Colonization of various natural substrates by osteoblasts in vitro.

The ability of osteoblasts to transfer from normal rat growing skull bone to small fragments of various biological materials was tested in an organ culture system. The substrates were tested as overlays and included intact or anorganic cut, polished or fractured bone, osteoid, cementum, dentine and enamel. Osteoblasts migrated on to and over all these materials, whether collagenous or not and whether mineralized or not. The culture medium affected the cell shape, elongation, alignment and dorsal ruffling activity of the cells similarly on the original bone surfaces and on the overlays. The position of the cells on the overlay was influenced by constraints due to space available for each cell, sharp edges and corners, and fine textural patterns, in that order. It is concluded that the ability of such substrates to support new bone formation cannot rest with the readiness of the osteoblasts to coat them. The procedures outlined constitute a valuable, simple and rapid means of testing one aspect of the biocompatibility of potential prosthetic bone implant materials.