title: Periodontal tissue reaction to customized nano-hydroxyapatite block scaffold in one-wall intrabony defect: a histologic study in dogs.
abstract: OBJECTIVE
  This study evaluated histologically the tissue responses to and the effects of a customized nano-hydroxyapatite (n-HA) block bone graft on periodontal regeneration in a one-wall periodontal-defect model.
  
  
  METHODS
  A customized block bone for filling in the standardized periodontal defect was fabricated from prefabricated n-HA powders and a polymeric sponge. Bilateral 4×4×5 mm (buccolingual width×mesiodistal width×depth), one-wall, critical-size intrabony periodontal defects were surgically created at the mandibular second and fourth premolars of five Beagle dogs. In each dog, one defect was filled with block-type HA and the other served as a sham-surgery control. The animals were sacrificed following an 8-week healing interval for clinical and histological evaluations.
  
  
  RESULTS
  Although the sites that received an n-HA block showed minimal bone formation, the n-HA block was maintained within the defect with its original hexahedral shape. In addition, only a limited inflammatory reaction was observed at sites that received an n-HA block, which might have been due to the high stability of the customized block bone.
  
  
  CONCLUSIONS
  In the limitation of this study, customized n-HA block could provide a space for periodontal tissue engineering, with minimal inflammation.
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Jung-Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Weon-Yeong
authors.initials: WY
authors.lastname: Park
authors.forename: Jae-Kook
authors.initials: JK
authors.lastname: Cha
authors.forename: Ui-Won
authors.initials: UW
authors.lastname: Jung
authors.forename: Chang-Sung
authors.initials: CS
authors.lastname: Kim
authors.forename: Yong-Keun
authors.initials: YK
authors.lastname: Lee
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Choi