Abstract
The objective of this study was to estimate bone induction by a bioabsorbable hydroxyapatite block (functionally graded hydroxyapatite: fg-HAp, 3×3×3 mm)/rhBMP-2 (5 μg) on rat skull periosteum, the absorption of fg-HAp, compared with non-absorbable hydroxyapatite (BONECERAM®). In the fg-HAp/BMP-2, bone formation started in the outer layer of the ceramics at 1 week after implantation and induced bone was found in the middle part at 4 weeks. In both the fg-HAp alone and the fg-HAp/BMP-2 groups, body fluid permeated into the bulk of fg-HAp scaffold and then fg-HAp block was gradually fragmented by autodegradation and bio-absorption. On the other hand, in the non-absorbable HAp/BMP-2, bone was found locally in the surface layer of the HAp at 4 weeks. In the fg-HAp alone and the non-absorbable HAp alone, bone formation never occurred in this model.
Therefore, our fg-HAp is an bio-absorbable ceramic and the fg-HAp/BMP-2 supra-periosteal implant might be a superior bone reservoir system.
