Abstract: Background: Ethylene oxide is widely used for secondary sterilization of bone allograft to reduce the risk of infection and associated complications. In this study the effects of ethylene oxide gas sterilization on the osteoinductivity of demineralized bone powder is investigated.
Materials and Methods: Two separate implants consisting 30 mg aseptically prepared, and 30 mg ethylene oxide-sterilized demineralized bone powder was placed into two different muscle pouches created in the paravertebral muscles of eighteen rats. After 4 weeks, they were removed with 0.5 cm normal surrounding tissue. Histological examination was done to determine the presence or absence of osteoinduction.
Results: All except one of eighteen aseptically prepared demineralized bone powder sites histologically contained new bone elements (94.4 %) and fourteen (77.7%) out of eighteen ethylene oxide sterilized demineralized bone powder sites showed evidence of new bone elements. There is no significant difference in osteoblast formation in the two groups (p>0.05).
Conclusion: It is concluded that ethylene oxide sterilization in 42˚C did not significantly reduce the osteoinductivity of demineralized bone powder. So, it can be considered as a suitable but not perfect method for secondary sterilization of demineralized bone powder.