Titanium is used in orthopedic and orthodontic implants because it has good corrosion resistance and excellent biocompatibility. Thus, studies seek to obtain a coating to improve the adhesion between the bone and the implant, by modifying the metal’s surface. The objective of this work was to biomimetically coat C.P. Ti with hydroxyapatite doped with silver nitrate, a component with antimicrobial properties, coating the metallic-ceramic composite with a polycaprolactone polymer film, which is known by generate improved implant-tissue interaction, and reducing postoperative complications from bacterial infections. The characterization of the material demonstrated the existence of the coating overall surface of the metallic substrate. The results obtained from the bacterial culture tests with Staphylococcus aureus showed that nitrate was effective in reducing the amount of live bacteria present in the supernatant, as well as those adhered to the surface of the material. In addition, the polymeric coating did not prevent the release of the bactericidal agent, not interfering in the effect there.
This work discusses on influence of niobium or molybdenum addition on microstructure and tensile properties of NiCr-based dental alloys. In this regard, the Ni-24Cr-8Nb, Ni-22Cr-10Nb and Ni-20Cr-12Nb (wt. %) alloys produced by arc melting process. To compare the typical Ni-22Cr-10Mo dental alloy was also produced. These ternary alloys were analyzed by chemical analyses, X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectrometry (EDS), thermogravimetric analysis (TG), Vickers hardness and tensile tests. Although the mass losses of the samples during arc melting, the optical emission spectrometry showed that the initial compositions were kept. The Ni-22Cr-10Mo alloy produced a matrix of Niss (ss—solid solution), whereas Ni3Nb disperse in a Niss matrix was also identified in Ni-Cr-Nb alloys. Excepting for the Ni-22Cr-10Nb alloy with mass gain of 0.23%, the as-cast Ni-Cr alloys presented mass gains close to 0.4% after heating up to 1000 °C under synthetic airflow. The hardness values, the modulus of elasticity, yield strength and ultimate tensile strength have enhanced, whereas the ductility was reduced with increasing niobium addition of up to 12 wt.-%.The Ni-22Cr-10Mo alloy presented an intergranular fracture mechanism containing deep dimples and quasi-cleavage planes, whereas the shallow dimples were identified on fracture surface of the as-cast Nb-richer Ni-Cr alloys due to the presence of higher Ni3Nb amounts.
This paper discusses on effect of molybdenum on the Ti6Si2B formation in mechanically alloyed and hot-pressed Ti-xMo-22Si-11B (x= 2, 5, 7 and 10 at%) alloys. High-energy ball milling and hot pressing were utilized to produce homogeneous and dense materials, which were characterized by scanning electron microscopy, X-ray diffraction, electron dispersive spectrometry, and Vickers hardness. The excessive agglomeration during milling was more pronounced in Mo-richer powders, which was minimized with the formation of brittle phases. Hot pressing of mechanically alloyed Ti-xMo-22Si-11B powders produced dense samples containing lower pore amounts than 1%. Ti6Si2B was formed in microstructure of the hot-pressed Ti-2Mo-22Si-11B alloy only. In Mo-richer quaternary alloys, the Ti3Si and Ti5Si3 phases were preferentially formed during hot pressing. Oppositely to the ternary phase, the Ti3Si phase dissolved a significant Mo amount. Vickers hardness values were reduced in hot-pressed Ti-xMo-22Si-11B alloys containing larger Mo amounts, which were dissolved preferentially in Ti solid solution.