[Regeneration capacity of the iliac crest after spongiosa removal in humans--induction by phosphate ceramics?].

The starting point for the investigation of calcium phosphate ceramics is given by the bone regeneration, including osteo-conduction, osteo-stimulation and osteo-induction. The amount of the autogenous bone, which can be used for transplantation to induce the organo typical regeneration, is a small one. Based on animal experiments we created a standardized model for investigation of bone regeneration, using the human iliac crest. The empty iliac crest was filled by hydroxylapatite, tricalcium phosphate, Kiel bone or it remained empty as a control group. Clinical examination, X-ray control, blood chemistry and documentation were done with 104 patients divided in these four groups. Radiography, histological examination and morphometry were done with biopsies of 40 patients. The results show a bony ingrown into the ceramic material. The pores were filled by lamellar bone with new grown osteons. The ceramic granules are complete integrated. The ceramic blocks are only fixed at the edges and at the surface by bone trabeculae. The Kiel bone is surrounded by fibrous tissues without any contact to new built bone. It doesn't act as a bone substitute. The bone regeneration in the not fulfilled iliac crest was fast and of a hard quality of lamellar bone and of big amount. Both ceramics show remarkable degradation. The tricalcium phosphate brakes into pieces and shows dissolution. The hydroxylapatite in smaller particles. The degradation stopped, if the particles were surrounded by new bone. These ceramics can be used as augmentation material in combination with autogenous bone. They act as bone substitutes. The integration and bonding to new bone is complete and can be loaded by mechanical strength.