Macroporous calcium phosphate bioceramics in dog femora: a histological study of interface and biodegradation.

This study examines the biodegradation behaviour of calcium phosphate macroporous bioceramics consisting of hydroxylapatite or beta-whitlockite implants. The implantations were performed in hard tissue of femora and muscular tissue of dogs for periods of 6 and 12 month. With microradiography and light microscopy, respectively, of ground and thin sections it was shown that hydroxylapatite remained unchanged and beta-whitlockite degraded within 6 month in bone tissue. In the muscular tissue, the biodegradation of beta-whitlockite was slower. In addition, beta-whitlockite gave rise to a cellular response of lymphocytes and plasma cells rather than hydroxylapatite in the soft tissue region. For tissue response hydroxylapatite is more suitable as an implant material than beta-whitlockite.