title: Prognostic factors for alveolar regeneration: osteogenic potential of resident bone.
abstract: OBJECTIVE
  There is a limited understanding of the role of resident bone in periodontal regeneration. The objective of this study was to evaluate the influence of the resident alveolar bone on bone regeneration in conjunction with guided tissue regeneration (GTR) in the presence or the absence of cell occlusivity.
  
  
  METHODS
  Critical-size, 6-mm, supra-alveolar periodontal defects were created in six young adult Beagle dogs. Space-providing, occlusive or porous expanded polytetrafluaroethylene devices were implanted to provide for GTR. Treatments were alternated between left and right jaw quadrants in subsequent animals. The gingival flaps were advanced for primary intention healing. The animals were euthanized at week 8 postsurgery. The histometric analysis assessed regeneration of alveolar bone relative to space-provision by the GTR device and width of the alveolar crest at the base of the defect.
  
  
  RESULTS
  There were no significant differences in mean alveolar regeneration between sites receiving the porous GTR device with a narrow versus a wide alveolar ridge after adjusting for wound area (2.22 versus 2.50 mm, respectively; p=0.36). In contrast, analysis using sites receiving the occlusive GTR device revealed significantly greater bone regeneration at sites with a wide compared with a narrow alveolar ridge (3.34 versus 2.53 mm, respectively; p=0.02). Regression analysis showed a significant relationship (p< or =0.05) between space-provision and bone regeneration for all groups except for sites with a wide alveolar ridge receiving the occlusive GTR device (p=0.5).
  
  
  CONCLUSIONS
  The resident alveolar bone may significantly influence the magnitude of alveolar bone regeneration. The relative presence of cells from the gingival connective tissue may attenuate this effect.
authors.affiliation: Laboratory for Applied Periodontal and Craniofacial Regeneration, Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA 19140, USA. gpolimeni@hotmail.com
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Polimeni
authors.forename: Jasim M
authors.initials: JM
authors.lastname: Albandar
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
mesh_terms: D016301:Alveolar Bone Loss / Q000628:therapy*; D000818:Animals; D001861:Bone Regeneration; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000295:instrumentation; D008297:Male; D010012:Osteogenesis; D011379:Prognosis; D012044:Regression Analysis