Comparative Evaluation of Bone Regenerating Capacity Using Nanocrystalline Hydroxyapatite and Coral Composite: A Canine Model Study

Natural and synthetic graft materials have been studied in vivo and in vitro in osseous tissue repair. This study was carried out to investigate and compare the ability of the nanohydroxyapatite (Nano-HA) and coral composite (C-co composite) containing coral, gelatin and chitosan to induce new bone growth when implanted in a critical size defect in canine tibia. Fifteen adult mongrel dogs were used in this study. Groups 1, 2, 3, 4 and 5 were investigated after 2, 4, 8, 16 and 24 weeks, respectively. Three holes (10 mm diameter) were made at the upper third of the tibia. The first hole was implanted with C-co composite, the second one was left empty; while, the third hole was filled with Nano-HA. Healing of the implanted holes was evaluated using sequential radiography and histopathological evaluation at the end of each observation period. The holes implanted with C-co composite and Nano-HA were filled with mature compact bone; on the other hand, the control holes were filled with dense connective tissue. Both C-co composite and Nano-HAP behaved in a similar manner concerning their pattern of resorption. In conclusion, addition of chitosan and gelatin to coral improves its osteoinductive properties. Furthermore, both C-co composite and Nano-HA had a similar pattern for formation of new bone when used to fill critical size bone defect in canine tibia. C-co composite is cheap, available, easily prepared and can replace Nano-HA in bone grafting.