[Comparative studies on the ingrowth behavior and the bone adhesion of various implant materials. An animal experiment].

Each of 36 mongrel dogs received implants of the following six materials: methyl methacrylate, carbon fibre composite, aluminium oxide-ceramic, titanium alloy, pure titanium and hydroxylapatite (HA). Test rods 7 mm in diameter were used to perform a push-out test, and discs with a diameter of 25 mm and a thickness of 5 mm were used for a plane traction test. The animals got a fluorochrome labelling and were harvested 8 weeks after operation. The results of the push-out test were a stability of 3.6 N/mm2 for HA and very low values for all the other materials, while the plane tension test showed a stability of 1.6 N/mm2 for the HA discs and values that were not even measurable for all the other materials. The interface of HA and the bone could not be separated by mechanical forces; usually the bone or the ceramic material fractured beneath the interface, so that the real stability of the interface must be rated very high. Light and fluorescence microscopy revealed a close bone connection for HA and only partial connections for the other materials. HA-coated materials may have a future in orthopaedics surgery.