title: Late-term healing in an augmented sinus with different ratios of biphasic calcium phosphate: a pilot study using a rabbit sinus model.
abstract: OBJECTIVE
  The aim of this pilot study was to determine the osteoconductivity and dimensional stability of augmented sinuses using different ratios of biphasic calcium phosphate (BCP) in a rabbit sinus model.
  
  
  METHODS
  Each sinus of New Zealand white rabbits (2.5-3.5 kg) was assigned to one of two groups: BCP with a hydroxyapatite to β-tricalcium phosphate (HA:β-TCP) ratio of 70:30 (group TCP30) and BCP with an HA:β-TCP ratio of 30:70 (group TCP70). After preparing a window in the antral wall of a sinus, the Schneiderian membrane was elevated, and the applicable material was grafted. A fluorochrome calcein green was injected five days before euthanizing the animals at four months post-surgery. The specimens were analyzed histologically, histomorphometrically, and by using micro-computed tomography (micro-CT).
  
  
  RESULTS
  Micro-CT analysis revealed that the total augmented volume and the new bone volume did not differ significantly between the two groups whereas the resorption of materials was greater in the TCP70 group. The trabecular thickness, number, and separation also did not differ significantly between the two groups. Histomorphometrically, the areas of total augmentation, new bone, and residual material, as well as the ratio of new-bone-material contact did not differ significantly between the groups. Histologically, the residual particles were more scattered in the TCP70 group than in the TCP30 group. The fluorescence of the calcein green did not differ notably between the two groups.
  
  
  CONCLUSIONS
  The osteoconductivity and dimensional stability of the two BCPs with different ratios tested in this study were comparable after four months of healing. Therefore, we conclude that both BCPs show promise as a bone substitute for sinus augmentation.
authors.affiliation: Department of Periodontology, Kyung Hee University School of Dentistry, Seoul, Korea .
authors.forename: Hyun-Chang
authors.identifier: 0000-0001-7695-1708
authors.initials: HC
authors.lastname: Lim
authors.affiliation: Department of Periodontology, Kyung Hee University School of Dentistry, Seoul, Korea .
authors.forename: Ji-Youn
authors.identifier: 0000-0003-1040-7077
authors.initials: JY
authors.lastname: Hong
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea .
authors.forename: Jung-Seok
authors.identifier: 0000-0003-1276-5978
authors.initials: JS
authors.lastname: Lee
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
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
keywords: Biphasic calcium phosphate; Bone regeneration; Sinus augmentation