Treatment of Bone Defects in Rabbit Tibiae using CaO-SiO2-P2O5-B2O3 Bioactive Ceramics: Radiological, Biomechanical, and Histological Evaluation

Many calcium phosphate ceramics have been developed as bone graft Substitutes to treat bone defect. Bioactive glass ceramics have been improved in terms of mechanical strength and bioabsorbance. The purpose of this study was to compare bone binding capacity of hydroxyapatite and bioactive ceramics made by CaO-SiO2-P2O5-B2O3(Bonglass 6, 7). Bioactive ceramics(Bonglass 6, 7) or hydroxyapatite plates of 5 mm height were inserted to tibial bony defect of New Zealand white rabbits weighing 3-3.5 kg. Total number of rabbits was 36 and divided into 3 groups randomly. Bony binding and fusion capacity were evaluated through the radiological study every 2 weeks. 12 weeks after surgery gross examination, manual palpation, biomechanical and histological studies were made. Seven rabbits in all group died during breeding but in autopsy finding, there was no evidence suggesting infection or graft rejection. Fusion rates were 77.8%(7/9) in Bonglass 6 group, 80%(8/10) in Bonglass 7group, and 70%(7/10) in hydroxyapatite group. Mean values of the tensile strengths were 126.3 +/- 74.6 N in Bonglass 6 group, 136.6 +/- 77.2 N in Bonglass 7 group, and 135.6 +/- 113 N in hydroxyapatite group. In histological analysis of 2 specimens from each group, porous hydroxyapatite group showed slightly better bone binding capacity. Bonglass and hydroxyapatite group showed similar bone binding capacity and there was no statistically significant difference between 3 groups.