Orientation of gingival fibroblasts and collagen to PTFE nano-fibres

The soft tissue/implant interface between the gingival cuff and the abutment component of an endosseous dental implant may be optimised by improving the gingival fibroblast attachment to the abutment. In vitro studies have demonstrated that gingival fibroblasts orient to polytetrafluoroethylene (PTFE) fibres attached to glass slides using a friction transfer process. This produces parallel fibres with dimension in the nanometre scale. Objectives: 1) To determine the alignment of gingival fibroblasts with PTFE fibres on machined titanium substrates. 2) To determine if the aligned cells synthesise similarly orientated collagen. Methods: 1) Implant titanium cylinders (Friadent GmbH) were used. The circular face of the cylinders had concentric machining grooves (mean Ra=250nm). A band of PTFE fibres were applied across the machining marks, parallel to each other and with dimensions of <50nm in height and 10 to 100nm in width. Human gingival fibroblasts (HGF-1, ATCC) were seeded onto substrates (1000 cells/cm2), incubated under standard conditions, fixed after 1, 4 or 7 days and processed for light or scanning electron microscopy. 2) Glass coverslips were coated and seeded according to the same protocol. The cells were fixed weekly up to 6 weeks, stained with picro-sirius red and viewed using plane polarised light microscopy. Results: HGF-1 cells grown on fibre-coated titanium substrates oriented to the fibre-direction at all time points. On uncoated substrates cells oriented to the machining marks. HGF-1 cells synthesised collagen at all time points. Polarised microscopy demonstrated that the collagen produced by the cells was oriented in the fibre direction. On uncoated substrates the collagen produced by the cells was oriented randomly. Conclusion: HGF-1 cells oriented to PTFE nano-fibres in preference to the machining marks. HGF-1 cells synthesised collagen that also oriented to the fibre direction. The financial support of Friadent GmbH, Medical Devices Faraday Partnership and EPSRC are gratefully acknowledged.