title: Enhanced osseointegration of endosseous implants by predictable sustained release properties of strontium.
abstract: Studies have shown that strontium (Sr) incorporated into surfaces may enhance osseointegration. Thus, we suggested that a sustained Sr release from implant surfaces could improve bone healing. This study verifies and further investigates the effect of a novel Ti-Sr-O functionalized implant surface prepared from a magnetron co-sputtering platform with a continuous release of Sr.
  
  
  METHODS
  Four experimental Ti-Sr-O groups, which differed from each other in Sr contents and pre-wash procedures, were tested. Implants were prepared with a Ti-Sr-O coating by means of magnetron co-sputtering and compared to Grade 4 titanium. Composition, morphology and mechanical stability were analyzed; Sr-release data were gained from in vitro washout experiments. In vivo investigations were carried out in a rat model and analyzed histologically regarding bone-to-implant contact and new bone formation 30 days after implantation.
  
  
  RESULTS
  Structural differences were detected between the two basis Ti-Sr-O coatings with 6.7 at.% and 8.9 at.% Sr, respectively. Different release profiles were observed with 8.9 at.% Sr coating exhibiting the highest long-term release of Sr. Median values of new bone formation and bone-to-implant contact was found to be 60.1% and 91.6%, respectively, for the best group compared to 16.6% and 70.6% for the Grade 4 titanium reference. The increase in new bone formation was found to correlate with the amount of Sr released in vitro.
  
  
  CONCLUSIONS
  The results show that sputtered Ti-Sr-O coatings with sustained release of Sr may improve osseointegration, and could thus have impact on practical applications for medical implants.
authors.affiliation: Department for Cranio-, Maxillofacial and Oral Surgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Vincent
authors.initials: V
authors.lastname: Offermanns
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology, Aarhus University, Aarhus, Denmark.
authors.forename: Ole Zoffmann
authors.initials: OZ
authors.lastname: Andersen
authors.affiliation: Department for Cranio-, Maxillofacial and Oral Surgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Falkensammer
authors.affiliation: Tribology Centre, Danish Technological Institute, Aarhus, Denmark.
authors.forename: Inge Hald
authors.initials: IH
authors.lastname: Andersen
authors.affiliation: Tribology Centre, Danish Technological Institute, Aarhus, Denmark.
authors.forename: Klaus Pagh
authors.initials: KP
authors.lastname: Almtoft
authors.affiliation: Tribology Centre, Danish Technological Institute, Aarhus, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Sørensen
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology, Aarhus University, Aarhus, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Sillassen
authors.affiliation: Tribology Centre, Danish Technological Institute, Aarhus, Denmark.
authors.forename: Christian Sloth
authors.initials: CS
authors.lastname: Jeppesen
authors.affiliation: Department for Cranio-, Maxillofacial and Oral Surgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Rasse
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Faculty of Science and Technology, Aarhus University, Aarhus, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Foss
authors.affiliation: Department for Cranio-, Maxillofacial and Oral Surgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Frank
authors.initials: F
authors.lastname: Kloss
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry / Q000493:pharmacokinetics; D000069343:Bone-Implant Interface; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics; D005260:Female; D017102:Fracture Healing / Q000187:drug effects*; D016348:Osseointegration; D051381:Rats; D017208:Rats, Wistar; D013324:Strontium / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D018786:Bone Substitutes; D003692:Delayed-Action Preparations; D013324:Strontium
keywords: implant; in vivo; osseointegration; strontium; sustained release; titanium