In vivo study of a calcium phosphate cement consisting of alpha-tricalcium phosphate/dicalcium phosphate dibasic/tetracalcium phosphate monoxide.

Prehardened calcium phosphate cement consisting of alpha-tricalcium phosphate (alpha-TCP), dicalcium phosphate dibasic (DCPD) and tetracalcium phosphate monoxide (TeCP) was implanted in rabbit mandibles and back muscles, and studied histologically and microradiographically. In the mandibles, new bone formation occurred around the implants and increased in quantity the longer the implant period lasted. Histology, microradiography and scanning electron microscopy (SEM) demonstrated direct contact of bone and cement. Bone response to this cement was essentially the same as to hydroxyapatite (HA) ceramics, known as a biocompatible bone substitute. Material resorption was recognized, which increased with the implant period and was greater in the surface bound by soft tissue than the surface bound by bone tissue. In the back muscles, however, no calcified tissue formation occurred. Resorption proved to be faster than in the case of the mandible implants. It was concluded that the cement, in prehardened form, has good biocompatibility and is a promising material as a bone substitute.