Growth/differentiation factor-5 significantly enhances periodontal wound healing/regeneration compared with platelet-derived growth factor-BB in dogs

Objective: Recombinant human growth/differentiation factor-5 (rhGDF-5) in a particulate β-tricalcium phosphate (β-TCP) carrier is being evaluated to support periodontal regeneration. The objective of this study was to evaluate periodontal wound healing/regeneration following an established clinical (benchmark) protocol including surgical implantation of rhGDF-5/β-TCP in comparison with that following implantation of recombinant human platelet-derived growth factor-BB (rhPDGF) combined with a particulate β-TCP biomaterial using an established canine defect model. Materials and Methods: Bilateral, 4 × 5 mm (width × depth), one-wall, critical-size, intrabony periodontal defects were surgically created at the mandibular second and fourth pre-molar teeth in five adult Beagle dogs. Defect sites were randomized to receive rhGDF-5/β-TCP or the rhPDGF construct followed by wound closure for primary intention healing. The animals were sacrificed following an 8-week healing interval for histological and histometric examination. Results: Clinical healing was generally uneventful. Sites receiving rhGDF-5/β-TCP exhibited a significantly enhanced cementum formation compared with sites receiving the rhPDGF construct, averaging (±SD) 4.49±0.48 versus 2.72±0.91 mm (p<0.001). Similarly, bone regeneration height and area were significantly enhanced at sites receiving rhGDF-5/β-TCP versus that of the rhPDGF construct averaging, 3.08±0.74 versus 1.29±0.78 mm (p<0.001) and 6.03±1.28 versus 2.98±2.61 mm² (p<0.01), respectively. Cementum regeneration included cellular/acellular mixed (extrinsic/intrinsic) fibre cementum at sites receiving rhGDF-5/β-TCP; sites receiving the rhPDGF/β-TCP showed a pre-dominantly acellular cementum. Newly formed cementum generally extended above the adjoining alveolar bone. Both protocols displayed β-TCP residues apparently undergoing resorption. Application of both materials appears safe, as they were associated with limited, if any, adverse events. Conclusion: rhGDF-5/β-TCP shows a significant potential to support/accelerate periodontal wound healing/regeneration. Application of rhGDF-5/β-TCP appears safe and should be further evaluated in human clinical trials.