title: In vitro microbiologic evaluation of PTFE and cotton as spacer materials.
abstract: OBJECTIVE
  To microbiologically evaluate the efficacy of cotton and polytetrafluoroethylene (PTFE) tape used as spacer materials.
  
  
  METHODS
  Twenty-six extracted human molars were restored using either cotton or PTFE tape as spacers under a standardized provisional restorative material (Cavit). The teeth were incubated for 7 days in a culture of Streptococcus gordonii or in liquid media alone. The spacers were removed and tested for bacterial contamination. The access cavities were also evaluated for bacterial contamination.
  
  
  RESULTS
  Nine of 10 teeth with cotton spacers and one of 10 teeth with PTFE spacers were positive for S gordonii growth. The nine teeth in the cotton group also showed contamination of the access cavities.
  
  
  CONCLUSIONS
  Even under optimal conditions, cotton spacers may cause leakage into the access cavities. Cotton fibers may serve as a route for bacterial contamination of the access cavities and root canal space. In contrast, PTFE tape did not provide an avenue for bacterial contamination.
authors.affiliation: Department of Endodontics, University of Washington, Seattle, WA, USA. avina@u.washington.edu
authors.forename: Avina
authors.initials: A
authors.lastname: Paranjpe
authors.forename: Sumita
authors.initials: S
authors.lastname: Jain
authors.forename: Karim J
authors.initials: KJ
authors.lastname: Alibhai
authors.forename: Chandur P
authors.initials: CP
authors.lastname: Wadhwani
authors.forename: Richard P
authors.initials: RP
authors.lastname: Darveau
authors.forename: James D
authors.initials: JD
authors.lastname: Johnson
mesh_terms: D032561:Cotton Fiber; D003763:Dental Leakage / Q000382:microbiology*; D006801:Humans; D011138:Polytetrafluoroethylene; D012390:Root Canal Therapy; D054773:Streptococcus gordonii / Q000254:growth & development
chemical_list: D011138:Polytetrafluoroethylene