title: Effect of direct current on surface structure and cytocompatibility of titanium dental implants.
abstract: OBJECTIVE
  A low direct current can be used to disinfect dental titanium implants in simulated physiologic environments. The aim of this study was to determine whether this treatment affects implant surface structure and cytocompatibility.
  
  
  METHODS
  Titanium test disks with a sandblasted, acid-etched, large-grit (SLA) surface were placed as anodes in an electrolytic bath with physiologic saline and treated with 15 mA of current for 15 minutes. Surfaces were analyzed by light and electron microscopy and contact angle measurement. Depth profile analyses of SLA disks were run at subsurface levels from 0 to 1,000 nm. The proliferation and viability of preosteoblastic cells and human foreskin fibroblasts on implant surfaces were assessed. Alkaline phosphatase (ALP) activity was determined with and without exposure to bone morphogenetic protein-2 (BMP-2). Mineralization was determined after 4 weeks.
  
  
  RESULTS
  A blue discoloration was observed after treating the SLA disks, but no damage was recognized microscopically. An oxidation layer formed on the surface and the wettability of the disks increased significantly. Cell proliferation and initial maturation were not affected by the treatment. Mineralization and ALP activity of BMP-exposed cells, however, were slightly but significantly reduced on test disks.
  
  
  CONCLUSIONS
  The current study showed that the alterations in implant color after electrochemical treatment did not reflect significant surface changes, which would preclude cell adhesion and growth or have a major impact on osteoblastic differentiation or maturation.
authors.forename: Philipp
authors.initials: P
authors.lastname: Sahrmann
authors.forename: Dirk
authors.initials: D
authors.lastname: Mohn
authors.forename: Matthias
authors.initials: M
authors.lastname: Zehnder
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
authors.forename: Thomas
authors.initials: T
authors.lastname: Imfeld
authors.forename: Franz E
authors.initials: FE
authors.lastname: Weber
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology; D002448:Cell Adhesion; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D015921:Dental Implants; D004203:Disinfection / Q000379:methods*; D004560:Electricity; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013499:Surface Properties; D014025:Titanium; D017155:Wettability
chemical_list: D055396:Bone Morphogenetic Protein 2; D015921:Dental Implants; D014025:Titanium; D000469:Alkaline Phosphatase