Bone Augmentation Experiment using Coral on the Skull of Rat

[Synopsis] Bone mass growth (bone augmentation) is desirable to improve occlusal function in jaws with a decrease in bone mass. Therefore, scaffold with sufficient mechanical strength to secure space for new bone formation is needed. Since coral is a porous scaffold with mechanical strength, we tried a new method for bone augmentation using it as the scaffold. Materials and Methods: Coral disks were implanted under periosteum on the surface of rat skull. Twelve months after the implant procedure, calcein and alizarin red were administered and three days later the skull with the implanted portion was removed and the specimen was observed with a light microscope and confocal laser scanning microscope (CLSM). Results: At twelve months postoperatively, the implanted coral disks remained, while the bone augmentation was observed together with new bone formation including many osteocytes in the inner cavities of the coral disk. There were few inflammatory cells and foreign body giant cells in this area. These findings suggest that though coral disk is weakly bioabsorbable, it is a promising scaffolding material for bone augmentation on the skull.