However, this method could cause (1) structural deformation, (2) delamination of the coated surface, (3) non-optimal porosity, (4) decrement in fatigue strength, and (5) relatively high-cost and complexity of the process. It has been known for its versatility in application and availability. Plasma spraying is an established, commercially available method used in the additive manufacturing (AM) process. Thus, it had been considered as a challenge to create cobalt-chromium and titanium alloy with conventional techniques. The configuration of the end-product, whether there be a groove or an angle is a significant variable to the process. The additive manufacturing process is known to be dependent on types of metals, and titanium itself poses a challenge to the process due to its high melting point and chemical composition. To create or combine metal on the metal surface, casting or forging plus additive manufacturing processes are required. While it has been known that titanium surface coating on cobalt-chromium (CoCr) alloy would yield such quality, this process had remained challenging. Until now, endeavor to meet the optimal surface condition for implants to incorporate such characteristics is ongoing. Strength, osteointegrative capability, and biocompatibility are the qualities desirable for an orthopedic implant. The resulting product of the surface shows a similar quality to that of the plasma spraying method, both in vivo and in vitro, in terms of biological and mechanical property. In conclusion, DMF is a method which can reliably create a proper titanium surface on CoCr alloy. Histomorphometry analysis also showed a similar result ( p = 0.657). The biomechanical push-out test yielded a similar result ( p = 0.714). Expression and distribution of fibronectin and Runx-2 genes showed similar degrees of expressions. The proliferation of the osteoblasts, the DMF group showed a better result at different optic density levels ( p = 0.035, 0.005, 0.001). Resultįor cell morphology observation, lamellipodia and filopodia, a cytoplasmic projection extending into porous structure, formed on both surfaces created by DMF and TPS. The rods were biomechanically tested with a push-out test and observed for histomorphometry to evaluate the microscopic bone to implant ratio. For in vivo study, coated rods were inserted into the distal femur of the rabbit and then harvested. Cellular proliferation was validated with ELISA, immunofluorescent assay. Cellular morphology was observed with a scanning electron microscope. Methodįor in vitro study, human osteoblast cells were seeded onto the coated surfaces. For this, we compared characteristics of titanium-coated surfaces created by direct metal fabrication method (DMF) and titanium plasma spraying (TPS), both in vitro and in vivo, for (1) cell morphology, (2) confocal microscopy images of immunofluorescent assay of RUNX2 and fibronectin, (3) quantification of cell proliferation rate, (4) push-out biomechanical test, and (5) bone histomorphometry. We hypothesized that this would yield a coated surface quality as acceptable or better than the already established method of plasma spraying. In our study, we utilized additive manufacturing with a 3D printing called direct metal fabrication (DMF) and compared it to the plasma spraying method (TPS), to coat titanium onto CoCr alloy. Creating such a coated surface takes a challenging process and two dissimilar metals are not easily welded. Titanium surface coating on cobalt-chromium (CoCr) alloy has characteristics desirable for an orthopedic implant as follows: strength, osteointegrative capability, and biocompatibility.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |