Repair of large saddle defects of the mandibular ridge using dual growth factor release - An experimental pilot study in minipigs

Abstract

To test the hypothesis that the addition of small amounts of rhVEGF to rhBMP2 in a polymer carrier can accomplish equivalent repair effect as a reduced dosage of rhBMP2 compared to rhBMP2 alone. Defects were created bilaterally in the mandibles of 18 mini-pigs. In 12 test animals, defects were filled with 0.5g particulate PDLLA/CaCO3 composite loaded with 400μg rhBMP2/50μg rhVEGF165 on one side and 800μg rhBMP2 on the other. After 4 and 13 weeks, the animals were evaluated each for area of new bone formation (mm²) and bone density (area %). Area of newly formed bone was higher in defects with carriers loaded with 400 μg rhBMP2 50 μg VEGF165 than in defects with 800 μg rhBMP2 after 4 weeks (11.97 versus 7.97mm²; p=0.043) and 13 weeks (72.48 versus 62.2mm²; p= .028). Defects filled with blank carrier exhibited less bone after 13 weeks (42.75mm²; p= .039 and .020 respectively). Delivery of rhBMP2 from a polymer carrier can improve repair of large saddle defects of the mandibular ridge. Addition of small amounts of rhVEGF can increase bone formation and at the same time reduce the dosage of rhBMP2.