
authors.lastname: Qiu
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: X
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China xin.xu@scu.edu.cn.
authors.forename: X
authors.initials: X
authors.lastname: Xu
mesh_terms: D000468:Alkalies; D000898:Antibiosis / Q000187:drug effects; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003731:Dental Caries / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology; D004338:Drug Combinations; D004357:Drug Synergism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D009055:Mouth / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D016966:Porphyromonas gingivalis / Q000187:drug effects*; D012969:Sodium Fluoride / Q000008:administration & dosage / Q000494:pharmacology*; D013291:Streptococcus / Q000187:drug effects*; D013295:Streptococcus mutans / Q000187:drug effects; D013298:Streptococcus sanguis / Q000187:drug effects
chemical_list: D000468:Alkalies; D002327:Cariostatic Agents; D004338:Drug Combinations; D011135:Polysaccharides, Bacterial; D012969:Sodium Fluoride; D001120:Arginine
keywords: Porphyromonas gingivalis; Streptococcus mutans; Streptococcus sanguis; biofilms; dental caries; drug synergism