Papers by Author: F.F. Mitri

Abstract: Biomaterials for treatment of bone defects have been studied for a long time. Alloplastic materials, mainly hydroxyapatite (HA), are under intense investigation due to its biocompatibility and osteoconductive properties. The HA can be modified by the incorporation of bivalent cations as Zn2+ known as a positive effectors for bone repair. The purpose of this study was to evaluate comparatively the effectiveness of 5% zinc-containing hydroxyapatite (ZnHA) in the treatment of critical size defect (CSD) in rat’s calvaria. CSD (8mm diameter) created in the skull of forty-five Wistar rats were filled with autogenous bone, HA and ZnHA. Skulls harvested after 30, 90 and 180 days were submitted to histological processing for paraffin embedding. Sections of 5 µm-thick stained with hematoxylin and eosin (HE) allowed histomorphometric analysis. The area of neoformed bone increased (p<0.001) from 30 to 180 days irrespective to treatment groups. ZnHA and the control group showed a large at 180 days but no significant difference compared to HA. Therefore, we concluded that both biomaterials are biocompatibles and osteoconductors, promoting new bone formation and apposition of bone on the surface throughout the periods and the addition of zinc improved the osteogenesis.

Abstract: Hydroxyapatite (HA), widely used as bone graft, can be modified by the incorporation of bivalent cations (Mg2+ and Zn2+) and its gradual release could favor the bone repair. The purpose of this research was to evaluate the effect of the HA and zinc-containing hydroxyapatite (Zn-HA) in the bone repair in rat calvaria in comparison to autogenous bone. Critical size defect in the calvaria was filled with the graft material and the samples were harvested at the 30, 90 and 180 days. The light microcopy observations showed the biocompatibility of the graft materials. In the Zn-HA group the area of neoformed bone was larger than in the HA group, but smaller than in the autograft. A fibrous connective tissue was more evident around HA granules. It could be conclude that the presence of zinc ions in HA crystal accelerated the osteogenesis and increased the area of newly formed bone in relation to HA.