title: Correlation in the densities of augmented and existing bone in guided bone augmentation.
abstract: OBJECTIVE
  Our previous work used a rabbit experimental model to investigate the effectiveness of guided bone augmentation (GBA). Although a density similar to that of existing bone is required for successful bone augmentation, few studies have compared the densities of augmented and existing bone. The purpose of the present study was to investigate the correlation in the densities of existing and augmented bone following GBA in rabbit calvaria.
  
  
  METHODS
  The calvaria of 18 adult male Japanese white rabbits were exposed. A circular groove and nine small holes were drilled into the cortical surface of each left parietal bone. A customized, standardized, hemispherical titanium cap was press-fitted into each groove. Six animals were sacrificed after each healing period of 1, 3, and 6 months and histomorphometric analyses were conducted.
  
  
  RESULTS
  Significant increases were observed in the area of augmented bone between 1 and 6 months (62.7 ± 21.6% vs. 93.4 ± 3.9%). In contrast, no significant differences among healing periods were observed in the density of augmented or existing bone. Regression analysis demonstrated a significant positive correlation between the densities of augmented and existing bone; the strength of this correlation increased with the length of healing (R(2) =0.97).
  
  
  CONCLUSIONS
  These results suggest that the area of augmented bone increases significantly with the length of healing, filling the occlusive space after 6 months, and that the density of augmented bone depends on that of the existing bone, such that augmented bone has a density about half that of the existing bone.
authors.affiliation: Department of Periodontology, Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan. yamada-y@dent.nihon-u.ac.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamada
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sato
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yagi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ujiie
authors.forename: Sanae
authors.initials: S
authors.lastname: Ezawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
mesh_terms: D000818:Animals; D015519:Bone Density; D001861:Bone Regeneration / Q000502:physiology*; D048091:Guided Tissue Regeneration / Q000379:methods*; D008297:Male; D010294:Parietal Bone / Q000601:surgery*; D019736:Prostheses and Implants; D011817:Rabbits; D012044:Regression Analysis; D014025:Titanium; D014945:Wound Healing
chemical_list: D014025:Titanium