title: Bone tissue response to porous and functionalized titanium and silica based coatings.
abstract: BACKGROUND
  Topography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings.
  
  
  METHODS
  Six-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO(2)); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 µm, BAF-500), in the implant vicinity (100 µm, BAF-100) and further away (100-500 µm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis.
  
  
  RESULTS
  After 2 weeks, the differences in BAF-500 for different surfaces were not significant (p>0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-µm compared to the 400-µm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR.
  
  
  CONCLUSIONS
  BAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn't stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn't stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation.
authors.affiliation: Department of Prosthetic Dentistry, BIOMAT Research Group, K. U. Leuven, Leuven, Belgium.
authors.forename: Amol
authors.initials: A
authors.lastname: Chaudhari
authors.forename: Annabel
authors.initials: A
authors.lastname: Braem
authors.forename: Jozef
authors.initials: J
authors.lastname: Vleugels
authors.forename: Johan A
authors.initials: JA
authors.lastname: Martens
authors.forename: Ignace
authors.initials: I
authors.lastname: Naert
authors.forename: Marcio Vivan
authors.initials: MV
authors.lastname: Cardoso
authors.forename: Joke
authors.initials: J
authors.lastname: Duyck
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D020007:Implants, Experimental; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D016348:Osseointegration; D016062:Porosity; D019736:Prostheses and Implants; D011817:Rabbits; D012822:Silicon Dioxide / Q000737:chemistry*; D013977:Tibia / Q000473:pathology; D014025:Titanium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium