title: [Inhibition effect of methylene blue on the acids production of Streptococcus mutans].
abstract: OBJECTIVE
  To study the effect of methylene blue on the growth and acid production of Streptococcus mutans, and the effect of methylene blue on acid production metabolism in plaque glycolysis model (i-PGM) in vitro, and investigate the practicability of methylene blue as a new kind of dental caries prevention agent.
  
  
  METHODS
  Nephelometer method was used to measure OD value of Streptococcus mutans culture fluid in the different incubation conditions. The kinds and quantities of acid produced by Streptococcus mutans in the different incubation conditions were measured with gas chromatography. pH values of glycolysis buffer media of i-PGM in the different treatment conditions were measured by ORION electrode.
  
  
  RESULTS
  (1) The OD value of Streptococcus mutans treated by methylene blue was lower than that by normal saline, and there was significant statistical difference between them. (2) The kinds of acid in three different culture fluid were same, but the total quantities of acid were significantly different among three different culture fluid, in which the total quantities of acid of culture fluids treated by glucose was the greatest, and treated by methylene blue was the lest. (3) The pH value of i-PGM treated by methylene blue was significantly different compared with negative control group, but was not significantly different compared with positive control group.
  
  
  CONCLUSIONS
  Methylene blue can inhibit the growth and acid production metabolism of Streptococcus matans and acid production metabolism of i-PGM.
authors.affiliation: Dept. of Stomatology, General Hospital of PLA , Beijing 100853, China.
authors.forename: Cheng-long
authors.initials: CL
authors.lastname: Wang
authors.forename: Hong-chen
authors.initials: HC
authors.lastname: Liu
authors.forename: Zhen-gang
authors.initials: ZG
authors.lastname: Li
authors.forename: Shi-jie
authors.initials: SJ
authors.lastname: Shen
authors.forename: Bing-feng
authors.initials: BF
authors.lastname: Chu
authors.forename: Min
authors.initials: M
authors.lastname: Zhao
authors.forename: Li-zi
authors.initials: LZ
authors.lastname: Huang
mesh_terms: D003731:Dental Caries; D003773:Dental Plaque; D006019:Glycolysis; D008751:Methylene Blue; D013295:Streptococcus mutans
chemical_list: D008751:Methylene Blue