Periimplantitis and epithelial downgrowth are two of the main conditions related to dental implants failure. In transmucosal implants, bacterial infection is due to bacterial penetration through the soft tissues in contact with the implant and biofilm formation on the implant surface. The defect in soft tissue sealing and the apically epithelial downgrowth till to the bone level are responsible of bone resorption and implant mobilization promoted by inflammation of the connective tissue. Gingival fibroblasts play an important role in periimplantitis because they are the promoters of the inflammatory process. Moreover, the related inflammatory state is commonly driven also to counteract bacteria implants colonization. In the present work, a new technology for soft tissue contact is proposed. The first focus of this research was to promote and drive gingival fibroblasts adhesion, proliferation and orientation on commercially pure titanium surfaces by means of mechanically produced nanogrooves (0.1-0.2 ?m) and keratin nanofibers deposited by electrospinning. The prepared surfaces have been characterized for their morphology (FESEM), chemical composition (FTIR, XPS), surface charge (zeta potential) and wettability (contact angle). Afterwards, their performances in terms of cells (human primary gingival fibroblasts) adhesion were compared to mirror-like polished titanium surfaces. Results revealed that gingival fibroblasts viability was not negatively affected by the applied surface roughness or by keratin nanofibers. On the opposite, cells adhesion and spread were strongly influenced by surface roughness revealing a significant cell orientation along the produced nanogrooves. However, the keratin influence was clearly predominant with respect to surface topography. The second aim of this research was to introduce antibacterial properties to the developed technology. So, mirror-polished keratin-coated surfaces were doped with silver (Ag) using different concentrations of silver nitrate as a precursor. The antibacterial properties of the Ag-doped specimens were tested against a multidrug-resistant Staphylococcus aureus biofilm through morphology (FESEM) and metabolic assay (XTT); reduction in viability was significant (480% reduction within 72 h). Lastly, the cytocompatibility of the specimens was confirmed using human primary gingival fibroblasts, whose viability, spread and matrix deposition were found to be comparable to those of untreated Ti polished controls. Thus, Ag surface enrichment was effective in reducing viability and maturation of S. aureus biofilm, without compromising human cell viability. The strategy thus appears to be very promising to introduce surface features in line with the main requirements for transmucosal dental implants.
Antibacterial keratin nanofibers on titanium surfaces for fibroblast adhesion and prevention of biofilm formation
Francesca Truffa Giachet;Claudia Vineis;Alessio Varesano;Vincenzo Guarino
2018
Abstract
Periimplantitis and epithelial downgrowth are two of the main conditions related to dental implants failure. In transmucosal implants, bacterial infection is due to bacterial penetration through the soft tissues in contact with the implant and biofilm formation on the implant surface. The defect in soft tissue sealing and the apically epithelial downgrowth till to the bone level are responsible of bone resorption and implant mobilization promoted by inflammation of the connective tissue. Gingival fibroblasts play an important role in periimplantitis because they are the promoters of the inflammatory process. Moreover, the related inflammatory state is commonly driven also to counteract bacteria implants colonization. In the present work, a new technology for soft tissue contact is proposed. The first focus of this research was to promote and drive gingival fibroblasts adhesion, proliferation and orientation on commercially pure titanium surfaces by means of mechanically produced nanogrooves (0.1-0.2 ?m) and keratin nanofibers deposited by electrospinning. The prepared surfaces have been characterized for their morphology (FESEM), chemical composition (FTIR, XPS), surface charge (zeta potential) and wettability (contact angle). Afterwards, their performances in terms of cells (human primary gingival fibroblasts) adhesion were compared to mirror-like polished titanium surfaces. Results revealed that gingival fibroblasts viability was not negatively affected by the applied surface roughness or by keratin nanofibers. On the opposite, cells adhesion and spread were strongly influenced by surface roughness revealing a significant cell orientation along the produced nanogrooves. However, the keratin influence was clearly predominant with respect to surface topography. The second aim of this research was to introduce antibacterial properties to the developed technology. So, mirror-polished keratin-coated surfaces were doped with silver (Ag) using different concentrations of silver nitrate as a precursor. The antibacterial properties of the Ag-doped specimens were tested against a multidrug-resistant Staphylococcus aureus biofilm through morphology (FESEM) and metabolic assay (XTT); reduction in viability was significant (480% reduction within 72 h). Lastly, the cytocompatibility of the specimens was confirmed using human primary gingival fibroblasts, whose viability, spread and matrix deposition were found to be comparable to those of untreated Ti polished controls. Thus, Ag surface enrichment was effective in reducing viability and maturation of S. aureus biofilm, without compromising human cell viability. The strategy thus appears to be very promising to introduce surface features in line with the main requirements for transmucosal dental implants.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
