Experimental cranioplasty and skeletal augmentation using an alpha-tricalcium phosphate/dicalcium phosphate dibasic/tetracalcium phosphate monoxide cement: a preliminary short-term experiment in rabbits.

Calcium phosphate cement consisting of alpha-tricalcium phosphate (alpha-TCP), dicalcium phosphate dibasic (DCPD) and tetracalcium phosphate monoxide (TeCP) was implanted into surgically created full-thickness defects in the cranial bone (bone defect experiment) and directly onto the cranial bone under the periosteum (augmentation experiment). Three months after the implantation, the implants were retrieved with the surrounding tissues and studied histologically and micrographically to evaluate if the cement can be used as a cranioplasty and skeletal augmentation material. In the bone defect experiment, successful reconstruction of the defect was seen in 8 out of 12 specimens. Four specimens, where bleeding control was difficult at the time of implantation, showed partial loss of the cement. Histological and microradiographic studies of the successfully implanted cement revealed that new bone surrounded the implant nearly completely and united directly with the cement surface. In the augmentation experiment, the augmented area maintained the hemispherical shape and was connected tightly with the host bone. Histology and microradiography demonstrated that new bone formation was seen in the gap between the cement and the host bone, and on the outer surface (periosteum side) of the cement at the edge of the implant. From this preliminary short-term study, it could be concluded that the cement is a promising material for cranioplasty and skeletal augmentation with indications that it has good osteoconductivity.