The aim of this study was to examine the combination effects of immobilization of PDGF-BB and BMP-2 onto heparinized-Ti implant on in vitro osteoblast function and in vivo osseointegration and vertical augmentation of the alveolar ridge.
Method:
Successful immobilization of PDGF-BB and/or BMP-2 onto heparinized-Ti (Hep-Ti) was confirmed by SEM and XPS, and the two growth factors were released in a sustained manner. For evaluating osteoblast function, we also investigated cell viability and proliferation, ALP activity, calcium deposition, and mRNA expression of osteocalcin and osteopontin. Furthermore, the PDGF-BB and/or BMP-2-immobilized Hep-Ti implants were inserted into beagle dogs, and the implant stability quotient (ISQ), bone mineral density, bone volume, osseointergration and bone formation were evaluated with micro CT and histological examination.
Result:
The in vitro studies revealed that osteoblasts grown on PDGF-BB and BMP-2 immobilized Hep-Ti had a significant increment in ALP activity, calcium deposition, osteocalcin and osteopontin levels as compared to those grown on PDGF-BB alone- or BMP-2 alone-immobilized Hep-Ti. The in vivo study showed that osseointegration and bone formation in PDGF-BB and BMP-2-immobilized Hep-Ti was greatly enhanced as compared to that in PDGF-BB-immobilized Hep-Ti. PDGF-BB and BMP-2 immobilized Hep-Ti also displayed improved implant stability, bone volume around the defect area, and intra-thread bone density (ITBD) as compared to BMP-2-immobilized Hep-Ti, but no significant differences were seen between the two groups.
Conclusion:
We concluded that the combination effects of immobilization of PDGF-BB and BMP-2 onto Ti on bone formation and regeneration were better. Further optimization studies are needed to achieve more affirmative synergistic outcomes of the two growth factors in implant surgery.