title: Effect of strontium-substituted nanohydroxyapatite coating of porous implant surfaces on implant osseointegration in a rabbit model.
abstract: OBJECTIVE
  This study investigated the effects of a strontium-substituted nanohydroxyapatite (Sr-HA) coating, deposited onto porous implant surfaces using an electrochemical process, on implant osseointegration in a rabbit model.
  
  
  METHODS
  The surfaces were analyzed by field-emission scanning electron microscopy, x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), a portable surface roughness tester, and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Thirty implants (half HA-coated and half Sr-HA-coated) were inserted into femurs of 15 rabbits. After 2, 4, and 8 weeks, the femurs were retrieved and prepared for histomorphometric evaluation.
  
  
  RESULTS
  Microscopic examination showed a surface topography of rodlike crystals on both surfaces. XRD and FT-IR showed that the phase of the deposits was HA. No differences were found in surface roughness between the two groups. ICP-AES showed that the Sr/(Ca+Sr) molar ratio of Sr-HA coating was 10.1 mol%. Histologic observation showed that new bone appeared on both surfaces after 2 weeks and became mature after 8 weeks. Histomorphometric analysis showed no differences between the two groups in bone-to-implant contact at 2 weeks or in bone area within all threads at 2 and 4 weeks. The Sr-HA coated group had significantly higher bone-to-implant contact at 4 and 8 weeks. Significant differences were also found in bone area at 8 weeks.
  
  
  CONCLUSIONS
  The present study showed that this Sr-HA coating, deposited using an electrochemical process, has the potential to enhance implant osseointegration.
authors.affiliation: Department of Implantology, Stomatology Hospital, Medical School, Zhejiang University, Hangzhou, China.
authors.forename: Guo-li
authors.initials: GL
authors.lastname: Yang
authors.forename: Li-na
authors.initials: LN
authors.lastname: Song
authors.forename: Qiao-hong
authors.initials: QH
authors.lastname: Jiang
authors.forename: Xiao-xiang
authors.initials: XX
authors.lastname: Wang
authors.forename: Shi-fang
authors.initials: SF
authors.lastname: Zhao
authors.forename: Fu-ming
authors.initials: FM
authors.lastname: He
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D017886:Durapatite / Q000032:analysis; D004595:Electroplating; D005269:Femur / Q000187:drug effects / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D058726:Nanoconjugates / Q000627:therapeutic use*; D016348:Osseointegration / Q000187:drug effects*; D016062:Porosity; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D013324:Strontium / Q000032:analysis / Q000494:pharmacology*; D013499:Surface Properties / Q000187:drug effects
chemical_list: D020099:Coated Materials, Biocompatible; D058726:Nanoconjugates; D017886:Durapatite; D013324:Strontium