| Abstract [eng] |
The use of metal trabecular structures is increasing in order to partially restore or completely replace damaged bone tissue. This is due to the porosity of the trabecular structure, its mechanical properties and the ability to change these parameters as needed. Trabecular structures have a much larger surface area than solid structures, and thus promote the osteointegration process through the distribution of bone cells on the surface of the structure and their viability. In order to further improve the osteointegration of orthopedic implants, great attention is paid to surfaces. The surface of the orthopedic implant is the only part that comes into contact with the biological environment and affects cell adhesion, morphology, differentiation, osteoconductivity. In this work, the surfaces of Ti-6Al-4V additive manufactured alloy samples were modified using optimized sandblasting, acid-etching and alkaline technologies. Surface structural changes were evaluated using a scanning electron microscope, topographic changes and surface roughness were investigated using an optical profilometer, chemical surface composition was determined by X-ray photoelectron spectroscopy. Microcomputer tomography scans and mechanical compression studies were conducted to evaluate the effect of surface modification on porosity and mechanical properties of the trabecular structure. It has been found that by modifying the surface of the Ti-6Al-4V additive manufactured by the additive manufacturing process, granules of incompletely melted Ti-6Al-4V alloy were removed and micro- and submicron surfaces formed with sharp pits, grooves and interconnected voids. Further, the roughness value of the modified Ti-6Al-4V alloy surface was determined to be (1.92 ± 0.21) µm. The analysis of the chemical composition of this surface corresponded to the surface characteristics of orthopedic implants in scientific literature. It was also found that by modifying the Ti-6Al-4V alloy surfaces, the porosity of the trabecular structure increased from (70.27 ± 0.54) % to (78.59 ± 0.88) %, which affected the trabecular mechanical properties of the structure. It was found that the strength limit dropped from (40.81 ± 0.86) MPa to (29.01 ± 2.46) MPa, the Jung module from (1.86 ± 0.18) GPa to (1.56 ± 0.26) GPa. Comparing the results with the scientific literature, it was found that by modifying the trabecular structure the surface formed should promote cell adhesion, morphology, differentiation, osteoconductivity. However, the trabecular structure of the modified surface does not correspond to the porosity and mechanical properties stated in the literature, and is therefore not recommended for use in the manufacture of orthopedic implants to avoid additional risks. |
