Titanium Powder Coating Using Metal 3D Printing: A Novel Coating Technology for Cobalt–Chromium Alloy Implants
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Three-dimensional (3D) printing with a direct metal fabrication (DMF) technology has been innovatively introduced in the field of surface treatment of prostheses. The purpose of this study was to determine whether such modifications on the surface of cobalt–chromium (CoCr) alloy by titanium powder coating using DMF improves the osseointegration ability of CoCr alloy.
We compared the in vitro and in vivo ability of cells to adhere to DMF-coated CoCr alloy with machining. Biological and morphological responses to human osteoblast cell lines were examined by measuring cell proliferation rate and observing expression of actin filament. For in vivo study, we inserted different specimens in each medulla of the distal femurs of rabbit. After 3 months, the distal femurs were harvested, and a push-out test and histomorphometric analyses were performed.
The cell proliferation rate and cell adhesion in the DMF group were higher compared with those in the machined group. Human osteoblast cells on the DMF-coated surface were more strongly adhered and well-proliferated compared with those on the other surface. In the in vivo test, there was a significant difference in the ultimate shear strength between the DMF and machined groups (2.49 MPa vs. 0.87 MPa, respectively, p = 0.001). In the histomorphometric analysis, there was a significant difference in the mean bone-to-implant contact percentages between the DMF and machined groups (72.3 ± 6.2% vs. 47.6 ± 6.9%, respectively, p < 0.001).
Titanium coating of CoCr alloy with 3D metal printing provides optimal surface characteristics and a good biological surface both in vitro and in vivo.
KeywordsCobalt–chromium alloy Direct metal fabrication Osseointegration Surface treatment 3D printing
This study was supported by the Advanced Technology Center project (10048394) from the Korea Evaluation Institute of Industrial Technology (KR). The Catholic master cells supplied by the Catholic Institute of Cell Therapy (CIC, Seoul, Korea) were derived from human bone marrow donated by healthy donors after informed consent.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The animal experiment procedures were approved by the institutional animal care and use committee of The Catholic University of Korea (CUMC-2014-0109-03).
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