AN ANIMAL STUDY ON THE BONE BEHAVIOR OF CA-P-COATED IMPLANTS - INFLUENCE OF IMPLANT LOCATION

Four different implant materials were installed into the mandibular co rner of goats to investigate the trabecular bone response in a mainly unloaded model. The implants were installed using a standardized techn ique and were left in situ for 12 weeks. One goat had to be sacrificed after surgery because of a broken rib; the other animals healed uneve ntfully. After sacrifice of the animals, the bone response to the unco ated and the three different Ca-P implants was evaluated histologicall y and histomorphometrically. Four sections of each implant were evalua ted; two were located in the cortical and two in the trabecular bone. Of the 44 retrieved implants, 20 implants appeared to be installed par tially in the mandibular canal, as clearly visible on the X-rays. Thes e implants were not used in the histomorphometrical measurements. Hist ological evaluation showed that the trabecular and cortical bone react ions were similar; there was no significant difference in the percenta ge of bone contact nor in the amount of bone in contact with the impla nts. In conclusion this study showed that the mandibular corner is an unsatisfactory model for the installation of implants because of anato mical restrictions. Also, the experiment remained inconclusive about t he influence of loading conditions on bone behaviour. Nevertheless, th e histological results confirmed the bioactive properties of Ca-P coat ings.