title: Maturation of periodontal tissues following implantation of rhGDF-5/β-TCP in one-wall intra-bony defects in dogs: 24-week histological observations.
abstract: OBJECTIVE
  Although a previous study reported that recombinant human growth/differentiation factor-5 (rhGDF-5) coated onto a β-tricalciumphosphate (β-TCP) significantly enhanced periodontal regeneration, the long-term stability/maturation of the regenerated tissues has not been demonstrated. The objective of this study was to evaluate periodontal regeneration/maturation following application of rhGDF-5/β-TCP using an established periodontal defect model and a 24-week healing interval.
  
  
  METHODS
  Unilateral, surgically created, 4 × 4 × 5 mm (length × width × height), one-wall, critical-size, intra-bony periodontal defects at the mandibular second and fourth premolar teeth in five young adult Beagle dogs received rhGDF-5/β-TCP. Bilateral sites at the fourth premolar in the other four dogs served as pristine controls receiving mucogingival flap surgery without defect induction. The animals were euthanized at 24 weeks for histological analysis. Unpublished data from the previous 8-week study were used to compare tissue maturation between 8 and 24 weeks.
  
  
  RESULTS
  Linear histometric observations of cementum and alveolar regeneration showed no significant differences between the 8- and 24-week observation intervals. However, parameters of periodontal tissue maturation showed significant differences between the observation intervals including increased fraction mineralized tissue and lamellar bone (p < 0.05) and decreased osteocyte counts (p < 0.05) at 24 weeks compared with 8 weeks. Although the count inserting Sharpey's fibre did not significantly change, regenerated cementum remote from the intact periodontal ligament appeared more highly mineralized and thicker at 24 weeks compared with 8 weeks, and compared with the pristine cementum. Minimal β-TCP remained.
  
  
  CONCLUSIONS
  These 24-week observations suggest that regenerated periodontal tissues in sites receiving rhGDF-5/β-TCP undergo progressive maturation without debilitating aberrant tissue reactions.
authors.affiliation: Department of Periodontology, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Jung-Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
authors.forename: Jung-Chul
authors.initials: JC
authors.lastname: Park
authors.forename: Yong-Ju
authors.initials: YJ
authors.lastname: Jang
authors.forename: Susanne D
authors.initials: SD
authors.lastname: Pippig
authors.forename: Patrizia
authors.initials: P
authors.lastname: Bastone
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Chong-Kwan
authors.initials: CK
authors.lastname: Kim
mesh_terms: D020341:Absorbable Implants; D016301:Alveolar Bone Loss / Q000473:pathology / Q000601:surgery*; D000539:Alveolar Process / Q000187:drug effects / Q000473:pathology; D000818:Animals; D001672:Biocompatible Materials; D001861:Bone Regeneration / Q000187:drug effects; D002113:Calcification, Physiologic / Q000502:physiology; D002130:Calcium Phosphates; D002452:Cell Count; D003094:Collagen / Q000187:drug effects; D003739:Dental Cementum / Q000187:drug effects / Q000473:pathology; D004285:Dogs; D004846:Epithelial Attachment / Q000187:drug effects / Q000473:pathology; D055428:Growth Differentiation Factor 5 / Q000627:therapeutic use*; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008334:Mandible / Q000187:drug effects / Q000473:pathology; D010011:Osteocytes / Q000187:drug effects / Q000473:pathology; D010513:Periodontal Ligament / Q000187:drug effects / Q000473:pathology; D011897:Random Allocation; D011994:Recombinant Proteins; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; C525893:GDF5 protein, human; D055428:Growth Differentiation Factor 5; D011994:Recombinant Proteins; C485817:beta-tricalcium phosphate; D003094:Collagen