Comparative study and histomorphometric analysis of bone allografts lyophilized and sterilized by autoclaving, gamma irradiation and ethylene oxide in rats

To compare three sterilization methods (autoclave, gamma irradiation and ethylene oxide) over non demineralized lyophilized bone allografts. Bone allografts were implanted on paravertebral muscles of 21 rats. After 30 days animals were sacrificed and grafts underwent comparative analysis regarding histomorphometric and macroscopic parameters. Allografts that underwent the three sterilization methods presents similar weight gain, cortical thickness similar to control group, and less fibrosis than the control group. Grafts that underwent sterilization in autoclave presented less presence of multinucleated giant cells, although not statistically significant. There was also no statistically significant difference regarding mineralization on the three groups. The three sterilization methods cause similar effects on bone allografts regarding macroscopic and histomorphometric parameters.