Experimental Study On The Reconstruction Of Thighbone Defects With Osteoid Hydroxyapatite In Rabbits

Due to congenital abnormality, trauma, tumor and inflammation, bone defect in maxillofacial region is very common. Therefore a lot of schlors devote themselves to the experimental and clinical study of bone defect reconstruction. Osteoid hydroxyapatite(OHA) is a new kind of scaffold material used in maxillofacial prosthesis and is constituted of HA and suitable compound tricalcium phosphate, with adding Na⁺ , Mg²+ and CO₃²- and high rate of porosity. All these properties let it easily dissolve with the growth of tissue in theory and benefit to adhesiveness of cells.Objective: OHA was implanted in animals to study the biocompatibility of OHA, in order to prepare for the clinical applications in the future. Methods: 12 rabbits was divided into 4 groups for study. Bone defects of 9 mm×5 mm×4 mm was made at the thighbone entocondyle of rabbits, then OHA and HA was applied to reform the defects. One group of animals were killed at 2 weeks,4 weeks,8 weeks and 12 weeks respectively to evaluate the biologic capacity with anatomy, X rays, histology, SEM and ration histology. Results: 1. OHA had better biocompatibility, and could effectively acceleratethe reconstruction of bone defects. It provided the appropriate scaffold ortemplate which would allow cellular infiltration, attachment andmultiplication.2.After OHA was implanted, inflammatory reaction was slight. Early newbone formation suggested good osteoconductivity.3. The amount of new bone increased as time elapsed. Compared with thecontrol group, more new bone formed in the left defects with OHA(P<0.05).Conclusion: OHA is a kind of bone substitute material with goodbiocompatibility. It has a potential for clinical application.