Augmentation of Flat Bone Area Using Tetrapod-Shaped Artificial Bone in Rats

The aim of this study was to compare bone augmentation height and mechanical strength after implantation of tetrapod-shaped granular artificial bone (Tetrabone (R) [TB]), hydroxyapatite granules [HA], alpha-tricalcium phosphate paste [P alpha] or autogenous onlay bone grafts (veneer graft [VN]). Forty-five 6-week-old male Wistar rats were used. The graft materials were implanted in the left tibial subperiosteal pocket. Bone augmentation was evaluated by computed tomography (CT), mechanical testing and histological observation immediately after surgery (0 weeks) and 4, 8, and 12 weeks later. The augmentation height was measured in CT images and the proportion of bone augmentation was calculated as the ratio of 12 weeks/0 weeks. TB aggregates were smooth in shape compared with HA aggregates. The augmentation height was significantly higher in the TB group than in the VN group. At 12 weeks, bone stiffness was significantly higher in the TB group than in the HA and P alpha groups, and very similar to that in the VN group. TB presented good shape stability and mechanical strength. TB might be useful for bone augmentation of flat bone area as compared with other currently used artificial graft materials. Future studies should focus on the clinical application of TB grafts.