Combined Delivery of Two Different Bioactive Factors Incorporated in Hydroxyapatite Microcarrier for Bone Regeneration.

BACKGROUND: The delivery of growth factors using a carrier system presents a promising and innovative tool in tissue engineering and dentistry today. Two of the foremost bioactive factors, bone morphogenetic protein-2 and vascular endothelial growth factor (VEGF), are widely applied using a ceramic scaffold. The aim of this study was to determine the use of hydroxyapatite microcarrier (MC) for dual delivery of osteogenic and angiogenic factors to accelerate hard tissue regeneration during the regenerative process. METHODS: Two MCs of different sizes were fabricated by emulsification of gelatin and alpha-tricalcium phosphate (α-TCP). The experimental group was divided based on the combination of MC size and growth factors. For investigating the in vitro properties, rat mesenchymal stem cells (rMSCs) were harvested from bone marrow of the femur and tibia. For in vivo experiments, MC with/without growth factors was applied into the standardized, 5-mm diameter defects, which were made bilaterally on the parietal bone of the rat. The animals were allowed to heal for 8 weeks, and samples were harvested and analyzed by micro-computed tomography and histology. RESULTS: Improved proliferation of rat mesenchymal stem cells was observed with VEGF loaded MC. For osteogenic differentiation, dual growth factors delivered by MC showed higher osteogenic gene expression, alkaline phosphatse production and calcium deposition. The in vivo results revealed statistically significant increase in new bone formation when dual growth factors were delivered by MC. Dual growth factors administered on a calcium phosphate matrix showed significantly enhanced osteogenic potential. CONCLUSION: We propose this system has potential clinical utility in providing solutions for craniofacial bone defects, with the added benefit of early availability.

Vertical Bone Augmentation Using Three-dimensionally Printed Cap in the Rat Calvarial Partial Defect.

BACKGROUND/AIM: Lost alveolar bone is commonly restored by distraction osteogenesis or bone blocks for substantial vertical bone augmentation (VBA), that is applied in conjunction with a barrier system. This study was performed to determine whether volume control of a three-dimensional (3D) printed nylon cap in the rat calvarial partial thickness bone defect would induce qualitative and quantitative differences in vertical bone regeneration. MATERIALS AND METHODS: A rat calvarial partial thickness bone defect was prepared and the 3D cap covered the defect to induce VBA, while the control group was left without cap placement. After six weeks the animals were sacrificed, and the calvaria were prepared for micro-CT (µCT) and histology. RESULTS: Quantitative µCT results showed that our cap system has significant osteoconductive properties, and the histology slide revealed new bone filled inside the cap. CONCLUSION: The results clearly showed that this system was successful for VBA in a research animal model.