title: Surface modification and its effect on attachment, spreading, and proliferation of human gingival fibroblasts.
abstract: OBJECTIVE
  The purpose of this study was to exploit potential methods of surface modification for improving the seal between the neck portion of a dental implant and the surrounding soft tissue.
  
  
  METHODS
  Titanium surfaces were modified by machining (SM-Ti group); machining and acid etching (AE-Ti group); or machining, acid etching, and depositing 4.5 collagen/hyaluronic acid (col/HA) polyelectrolyte bilayers (CHC-Ti group). These were analyzed using scanning electron microscopy, scanning force microscopy, x-ray photoelectron spectroscopy, contact angle measurement, and quartz crystal microbalance measurement. The degradation behavior of the col/HA multilayer coating was measured. Next, human gingival fibroblasts (HGFs) were cultured on the different surfaces, and cell morphology and spreading were observed using fluorescence microscopy and a shape factor measurement. Cell proliferation was examined by fluorometric quantification of the amount of cellular DNA. Matrix formation of HGFs was determined via enzyme-linked immunosorbent assay. Gene expression was analyzed via reverse transcriptase polymerase chain reaction.
  
  
  RESULTS
  Similar surface topology for these three groups was observable on a microscopic scale, and morphologic differences were apparent on the nanoscale. Both acid etching and col/HA deposition improved the hydrophilicity of the titanium surface, in contrast to machining alone. Each col/HA bilayer was about 5 nm thick. The col/HA coating degraded in about a week. Attachment and spreading of HGFs was better on the CHC-Ti surface than on the SM-Ti or AE-Ti surfaces. Moreover, the proliferation and differentiation of HGFs were greatly stimulated when cultured on CHC-Ti.
  
  
  CONCLUSIONS
  In contrast to two control surfaces (one machined, one machined and acid-etched), col/HA treatment of Ti improved the attachment, spreading, proliferation, and differentiation of HGFs.
authors.affiliation: Department of Oral and Maxillofacial Surgery, the Affiliated Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
authors.forename: Shifang
authors.initials: S
authors.lastname: Zhao
mesh_terms: D000134:Acid Etching, Dental; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000494:pharmacology*; D003722:Dental Alloys / Q000737:chemistry / Q000494:pharmacology*; D015921:Dental Implants; D019232:Dental Restoration Failure; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D020869:Gene Expression Profiling; D005881:Gingiva / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D013499:Surface Properties; D014025:Titanium
chemical_list: D020099:Coated Materials, Biocompatible; D003722:Dental Alloys; D015921:Dental Implants; D014025:Titanium