Wound healing and formation of woven bone
Stage 1: Wound healing and formation of woven bone (callus) (2 to 6 weeks)
The ability of the body to respond to the "trauma" induced by implantation will influence the kind of tissue response (and hence the degree of integration). Therefore proper surgical handling of the tissues with minimal generation of heat (<47º C for 1 minute or less) during preparation of the surgical site will provide the most predictable healing response.
After the formation of initial clot around the surgical site, a minor inflammatory response occurs which includes the proliferation and differentiation of numerous phagocytes and undifferentiated mesenchymal cells from the adjacent periosteum. The ability of the tissues to differentiate will depend on the presence of an intact vascular bed that provides adequate oxygenation for bone differentiation.
With the initial placement of the implant, a thin (about 0.5mm) layer of bone in the prepared site will become necrotic from the process of forming the implant site. This bone is replaced by the body as integration proceeds. Initially, an in growth of vascular loops will occur at the rate of 0.5mm per day followed by initial woven bone formation in the first two weeks after initial surgical implant placement. Due to the inert nature of the oxide surface, newly differentiating osteoblastic cells derived from the adjacent periosteum synthesizes woven bone matrix that provides initial bone contact with the oxide surface.