title: Bone regeneration effects of human allogenous bone substitutes: a preliminary study.
abstract: OBJECTIVE
  The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits.
  
  
  METHODS
  Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation.
  
  
  RESULTS
  In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups.
  
  
  CONCLUSIONS
  Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.
authors.affiliation: Department of Periodontology and Dental Research Institute, Seoul National University College of Dentistry, Seoul, Korea.
authors.forename: Deok-Won
authors.initials: DW
authors.lastname: Lee
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Koo
authors.forename: Yang-Jo
authors.initials: YJ
authors.lastname: Seol
authors.forename: Yong-Moo
authors.initials: YM
authors.lastname: Lee
authors.forename: Young
authors.initials: Y
authors.lastname: Ku
authors.forename: In-Chul
authors.initials: IC
authors.lastname: Rhyu
authors.forename: Chong-Pyoung
authors.initials: CP
authors.lastname: Chung
authors.forename: Tae-Il
authors.initials: TI
authors.lastname: Kim