Osteoinduction. Part I: Test model and comparative long term observation of allogenic and xenogenic matrix implants.

In order to demonstrate osteoinductive activity of transplants and implants an experimental approach is presented in this study. Matrix induced osteogenesis following allogenic and xenogenic implantation is demonstrated morphologically, by induction of alkaline phosphatase, and by mineralisation of the newly formed matrix. Beginning on day 20 new bone formation can be found lasting up to 6 months in allogenic implants, whereas in xenogenic implants only inflammatory infiltrations are detectable. Osteoinduction is a matrix conducted phenomenon, as was confirmed by control experiments. Orthotopic allogenic implantation in diaphyseal defects of dogs demonstrates the ability of such implants to bridge a great defect by induced new bone formation and the property of the newly formed bone to adapt to physiologic stress.