Osteoconduction on, and bonding to, calcium phosphate ceramic implants

Calcium phosphate ceramic blocks of three different densities (porous, intermediate and dense) were prepared by tape casting and implanted in the femora of 9 Wistar rats for 1-3 weeks. Following fixation, the tissue was prepared for examination by scanning electron microscopy of freeze fractured specimens, or backscattered electron imaging of polymethylmethacrylate embedded, undecalcified sections, and all the ceramics were found to be osteoconductive. In all the examined implants, de novo bone formed on the ceramic surface by the initial production of biological cement-line like interfacial extracellular matrix, and the results show that osteoconduction and bone-bonding are distinct mechanistic phenomena.