title: Photocatalytically induced hydrophilicity influences bone remodelling at longer healing periods: a rabbit study.
abstract: OBJECTIVE
  Previously, we have reported that photocatalytically active hydrophilicity of the anatase titanium dioxide (TiO₂) nanoparticles coated onto commercially pure titanium discs presented significantly improved hydrophilicity after ultraviolet irradiation. As hydrophilicity has shown enhancement of osseointegration, the in vivo responses were of great interest. The aim of this study was to evaluate whether or not the photo-activated hydrophilicity generated at the time of implant placement has an effect on the longer healing periods for osseointegration.
  
  
  METHODS
  Photocatatytically active nanostructured TiO₂ powder (Degussa P-25), which consists of approximately 80% anatase and 20% rutile, was spin-coated onto commercially pure titanium discs and was heat-treated thereafter. These P25-coated discs were irradiated with ultraviolet (UV) light for the test (+UV) group, and non-irradiated discs were prepared for the control (-UV) group. Both groups of discs were placed in the rabbits' tibiae. After 12 weeks of healing period, histological analysis and gene expression analysis using real-time RT-PCR were performed.
  
  
  RESULTS
  From the histological analyses, there were no specific differences between -UV and +UV groups. However, from the gene expression analysis, ALP, RUNX-2 and IL-10 were significantly upregulated for the +UV group compared with the -UV group.
  
  
  CONCLUSIONS
  The biologically enhancing effect to photocatalytically activated surfaces remained even after 12 weeks of healing time in terms of genetic responses.
authors: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors: M
authors: M
authors: Hayashi
authors: R
authors: R
authors: Jimbo
authors: Y
authors: Y
authors: Xue
authors: K
authors: K
authors: Mustafa
authors: M
authors: M
authors: Andersson
authors: A
authors: A
authors: Wennerberg
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D006614:Hindlimb / Q000601:surgery; D053758:Nanoparticles; D016348:Osseointegration / Q000502:physiology*; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays; D014945:Wound Healing / Q000502:physiology*
chemical_list: D015921:Dental Implants; C009495:titanium dioxide; D014025:Titanium
keywords: gene expression; hydrophilicity; osseointegration; photocatalyst