Repair of craniofacial defects with hydroxyapatite cement

Purpose: The objective of this study was to evaluate the course of healing of craniofacial bone defects when filled with hydroxyapatite cement and to determine whether adding various percentages by weight of demineralized bone powder to the cement will result in enhanced bone formation. Materials and Methods: The model for the study was the canine calvarium, The implants were placed into cranial defects and harvested at 3 or 6 months for qualitative evaluation by light microscopy, microradiography, and quantitative histomorphometry. Results: The implantation of hydroxyapatite cement resulted in characteristic replacement of the material with new bone ingrowth, The addition of demineralized bone powder to the hydroxyapatite cement appeared to improve the handling characteristics of the cement; however, improvement in the replacement of the material by bone was not observed, The implantation of only allogeneic demineralized bone showed limited new bone formation within the defect site, Conclusions: Hydroxyapatite cement formed an effective osseoconductive scaffold for bone replacement. The addition of demineralized bone powder to the cement to serve as a carrier of osseoinductive factors did not result in additional bone being formed.