IN-VIVO STUDY OF CALCIUM-PHOSPHATE CEMENTS - IMPLANTATION OF AN ALPHA-TRICALCIUM PHOSPHATE DICALCIUM PHOSPHATE DIBASIC TETRACALCIUM PHOSPHATE MONOXIDE CEMENT PASTE

alpha-Tricalcium phosphate (alpha-TCP)/dicalcium phosphate dibasic (DC PD)/tetracalcium phosphate monoxide (TeCP) cement was implanted in pas te form into soft tissue (rate subcutaneous sockets) and bone tissue ( defects in rabbit mandibles) to evaluate the setting behaviour of the cement and tissue responses to the cement. A histological study of the soft tissue implants revealed thin fibrous capsule formation, the app earance of multinucleated giant cells on and close to the cement surfa ce, and small clusters of the cement near the main part of the set cem ent which were formed by the migration of the paste while setting. X-r ay diffraction (XRD) analysis of the implanted cement showed peaks for hydroxyapatite (HA) which increased as the implant period increased. Histology and microradiography of the bone tissue implants showed well -set cement without migration, active bone formation around the cement and direct bone union to it. However, the cement disappeared from the implant site in 4 of 16 specimens where intense bleeding seemed to wa sh away the implants while setting. From the results of the present st udy, we concluded that the cement is well tolerated, especially by bon e tissue. This may be related to the fact that the cement sets produci ng HA. The cement is a promising material as a bone substitute; howeve r, there is a problem of migration while setting in soft tissue and of exclusion from the bone defects by intense bleeding. (C) 1997 Elsevie r Science Limited.