This matrix bond increases in strength over time, promoting reparative osteogenesis at the interface that results in clinical fixation of the implant.
Direct contact between living bone and the surface of a load-carrying titanium implant forms a strong structural and functional extracellular matrix (ECM) bond at the interface that is composed of proteoglycans, glycoproteins, and adhesion molecules. The remarkable success of endosteal titanium implants in dental, cranial-maxillary facial reconstruction, and orthopedic applications can be attributed to the capability of pure titanium implants to become permanently integrated with living bone, a phenomenon defined as osseointegration. Key words: bone, endosteal, histopathology, intramedullary, matrix, MMP, osseointegration, TIMP, titanium, TNF. Our data link titanium-induced bone remodeling to changes in expression and distribution of MMPs. These findings were not seen in contralateral or sham-operated bone, where the titanium fixtures were threaded into the femur and immediately removed. An increase in TIMP-3, MMP-9, and MMP-7 in hypertrophied chondrocytes and the vascular component of the epiphysial growth plate was also observed in experimental bone. We observed dramatic increases in MMP-2, MMP-9, MMP-7, TIMP-3, and TNF-alpha in osteocytes, osteoclasts, haversian canals, and the interface matrix in bone ipsilateral to the titanium implant. In this study, we used a rodent femur model of intramedullary osseointegration to analyze the changes in immunoreactivity of ECM-controlling matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase-3 (TIMP-3), and tumor necrosis factor alpha (TNF-alpha) during osseointegration. Abstract - Implanted pure titanium fixtures are able to completely integrate with bone, in part because of the formation of a strong extracellular matrix (ECM) bond at the titanium-bone interface.