The growth of the dental implant market increases the concern regarding the quality, efficiency, and lifetime of dental implants. Titanium and its alloys are dominant materials in this field thanks to their high biocompatibility and corrosion resistance, but they possess a very low wear resistance. Besides problems related to osteointegration and bacterial infections, tribocorrosion phenomena being the simultaneous action between corrosion and wear, are likely to occur during the lifetime of the implant. Therefore, tribocorrosion resistant surfaces are needed to guarantee the preservation of dental implants. This work focused on the incorporation of magnesium, together with calcium and phosphorous, in the structure of titanium oxide films produced by micro-arc oxidation (MAO). The characterization of morphology, chemical composition, and crystalline structure of the surfaces provided important insights leading to 1) a better understanding of the oxide film growth mechanisms during the MAO treatment; and 2) a better awareness on the degradation process during tribocorrosion tests. The addition of magnesium was shown to support the formation of rutile which improves the tribocorrosion properties of the surfaces.

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With the increase of elderly population and the health problems arising nowadays, such as cancer, knee and hip joint prostheses are widely used worldwide. It is estimated that 20% of hip replacement surgeries simply fail after 5years, due to wear loosening, instability and infection. In this paper it is reported the study of advanced materials with the ability to overcome some of these drawbacks. The development of ceramic coatings, based on carbonitrides of transition metals, such as TiCN, doped with silver, Ag, may represent an effective solution. Thin films of Ag-TiCN were produced by dc reactive magnetron sputtering with silver contents ranging from 4 to 8at.%. The physical, chemical, structural, morphological/topographical, mechanical and tribological properties were evaluated. The tribological tests were performed in a unidirectional wear simulator, pin on disk, being the antagonists of a ceramic Al2O3 ball, and using simulate body fluids as lubricant. Hank's Balanced Salt Solution (HBSS) and bovine serum albumin (BSA) in HBSS were chosen, in order to evaluate the lubrication ability of the solution containing the protein, albumin. The results revealed that the coatings with Ag content ranging from 4 to 8at.%, were the most promising, as the tribological properties were superior to the results reported by other authors, which also developed Ag-TiCN coatings containing similar Ag contents and using similar test conditions. The presence of albumin leads to a lower wear in all the test conditions, and this enhancement was higher in the hydrophobic surfaces.

a b s t r a c tTitanium alloys have different biomedical applications, due to their favorable mechanical, electrochemical and biological properties. However, when applied as orthopedical or dental implants, the metallic material is submitted to intense mechanical wear in a corrosive environment. In general, tribocorrosion behavior is disregarded during the development of new titanium alloys, which is focused on better mechanical or biological compatibility. In this paper, the tribocorrosion behavior of novel titanium alloys, Ti-15Zr-7.5Mo and Ti-15Zr-15Mo, for biomedical applications was investigated. Tribocorrosion tests were performed against an alumina sphere, with OCP and COF monitored during sliding. Average total wear volume was calculated by tridimensional images with confocal microscopy. The results indicated that both alloys present tribocorrosion behavior superior to cp-Ti, being abrasion the main wear mechanism. Wear volume analysis showed that the Ti-15Zr-7.5Mo presented the better tribocorrosion properties, besides the higher Young's modulus.

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