title: Influence of bone morphogenetic protein and proportion of hydroxyapatite on new bone formation in biphasic calcium phosphate graft: two pilot studies in animal bony defect model.
abstract: OBJECTIVE
  The purpose of these two pilot studies using animal bony defect models was to evaluate the influence of bone morphogenetic protein (BMP) and proportion of hydroxyapatite (HA)/beta-tricalcium phosphate (β-TCP) in biphasic calcium phosphate (BCP) graft on new bone formation.
  
  
  METHODS
  In this study, four kinds of synthetic osteoconductive bone materials known for bone growth scaffold, OSTEON™II(HA:β-TCP 30:70), OSTEON™III (HA:β-TCP 20:80), OSTEON™II Collagen, and OSTEON™III Collagen, were prepared as BCP graft materials. In pilot study 1, three BCP materials (OSTEON™II, OSTEON™III, and OSTEON™II Collagen) were grafted in rabbit calvarial defects after impregnating in rhBMP-2. OSTEON™II without the rhBMP-2 impregnation was included in the study as the control. The amount of new bone was examined and measured histologically at 2, 4, and 8 weeks. In pilot study 2, four BCP materials (OSTEON™II, OSTEON™III, OSTEON™II Collagen, and OSTEON™III Collagen) were grafted in beagle dog mandibular defects after soaking in the rhBMP-2. The amount of total bone and new bone were measured three-dimensionally using microCT and healing process was examined histologically at 2, 4, and 8 weeks.
  
  
  RESULTS
  In pilot study 1, rhBMP-2 impregnated groups showed more new bone formation than the rhBMP-2 free group. In pilot study 2, increased new bone formation was observed in time-dependent manner after graft of BCP and BCP-collagen (OSTEON™II, OSTEON™III, OSTEON™II Collagen, and OSTEON™III Collagen) impregnated with rhBMP-2. Also, BCP with a higher proportion of HA (30% HA) showed more favorable result in new bone formation and space maintenance, especially at the 8 weeks.
  
  
  CONCLUSIONS
  From the results of the pilot studies, rhBMP-2 played positive roles in new bone formation and BCP could become a scaffold candidate for rhBMP-2 impregnation to induce new bone formation. Moreover, BCP with a higher proportion of HA (30% HA) could be considered more appropriate for rhBMP-2 carrier.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Pil-Young
authors.initials: PY
authors.lastname: Yun
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea; Department of Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea. Electronic address: kyk0505@snubh.org.
authors.forename: Young-Kyun
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
authors.forename: Kyung-In
authors.initials: KI
authors.lastname: Jeong
authors.affiliation: Department of Oral Histology, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Department of Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Ju-Cheol
authors.initials: JC
authors.lastname: Park
authors.affiliation: Division of Prosthodontics, Department of Dentistry, Korea University Medical Center Anam Hospital, Seoul, Republic of Korea.
authors.forename: Yeon-Jo
authors.initials: YJ
authors.lastname: Choi
mesh_terms: D000818:Animals; D001847:Bone Diseases / Q000473:pathology / Q000601:surgery*; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry / Q000627:therapeutic use*; D018786:Bone Substitutes / Q000737:chemistry / Q000627:therapeutic use*; D024042:Collagen Type I / Q000737:chemistry; D004195:Disease Models, Animal; D004285:Dogs; D006882:Hydroxyapatites / Q000737:chemistry / Q000627:therapeutic use*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000473:pathology; D008336:Mandibular Diseases / Q000473:pathology / Q000601:surgery; D010012:Osteogenesis / Q000187:drug effects*; D010865:Pilot Projects; D016062:Porosity; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000627:therapeutic use; D012886:Skull / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry; D020390:Tooth Socket / Q000473:pathology / Q000601:surgery; D016212:Transforming Growth Factor beta / Q000737:chemistry / Q000627:therapeutic use*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D055396:Bone Morphogenetic Protein 2; D018786:Bone Substitutes; D024042:Collagen Type I; D006882:Hydroxyapatites; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C074950:hydroxyapatite-beta tricalcium phosphate; C499469:recombinant human bone morphogenetic protein-2
keywords: Beta-tricalcium phosphate; Biphasic calcium phosphate; Bone morphogenetic protein; Collagen; Hydroxyapatite