title: The effect of different collagen modifications for titanium and titanium nitrite surfaces on functions of gingival fibroblasts.
abstract: OBJECTIVE
  Targeted modifications of the bulk implant surfaces using bioactive agents provide a promising tool for improvement of the long-term bony and soft tissue integration of dental implants. In this study, we assessed the cellular responses of primary human gingival fibroblasts (HGF) to different surface modifications of titanium (Ti) and titanium nitride (TiN) alloys with type I collagen or cyclic-RGDfK-peptide in order to define a modification improving long-term implants in dental medicine.
  
  
  METHODS
  Employing Ti and TiN implants, we compared the performance of simple dip coating and anodic immobilization of type I collagen that provided collagen layers of two different thicknesses. HGF were seeded on the different coated implants, and adhesion, proliferation, and gene expression were analyzed.
  
  
  RESULTS
  Although there were no strong differences in initial cell adhesion between the groups at 2 and 4 hours, we found that all surface modifications induced higher proliferation rates as compared to the unmodified controls. Consistently, gene expression levels of cell adhesion markers (focal adhesion kinase (FAK), integrin beta1, and vinculin), cell differentiation markers (FGFR1, TGFb-R1), extracellular protein markers (type I collagen, vimentin), and cytoskeletal protein marker aktinin-1 were consistently higher in all surface modification groups at two different time points of investigation as compared to the unmodified controls.
  
  
  CONCLUSIONS
  Our results indicate that simple dip coating of Ti and TiN with collagen is sufficient to induce in vitro cellular responses that are comparable to those of more reliable coating methods like anodic adsorption, chemical cross-linking, or RGD coating. TiN alloys do not possess any positive or adverse effects on HGF.
  
  
  CONCLUSIONS
  Our results demonstrate a simple, yet effective, method for collagen coating on titanium implants to improve the long term integration and stability of dental implants.
authors.affiliation: Department of Orthopedics and Traumatology, University Medical Centre of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Ritz
authors.affiliation: Department of Orthopedics and Traumatology, University Medical Centre of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Nusselt
authors.affiliation: Biomet Deutschland GmbH, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Sewing
authors.affiliation: Department of Oral, Maxillofacial and Plastic Surgery, University Medical Centre of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Ziebart
authors.affiliation: Georg-Speyer-Haus, Frankfurt, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kaufmann
authors.affiliation: Department of Orthopedics and Traumatology, University Medical Centre of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Baranowski
authors.affiliation: Department of Orthopedics and Traumatology, University Medical Centre of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany.
authors.forename: P M
authors.initials: PM
authors.lastname: Rommens
authors.affiliation: Department of Orthopedics and Traumatology, University Medical Centre of the Johannes Gutenberg University, Langenbeckstr. 1, 55131, Mainz, Germany. hofmann.trauma-surgery@gmx.net.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hofmann
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D024042:Collagen Type I / Q000494:pharmacology*; D015921:Dental Implants; D005347:Fibroblasts / Q000187:drug effects*; D015870:Gene Expression; D005881:Gingiva / Q000166:cytology*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D009573:Nitrites / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D015921:Dental Implants; D009573:Nitrites; D014025:Titanium
keywords: Collagen; Gingival fibroblast; RGD; Surface modification; Titanium; Titanium nitride