title: Corrosion behaviour of titanium in the presence of Streptococcus mutans.
abstract: OBJECTIVE
  The main aim of this in vitro study was to evaluate the influence of Streptococcus mutans on the corrosion of titanium.
  
  
  METHODS
  S. mutans biofilms were formed on commercially pure titanium (CP-Ti) square samples (10mm×10mm×1mm) using a culture medium enriched with sucrose. Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements were used to evaluate the corrosion behaviour of CP-Ti in the presence of S. mutans in Fusayama's artificial saliva. The corrosion of biofilm-free CP-Ti samples was also evaluated in artificial saliva. Biofilms biomass was measured by spectrophotometry, using crystal violet staining, after 1, 2 and 7 days.
  
  
  RESULTS
  The OCP values recorded on CP-Ti in the presence of S. mutans (-0.3±0.02V vs. SCE) was lower than those on biofilm-free CP-Ti (-0.1±0.01V vs. SCE) after 2h of immersion in artificial saliva (p<0.05). That reveals a high reactivity of titanium in presence of S. mutans. Impedance spectra revealed the formation of a compact passive film on titanium in artificial saliva or in the presence of a 2 days old S. mutans biofilm even though the corrosion resistance of CP-Ti has decreased in presence of a S. mutans biofilm.
  
  
  CONCLUSIONS
  The presence of bacterial colonies, such as S. mutans, negatively affected the corrosion resistance of the titanium.
authors.affiliation: Centre for Mechanical and Materials Technologies, CT2M, Universidade do Minho, P-4800-058 Guimarães, Portugal. jsouza@dem.uminho.pt
authors.forename: Júlio C M
authors.initials: JC
authors.lastname: Souza
authors.forename: Pierre
authors.initials: P
authors.lastname: Ponthiaux
authors.forename: Mariana
authors.initials: M
authors.lastname: Henriques
authors.forename: Rosário
authors.initials: R
authors.lastname: Oliveira
authors.forename: Wim
authors.initials: W
authors.lastname: Teughels
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Celis
authors.forename: Luís A
authors.initials: LA
authors.lastname: Rocha
mesh_terms: D058491:Bacterial Load; D018441:Biofilms / Q000254:growth & development; D018533:Biomass; D004396:Coloring Agents; D003343:Corrosion; D003470:Culture Media; D003764:Dental Materials / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D005840:Gentian Violet; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D012464:Saliva, Artificial; D013053:Spectrophotometry / Q000379:methods; D013295:Streptococcus mutans / Q000254:growth & development / Q000502:physiology*; D013395:Sucrose; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D003470:Culture Media; D003764:Dental Materials; D012464:Saliva, Artificial; D013395:Sucrose; D014025:Titanium; D005840:Gentian Violet