Cellular Responses Evoked by Different Surface Characteristics of Intraosseous Titanium Implants

Figure 3

Early biological events of peri-implant bone healing include clot formation and immunoinflammatory responses. The platelets and the cells in the microenvironment produce cytokines and growth factors such as platelet derived growth factor, fibroblast growth factor, insulin growth factor, vascular endothelial growth factor, bone morphogenic proteins, interleukin-1β, and tumour necrosis factor α, some of which also recruit osteogenic precursor cells and subsequently stimulate their differentiation into osteoblasts. The fibrin based matrix of the clot is an osseoconductive medium that promotes the migration of some of the osteoprogenitor cells and endothelial progenitor cells to the implant surface. The osteoprogenitor cells and the vascular progenitor cells then differentiate into osteoblast depositing extracellular matrix which subsequently mineralizes and into endothelial cells which drive the process of neovascularization. Initially osteoblasts secrete noncollagenous bone proteins which attach to the protein conditioned layer of the implant surface. Later osteoblasts secrete collagenous precursor proteins that subsequently undergo mineralization [7].