title: Bone tissue response to BMP-2 adsorbed on amorphous microporous silica implants.
abstract: OBJECTIVE
  To evaluate bone regeneration potential of bone morphogenetic protein-2 (BMP-2) adsorbed on amorphous microporous silica (AMS).
  
  
  METHODS
  Four implants [titanium as control (CTR); AMS-coated titanium (AMS), BMP-2 adsorbed on titanium (CTR+BMP) and AMS (AMS+BMP)] were implanted randomly in the tibiae of 20 New Zealand white rabbits. Bone specimens with implants were retrieved 2/4 weeks post implantation and analysed histologically and histomorphometrically. Bone fraction was measured in initial bone-free area (bone regeneration area, BRA) and in the area with initial bone-implant contact [bone adaptation area (BAA)] (BF(BRA)  & BF(BAA) ). Bone-implant contact was measured in BRA (BIC(BRA) ). In vitro BMP-2 release profiles were determined to evaluate the impact of the carrier surface. Mixed models were used for statistical analysis.
  
  
  RESULTS
  BMP-2 release profiles were different for CTR+BMP and AMS+BMP. BIC(BRA)  and BF(BRA)  were significantly increased after 4 weeks compared to 2 weeks for AMS, CTR+BMP and AMS+BMP. However, no differences between the implant types were observed within both healing periods. BF(BAA)  for CTR+BMP was smaller than that for CTR and AMS+BMP after 4 weeks. Despite slower BMP-2 release, AMS+BMP did not stimulate bone regeneration. CTR+BMP caused bone resorption at the bone-implant interface.
  
  
  CONCLUSIONS
  BMP-2 functionalized implant surfaces failed to stimulate bone regeneration and osseointegration.
authors.affiliation: Department of Prosthetic Dentistry, BIOMAT Research Group, KU Leuven, Leuven, Belgium.
authors.forename: Amol
authors.initials: A
authors.lastname: Chaudhari
authors.forename: Marcio Vivan
authors.initials: MV
authors.lastname: Cardoso
authors.forename: Johan
authors.initials: J
authors.lastname: Martens
authors.forename: Katleen
authors.initials: K
authors.lastname: Vandamme
authors.forename: Ignace
authors.initials: I
authors.lastname: Naert
authors.forename: Joke
authors.initials: J
authors.lastname: Duyck
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000009:adverse effects / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D001862:Bone Resorption / Q000139:chemically induced; D020099:Coated Materials, Biocompatible; D004337:Drug Carriers; D020007:Implants, Experimental; D016062:Porosity; D011817:Rabbits; D011897:Random Allocation; D012822:Silicon Dioxide; D013499:Surface Properties; D013977:Tibia / Q000601:surgery
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D004337:Drug Carriers; D012822:Silicon Dioxide