title: Bone regeneration around implants using spherical and granular forms of bioactive glass particles.
abstract: OBJECTIVE
  It has been reported that previous Biogran (3i Implant Innovations, Inc., Palm Beach Gardens, FL) can be converted in vitro into hydroxyapatite (Biogran II) to accelerate new bone formation. The purpose of this study was to evaluate the bone regeneration around implants placed in critical-sized defects in rabbit tibia using granular and spherical forms of Biogran II in regards to implant contact, bone-to-graft contact, bone graft area, and total bone volume.
  
  
  METHODS
  Twelve adult New Zealand rabbits were used, offering 24 surgical sites (1 in each tibia), where 6-mm round defects were created allowing the homocentric insertion of a screw type experimental implant with Osseotite (3i Implant Innovations, Inc.) surface. Half of the defects (group A) were filled up with spherical and half (group B) with granular forms of Biogran II. Ossix (3i Implant Innovations, Inc.) membranes covered the surgical sites.
  
  
  RESULTS
  The histological evaluation after 8 weeks showed new bone formation in both groups, without any statistically significant differences in regards to bone-to-implant contact, bone-to-graft contact, bone graft area, and bone volume. Both dissolution of the outer shell and inner silica gel of the particles were observed mostly in spherical particles. In addition, new bone formation within the protected pouch interconnected with the surrounding new bone was observed exclusively in spherical particles of Biogran II.
  
  
  CONCLUSIONS
  Faster dissolution of both outer and inner portions of spherical particles of Biogran II led to better integration with the surrounding new bone during an 8-week period of healing.
authors.affiliation: Department of Alveolar Surgery, Implantology and Radiology, Dental School of the Aristotle University of Thessaloniki, Thessaloniki, Greece. veis@otenet.gr
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Veis
authors.forename: Nikolaos N
authors.initials: NN
authors.lastname: Dabarakis
authors.forename: Nikolaos A
authors.initials: NA
authors.lastname: Parisis
authors.forename: Anastasios T
authors.initials: AT
authors.lastname: Tsirlis
authors.forename: Theodora G
authors.initials: TG
authors.lastname: Karanikola
authors.forename: Dimitra V
authors.initials: DV
authors.lastname: Printza
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use*; D001847:Bone Diseases / Q000473:pathology / Q000601:surgery; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000627:therapeutic use*; D015921:Dental Implants; D005898:Glass; D008567:Membranes, Artificial; D016348:Osseointegration / Q000502:physiology; D011817:Rabbits; D012995:Solubility; D013499:Surface Properties; D013977:Tibia / Q000473:pathology / Q000601:surgery; D014945:Wound Healing / Q000502:physiology
chemical_list: D001672:Biocompatible Materials; C073544:Biogran; D018786:Bone Substitutes; D015921:Dental Implants; D008567:Membranes, Artificial