100X magnification images from the cortical region are shown. The calcium phosphate layer is resorbed slowly after implantation, thereby delaying the exposure of the underlying and faster resorbing calcium carbonate - allowing for further bone ingrowth into space previously occupied by implant. Calcium Carbonate - Underlying grey material. Bone regenerates into the macroscopic, interconnected porosity of the implant. Resorption of the implant by osteoclasts occurs where the calcium phosphate layer is perforated and the underlying calcium carbonate resorbs locally.
Abundant bone grows into the porosity and remodels.
The calcium phosphate layer, although remaining largely intact, is more perforated than at six weeks. Calcium carbonate shows substantial degradation, with bone ingrowth into the space previously occupied by calcium carbonate. Total bone volume and strength of the reconstruction increases. Normal osteonic bone has grown into both the original pore spaces and the spaces previously occupied by calcium carbonate. Regenerated bone bonds preferentially to the remaining calcium phosphate implant layers.