title: Three-dimensional analysis of initial biofilm formation on polytetrafluoroethylene in the oral cavity.
abstract: OBJECTIVE
  There is published evidence that polytetrafluoroethylene (PTFE) exhibits beneficial surface characteristics by means of long-term biofilm accumulation. The purpose of this study was to investigate and compare early biofilm formation on polytetrafluoroethylene, ceramic-reinforced polytetrafluoroethylene and as the control group, stainless steel.
  
  
  METHODS
  This study comprised 10 healthy volunteers (5 females and 5 males) with a mean age of 27.3 ± 3.7 years. Three different slabs (two PTFE coatings: one pure and one ceramic-reinforced polytetrafluoroethylene, and stainless steel) were placed in random order on a splint in the mandibular molar region. Intraoral splints were inserted for 48 h. After 48 h, we removed the slabs from the splints and stained the biofilm with a two-color fluorescence assay for bacterial viability (LIVE/DEAD BacLight-Bacterial Viability Kit 7012, Invitrogen, Mount Waverley, Australia). The amount of biofilm accumulation was assessed using confocal laser scanning microscopy (CLSM).
  
  
  RESULTS
  The biofilm surface coverage was 55.8 ± 39.8% on pure PTFE-coated probes, 55.9 ± 35.0% on ceramic-reinforced PTFE-coated probes, and 33.3 ± 37.8% on stainless steel. The differences among the three groups were not significant (p = 0.301). Biofilm depth was 5.6 ± 5.4 μm on pure PTFE-coated probes, 5.2 ± 3.8 μm on ceramic-reinforced PTFE-coated probes, and 2.4 ± 2.9 μm on stainless steel. The Friedman test revealed a significant difference in biofilm depth (p = 0.002). Pairwise comparison of biofilm accumulation yielded a significant difference between pure PTFE and ceramic-reinforced PTFE compared to stainless steel (p = 0.017; p = 0.005).
  
  
  CONCLUSIONS
  Our results indicate that the beneficial surface characteristics of PTFE coatings by reducing long-term biofilm are not a result of inhibiting initial bacterial adhesion.
authors.affiliation: Department of Orthodontics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Fuchslocher Hellemann
authors.forename: S
authors.initials: S
authors.lastname: Grade
authors.forename: W
authors.initials: W
authors.lastname: Heuer
authors.forename: M P
authors.initials: MP
authors.lastname: Dittmer
authors.forename: M
authors.initials: M
authors.lastname: Stiesch
authors.forename: R
authors.initials: R
authors.lastname: Schwestka-Polly
authors.forename: A P
authors.initials: AP
authors.lastname: Demling
mesh_terms: D000328:Adult; D001419:Bacteria / Q000166:cytology* / Q000254:growth & development*; D001422:Bacterial Adhesion / Q000502:physiology; D018441:Biofilms / Q000254:growth & development*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008422:Materials Testing; D018613:Microscopy, Confocal / Q000379:methods; D009055:Mouth / Q000166:cytology / Q000382:microbiology*; D016910:Orthodontic Brackets / Q000382:microbiology*; D011138:Polytetrafluoroethylene; D012016:Reference Values; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D003764:Dental Materials; D011138:Polytetrafluoroethylene