title: Micro-CT observation of angiogenesis in bone regeneration.
abstract: OBJECTIVE
  Restoration of an adequate blood supply is essential for the bone healing process and is key to the success of bone augmentation procedures. In this study, we evaluated angiogenesis in rat calvarial flat bone defects using in vivo microfocus computed tomography (micro-CT).
  
  
  METHODS
  Twenty rats were used. The calvarium was exposed and calvarial bone defects of critical (5-mm diameter) and non-critical (2.7-mm diameter) sizes were prepared. Bone regeneration and angiogenesis were evaluated by image analysis using micro-CT and histological examination.
  
  
  RESULTS
  Critical- and non-critical-sized calvarial bone defects showed bone regeneration and angiogenesis around the midsagittal suture. Critical-sized calvarial bone defects showed approximately 1.2% reossification of the original surgical defect, whereas the non-critical-sized defects showed approximately 43.3% reossification at day 28. Furthermore, angiogenesis was observed later in the critical-sized calvarial bone defects (about 38.2%), whereas angiogenesis was observed early in the non-critical-sized calvarial bone defects (about 75.5%) at day 28. New blood vessel networks were observed around defects of both sizes.
  
  
  CONCLUSIONS
  Angiogenesis preceded bone regeneration around critical- and non-critical-sized calvarial bone defects. Angiogenesis led to full bone formation in non-critical-sized defects.
authors.affiliation: Division of Applied Oral Sciences, Nihon University Graduate School of Dentistry, Tokyo, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Udagawa
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sato
authors.forename: Akira
authors.initials: A
authors.lastname: Hasuike
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kishida
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Arai
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
mesh_terms: D000792:Angiography / Q000379:methods; D000818:Animals; D001847:Bone Diseases / Q000473:pathology / Q000503:physiopathology; D001861:Bone Regeneration / Q000502:physiology*; D003238:Connective Tissue / Q000098:blood supply / Q000473:pathology; D003393:Cranial Sutures / Q000098:blood supply / Q000502:physiology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D010294:Parietal Bone / Q000098:blood supply* / Q000503:physiopathology / Q000601:surgery; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D055114:X-Ray Microtomography / Q000379:methods*