title: The influence of 30-day-old Streptococcus mutans biofilm on the surface of esthetic restorative materials--an in vitro study.
abstract: OBJECTIVE
  To evaluate the effects of Streptococcus mutans biofilm/restorative materials interaction on surface roughness, hardness and morphology of materials tested.
  
  
  METHODS
  Empress 2 (E2), Filtek Supreme (FS), Vitremer (V) and Ketac Molar Easymix (KM) were tested. Twenty-five disks of each material were made and divided into three storage groups: (1) 100% relative humidity (n=5); (2) growth medium (BHI and 1% sucrose) (n=5); (3) S. mutans biofilm-growth medium (n=15). Before storage, hardness measurements were immediately obtained from group 1 specimens. After 30 days of storage, the specimens were cleaned in order to obtain the surface roughness and hardness values, besides morphology analysis by scanning electron microscopy.
  
  
  RESULTS
  The surface roughness and hardness values obtained from E2 and FS specimens did not present statistically significant differences among the groups 1, 2 and 3 and between immediate and 30-day-old specimens of each material. However, group 3 specimens of V and KM showed statistically significant higher surface roughness means than other groups. Group 1 specimens of V and KM also showed higher hardness values than the immediate values. Group 3 specimens of V presented decreased hardness values compared with other groups. The scanning electron micrographs showed an increase in surface degradation from group 1 to group 3 for FS, V and KM.
  
  
  CONCLUSIONS
  Thirty-day-old biofilm promotes a negative effect on the surface morphology of FS, V and KM, on the surface roughness of V and KM and on the hardness of V.
authors.affiliation: Department of Restorative Dentistry, Dental Material Area, Faculty of Dentistry of Piracicaba, State University of Campinas, Postal Code 52, São Paulo, Brazil.
authors.forename: Suzana B P
authors.initials: SB
authors.lastname: Fúcio
authors.forename: Fabíola G
authors.initials: FG
authors.lastname: Carvalho
authors.forename: Lourenço Correr
authors.initials: LC
authors.lastname: Sobrinho
authors.forename: Mário A C
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Regina M
authors.initials: RM
authors.lastname: Puppin-Rontani
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003773:Dental Plaque / Q000382:microbiology / Q000517:prevention & control*; D003793:Dental Restoration, Permanent; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D018020:Lithium Compounds / Q000737:chemistry; D013295:Streptococcus mutans / Q000254:growth & development*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C118557:Empress 2; C474035:Filtek Supreme; D005899:Glass Ionomer Cements; C515713:Ketac Molar Easymix; D018020:Lithium Compounds; C084550:Vitremer