Bone reconstructions with a hydroxyapatite and tricalcium phosphate composite: Results in rabbit models and clinical cases

Although hydroxyapatite ceramic has been clinically applied as a substitute for bone, a sintered hydroxyapatite product of greater strength has yet to be developed. However, a compound of hydroxyapatite and tricalcium phosphate, commercially known as Ceratite®, has been developed and is said to be stronger than hydroxyapatite alone. In this regard, using two sets of rabbits, the authors have investigated the biocompatibility, osteoconductivity, and effect on the bone growth of two types of Ceratite®: a dense type and a porous type. In one set of rabbits, dense-type Ceratite® grandules were deposited in an island periosteal flap. Four weeks later, it was noted that newly formed bone had achieved the original bone diameter, and that the deposits of this new bone had directly formed around the granules of Ceratite®. In the other set of rabbits, porous-type Ceratite® was implanted as inlay grafts in the tibia and the mandible and as onlay grafts on the frontal bone. Eight weeks later, the inlay grafts were completely covered by newly formed bone, and at 15 weeks, direct contact between the Ceratite® and the host bone was noted in the onlay grafts. These animal model results have shown that Ceratite® possesses excellent biocompatibility, osteoconductivity, and a growth-inducing effect. Also, the porous and dense types of Ceratite® have been clinically evaluated for use in facial skeletal surgery as a replacement for onlay and interpositional bone grafts and as a spacer to fill an iliac bone defect. In all of these clinical cases, neither an infection due to Ceratite® nor exposure of the Ceratite® occurred, and all final anatomic contours were excellent, as good as those achieved with bone grafts.