IN VIVO EVALUATION OF A NEW BIPHASIC CALCIUM PHOSPHATE BONE SUBSTITUTE IN RABBIT FEMUR DEFECTS MODEL

Calcium phosphate ceramic has been known for its properties of bioactivity and osteoconductivity and has been widely used in orthopedic, plastic and craniofacial surgeries. The biocompatibility, unlimited availability, lower morbidity for the patient and cost-effectiveness of calcium phosphate ceramics represent important advantages over other biological bone graft, such as autografts and allografts. A new synthetic biphasic calcium phosphate (BCP), Bicera™ (60% HA and 40% β-TCP), is manufactured by Wiltrom Co., Ltd., as a new bone graft substitute. It shows good biocompatibility without cytotoxicity in in vitro test. To evaluate the possible application for clinical use, we used New Zealand white rabbit femur defect model to compare the osteoconductivity of this new bone substitute to another commercially available bone substitute (Triosite^®) which was used as the control material.

According to the macroscopic observation, both bone substitutes show good biocompatibility and no abnormal inflammation either infection was seen at the implantation sites. X-rays image of implant sites at one month, three months and six months showed all implanted materials were well incorporated with host bone. All of them were not fully absorbed and replaced after six months implantation. In the histological and hitomorphometric data, new bone grew into the surface of the peripheral pores in both bone substitutes and increased over time. Moreover, the degree of bone regeneration appeared to be relatively greater in the specimens with Bicera™ when compared with Triosite^®. We concluded that this new synthetic BCP (Bicera™) showed similar biocompatibility and osteoconductive characteristic comparing with commercial product Triosite^® in rabbit femur defects model.