Osteogenesis associated with a mixture of hydroxyapatite and autogenous calvarial periosteum implanted in muscle tissue

The purpose of this study is to evaluate the role of hydroxyapatite (HA) in the process of osteogenesis. Composite grafts of HA (particles and porous column) and autogenous calvarial periosteum were implanted into the back muscle of 12 rabbits. HA alone and periosteum alone were also implanted as control. Three and 6 months after implantation, the grafts were retrieved and evaluted histologically and microradiographically. There was no significant difference between 3-and 6-month implant periods in any implant group.No calcified tissue was formed when HA alone (both particles and porous column) was implanted. Minute calcified tissues were scattered in the histologic and microradiographic specimens of periosteum alone or particulate HA/periosteum grafts. On the other hand, bone tissue was noted in the specimens of porous-columnar HA/periosteum grafts. Bone tissue was seen only inside of the pores where it adhered intimately to the HA wall of the pores.Although the role of HA in the osteogenic process was not defined in this study, it is very interesting that different calcified tissues were induced by the particulate and porouscolumnar HA/periosteum grafts.