title: Tomographic and histometric analysis of autogenous bone block and synthetic hydroxyapatite block grafts without rigid fixation on rabbit calvaria.
abstract: OBJECTIVE
  The preferred material for bone augmentation beyond the envelope of skeletal bone is the bone block graft, due to its dimensional stability. We evaluated the necessity of rigid fixation for the bone block graft, and compared the bone regeneration and volume maintenance associated with grafting using a synthetic hydroxyapatite block (HAB) and an autogenous bone block (ABB) without rigid fixation on rabbit calvaria over two different periods.
  
  
  METHODS
  Cylinder-shaped synthetic HAB and ABB were positioned without fixation on the rabbit calvarium (n=16). The animals were sacrificed at 4 or 8 weeks postoperatively, and the grafted materials were analyzed at each healing period using microcomputed tomography and histologic evaluation.
  
  
  RESULTS
  Integration of the graft and the recipient bed was observed in all specimens, although minor dislocation of the graft materials from the original position was evident in some specimens (six ABB and ten HAB samples). A tendency toward progressive bone resorption was observed in the grafted ABB but not in the grafted HAB, which maintained an intact appearance. In the HAB group, the area of new bone increased between 4 and 8 weeks postoperatively, but the difference was not statistically significant.
  
  
  CONCLUSIONS
  The nonfixed HAB was successfully integrated into the recipient bed after both healing periods in the rabbit calvaria. In spite of limited bone formation activity in comparison to ABB, HAB may be a favorable substitute osteoconductive bone material.
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Soo-Yong
authors.identifier: 0000-0002-9988-1084
authors.initials: SY
authors.lastname: Bae
authors.affiliation: Department of Periodontology, Dankook University College of Dentistry, Cheonan, Korea.
authors.forename: Jung-Chul
authors.identifier: 0000-0002-2041-8047
authors.initials: JC
authors.lastname: Park
authors.affiliation: Department of Periodontology, Dankook University College of Dentistry, Cheonan, Korea.
authors.forename: Hyun-Seung
authors.identifier: 0000-0002-1410-9731
authors.initials: HS
authors.lastname: Shin
authors.affiliation: Research Center for Oral Disease Regulation of the Aged, Chosun University School of Dentistry, Gwangju, Korea.
authors.forename: Yong-Keun
authors.identifier: 0000-0003-3228-7109
authors.initials: YK
authors.lastname: Lee
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Seong-Ho
authors.identifier: 0000-0001-6704-6124
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Ui-Won
authors.identifier: 0000-0001-6371-4172
authors.initials: UW
authors.lastname: Jung
keywords: Animal experiments; Bone regeneration; Hydroxyapatites