title: Micro-CT analysis of alveolar bone healing using a rat experimental model of critical-size defects.
abstract: OBJECTIVE
  This study was designed to establish a rat model of a critical size alveolar bone defect.
  
  
  METHODS
  Standardized buccal or mesiobuccal alveolar bone defects were made around the right first mandibular molar of 12-week-old rats, and the left was used as a control. Alveolar bone healing was examined quantitatively by three-dimensional micro-computed tomographic imaging. Bone matrix production of osteoblasts and osteocytes during repair of alveolar bone defects was examined with in situ hybridization for type I collagen.
  
  
  RESULTS
  Buccal defects were repaired significantly and the volume decreased by 88.3% in week 24, whereas mesiobuccal defects were repaired little. Osteoblasts and osteocytes expressed type I collagen in both defects in week 3 but showed little expression by week 6 and thereafter, leaving the mesiobuccal defects largely unrepaired.
  
  
  CONCLUSIONS
  The mesiobuccal defect is a critical-size defect that is not ultimately repaired with bone. It may be an appropriate experimental model for investigating the effectiveness of bone regenerative agents in human alveolar bone loss.
authors.affiliation: Division of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ebina
authors.forename: J
authors.initials: J
authors.lastname: Hatakeyama
authors.forename: M
authors.initials: M
authors.lastname: Onodera
authors.forename: T
authors.initials: T
authors.lastname: Honma
authors.forename: S
authors.initials: S
authors.lastname: Kamakura
authors.forename: H
authors.initials: H
authors.lastname: Shimauchi
authors.forename: Y
authors.initials: Y
authors.lastname: Sasano