Effect of Zoledronic Acid Application on Different Graft Materials in Calvarial Bone Defect Models. An Experimental Analysis.

Objective: To determine the effect of zoledronic acid on graft materials in bone calvarial defects.

Study design: Eighty adult (12 weeks) Sprague-Dawley male rats weighing from 300-350 g were divided into groups: calvarial defect, calvarial defect + synthetic graft, and calvarial defect + xenograft. All groups received zoledronate intravenously for a week after surgery and were sacrificed at either 6 or 12 weeks after their operation. The rat calvariae were fixed in 10% neutral buffered formalin before decalcification in 10% ethylenediaminetetraacetic acid for 20 days. Calvarial bone samples were then dehydrated and processed for embedding in paraffin wax. Sections 5 μm thick were stained with hematoxylin and eosin and examined by light microscopy.

Results: The effects of zoledronic acid, a third-generation nitrogen-containing bisphosphonate, on different graft materials in rats with critical-size calvarial defects were analyzed and compared. Significantly less graft resorption was identified in zoledronic acid-treated rats that had received a xenograft than in either the untreated rats or those with a synthetic graft. In the xenograft group primary ossification was visible at week 12, and the graft had entered the bone to a greater extent than in the other experimental groups or in the control group. Osseous structures were also observed more clearly in this group than in the others.

Conclusion: Zoledronic acid histopathologic bone graft stimulates bone formation. Zoledronic acid may be considered among the therapeutic methods available to improve the bone formation process in calvarial bone formation.