Maturation of alveolar bone following implantation of an rhGDF-5/PLGA composite into 1-wall intra-bony defects in dogs: 24-week histometric observations

Objective The aim of this study was to evaluate long-term (24 weeks) alveolar bone maturation following surgical application of recombinant human growth/differentiation factor-5 (rhGDF-5) in an injectable poly-lactide-co- glycolide-acid (PLGA) composite carrier using an established periodontal defect model. Methods Routine, bilateral, 4 × 5 mm (width × depth), 1-wall, critical-size, intra-bony periodontal defects were surgically created at the 2nd and 4th mandibular premolar teeth in 10 Beagle dogs. The animals were randomized to receive (split-mouth design; defect sites in the same jaw quadrant getting the same treatment) rhGDF-5/PLGA high dose (188 μg/defect) versus sham-surgery control (5 animals), and rhGDF-5/PLGA low dose (37 μg/defect) versus carrier control (5 animals). The animals were euthanized for histometric analysis following a 24-week healing interval. Results Clinical healing was uneventful. The rhGDF-5 high dose significantly increased bone formation compared with controls in terms of bone area (p < 0.05), and a high degree of bone maturation was observed in the rhGDF-5/PLGA high dose group. Root resorption/ankylosis or other aberrant healing events were not observed. Conclusion The rhGDF-5/PLGA appears to support alveolar bone healing/regeneration and the rhGDF-5/PLGA high dose uniquely increased maturation of the regenerated bone.