title: Streptococcus mutans and Streptococcus sobrinus biofilm formation and metabolic activity on dental materials.
abstract: OBJECTIVE
  To examine potential correlations between streptococcal biofilm formation and lactate production in streptococcal biofilms formed on the surface of dental materials with different surface characteristics.
  
  
  METHODS
  Samples of a glass-ionomer cement (Ketac Molar) and a ceramic (Empress 2) were incubated with whole saliva and suspensions of Streptococcus mutans ATCC 25175 or Streptococcus sobrinus ATCC 33478 for initiating single-species biofilm formation for either 4 or 24 h. The relative amount of adherent, viable cells was determined using a Resazurin and a MTT assay. Metabolic activity was assessed by quantifying lactate production with a modification of the commercial Clinpro Cario L-Pop kit.
  
  
  RESULTS
  Both assays identified similar S. sobrinus biofilm formation on the two substrata; for S. mutans, the MTT test showed significantly fewer streptococci on the glass-ionomer cement than on the ceramic. Concerning metabolic activity, for S. sobrinus, significantly higher lactate production was observed for biofilms formed on the glass-ionomer cement in comparison to the ceramic, whereas similar values were identified for S. mutans.
  
  
  CONCLUSIONS
  Within the limitations of the study, the results suggest that the pure amount of adherent streptococci does not a priori indicate the metabolic activity of the cariogenic bacteria organized in the respective biofilm. Thus, comparisons between the relative amount of adherent streptococci and their metabolic activity may allow for an improved understanding of the effect of dental material surfaces on the formation and metabolic activity of streptococcal biofilms.
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany. sebastian.hahnel@klinik.uni-regensburg.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahnel
authors.forename: Gudrun
authors.initials: G
authors.lastname: Mühlbauer
authors.forename: Judith
authors.initials: J
authors.lastname: Hoffmann
authors.forename: Andrei
authors.initials: A
authors.lastname: Ionescu
authors.forename: Ralf
authors.initials: R
authors.lastname: Bürgers
authors.forename: Martin
authors.initials: M
authors.lastname: Rosentritt
authors.forename: Gerhard
authors.initials: G
authors.lastname: Handel
authors.forename: Ingo
authors.initials: I
authors.lastname: Häberlein
mesh_terms: D000704:Analysis of Variance; D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D015169:Colony Count, Microbial; D003776:Dental Porcelain; D005260:Female; D005899:Glass Ionomer Cements / Q000378:metabolism; D006019:Glycolysis; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D018020:Lithium Compounds / Q000378:metabolism; D012463:Saliva / Q000382:microbiology; D018709:Statistics, Nonparametric; D013295:Streptococcus mutans / Q000378:metabolism*; D016986:Streptococcus sobrinus / Q000378:metabolism*; D013499:Surface Properties; D055815:Young Adult
chemical_list: C118557:Empress 2; D005899:Glass Ionomer Cements; D018020:Lithium Compounds; C110712:ketac-molar; D003776:Dental Porcelain; D019344:Lactic Acid