title: Four-week histologic evaluation of grafted calvarial defects with adjunctive hyperbaric oxygen therapy in rats.
abstract: OBJECTIVE
  The aim of this study was to characterize the healing in the grafted calvarial defects of rats after adjunctive hyperbaric oxygen therapy.
  
  
  METHODS
  Twenty-eight male Sprague-Dawley rats (body weight, 250-300 g) were randomly divided into two treatment groups: with hyperbaric oxygen therapy (HBO; n=14) and without HBO (NHBO; n=14). Each group was further subdivided according to the bone substitute applied: biphasic calcium phosphate (BCP; n=7) and surface-modified BCP (mBCP; n=7). The mBCP comprised BCP coated with Escherichia-coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) and epigallocatechin-3-gallate (EGCG). Two symmetrical circular defects (6-mm diameter) were created in the right and left parietal bones of each animal. One defect was assigned as a control defect and received no bone substitute, while the other defect was filled with either BCP or mBCP. The animals were allowed to heal for 4 weeks, during which those in the HBO group underwent 5 sessions of HBO. At 4 weeks, the animals were sacrificed, and the defects were harvested for histologic and histomorphometric analysis.
  
  
  RESULTS
  Well-maintained space was found in the grafted groups. Woven bone connected to and away from the defect margin was formed. More angiogenesis was found with HBO and EGCG/BMP-2 (P<0.05). None of the defects achieved complete defect closure. Increased new bone formation with HBO or EGCG/BMP-2 was evident in histologic evaluation, but it did not reach statistical significance in histometric analysis. A synergic effect between HBO and EGCG/BMP-2 was not found.
  
  
  CONCLUSIONS
  Within the limitations of this study, the present findings indicate that adjunctive HBO and EGCG/BMP-2 could be beneficial for new bone formation in rat calvarial defects.
authors: Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea .
authors: Hyeyoon
authors: 0000-0002-3376-4934
authors: H
authors: Chang
authors: Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.; Division of Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea.
authors: Seo-Eun
authors: 0000-0003-3308-3423
authors: SE
authors: Oh
authors: Department of Oral and Maxillofacial Surgery, Wonkwang University College of Dentistry, Iksan, Korea .
authors: Seunghan
authors: 0000-0002-0592-7257
authors: S
authors: Oh
authors: Division of Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea .
authors: Kyung-Seok
authors: 0000-0002-9048-3805
authors: KS
authors: Hu
authors: Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea .
authors: Sungtae
authors: 0000-0001-6361-4104
authors: S
authors: Kim
keywords: BMP-2; Biphasic calcium phosphate; Bone substitute; EGCG; Hyperbaric oxygen therapy