[The effects of microwave heating on osteoinduction of demineralized bone matrix in rabbits]

In order to study the change of the autograft demineralized bone matrix, twenty-four new-Zealand rabbits were randomly divided into four groups of 2, 4, 8, 12 week by sacrified time, each group had 7, 7, 5, 5 rabbits. Autoradiography was done for 2 rabbits in 2, 4 weeks respectively. The tibiae were removed by amputation at knee joint level, then they were cleansed of marrow and periosteun, cut into six pieces in length of 0.8 cm heated with microwave. Demineralized bone matrix were made by defated and decalcified, and implanted into abdomenal walls autograft. The results showed that the implants heated at 45 degrees C 30 min had same osteoinduction as control group. The 65 degrees C 30 minutes heating may reduce implant's osteoinduction slightly. The osteoinduction of the groups heated 75 degrees C for 30-60 minutes were impaired severely. The implants boiled at 100 degrees C 30 minuts had no osteoinduction at all, 65 degrees C 30 minutes may be a "safty" limit when heat treatment on bone clinically. Otherwise, bone formation ability would be reduced and remodelling was delayed.