Three-dimensional analysis of initial biofilm formation on polytetrafluoroethylene in the oral cavity

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.

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).

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).

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.