Prognostic factors for alveolar regeneration:: osteogenic potential of resident bone

Objectives: 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 (pless than or equal to0.05) 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.