목적: The purpose of this study is to investigate the bone formation potential of pure PCL (control) and PCL/ErhBMP-2 scaffolds, in which the mixture of ErhBMP-2 was coated on the PCL structure, in mastoid obliteration. 방법: Twenty four male SD rat weighing 250–300 g with normal eardrums were randomly divided into the PCL group (n = 12) and PCL/ErhBMP-2 group (n = 12). The ventral surface of the left side middle ear bulla was exposed and a 4 mm-sized bony hole was made with an electric drill. The middle ear mucosa was removed. Scaffolds were filled in the middle ear bulla. After the wound closure, healing occurred over 4–8 weeks. 결과: The micro-CT analysis revealed significant matrix mineralization especially in the experimental group compare to control group. The bone density in PCL/ErhBMP-2 demonstrated a high amount (p<0.005) of new bone formation with 98.8%, compared to 48.3% for the PCL group at 8 weeks. The mass of new bone formation was average 30% greater in the PCL/ErhBMP-2 group compare to the PCL group. Histological examination of the specimens using H&E stain revealed that large amounts of osteogenesis in the PCL/ErhBMP-2 group were found, but poor bone formation in the PCL group. 결론: Bone formation was found in the defects of the pure PCL scaffold and PCL/ErhBMP-2 coated groups. However, PCL/ErhBMP-2 groups presented faster and more effective osteogenesis at the defect area than pure PCL scaffolds. These results indicate that the ErhBMP-2 in the composite scaffolds could promote osteogenesis in vivo. The role of ErhBMP-2 in the promotion of bone formation in vivo might be due to its ability to enhance surface properties, including increasing the surface.