A liga Ti-6Al4V apresenta elementos nocivos ao organismo como alumínio e vanádio, demonstrando a importância do desenvolvimento de novas ligas de Ti, com adição de elementos não tóxicos. Para a realização deste estudo, os elementos foram fundidos a arco voltaico e usinados. As amostras foram divididas em grupos sem tratamento de superfície (Grupo I) e com modificação de superfície por irradiação de feixe de laser Yb:YVO4 em duas condições: 20Hz (Grupo II) e 35Hz (Grupo III). A caracterização estrutural e microestrutural foi realizada por avaliação de módulo de Young, microscopia eletrônica de varredura (MEV) com microanálise elementar por energia dispersiva de raios X (EDX) e a Difratometria de raios X (DRX). Os resultados demonstraram uma liga de estrutura predominantemente β e formação de uma camada de óxidos de titânio sobre a superfície da liga nas três condições estudadas, indicando uma proteção do material á reações químicas em relação ao meio ao qual se expõe (NaCl 0,9%). As caracterizações apresentaram resultados favoráveis à irradiação por feixe laser, notando-se a formação de TiO2 que são importantes e responsáveis pela atração de células do tecido ósseo e interação osso/implante.   Palavras-chave: Ligas Dentárias. Titânio. Implantes Dentários. Modificações de Superfície.   Abstract The Ti-6Al-4V alloy presents elements harmful to the organism, such as aluminum and vanadium, demonstrating the importance of developing new Ti alloys with the addition of non-toxic elements. The elements were melted and machined for the study; the samples were divided into groups without surface treatment (Group I) and with surface modification by Yb: YVO4 laser beam irradiation in two conditions: 20Hz (Group II) and 35Hz (Group III). Structural and microstructural characterization was performed by evaluating Young's module, scanning electron microscopy (SEM) with elemental microanalysis by X-ray dispersive energy (EDX), and X-ray diffractometry (XRD). The results report an alloy of predominantly β structure and the formation of a layer of titanium oxides on the surface of the alloy in the three conditions studied, indicating protection of the material from chemical reactions related to its environment exposed to (NaCl 0.9%). The characterizations showed favorable results to laser beam irradiation, noting the formation of TiO2 compounds that are important and responsible for the attraction of bone tissue cells and bone/implant interaction.   Keywords: Dental Alloys. Titanium. Dental Implants. Surface Modifications.

The objective of the present study was to evaluate the corrosion resistance of the experimental alloy Ti-35Nb-7Zr-5Ta, modified by laser beam, in a physiological solution of 0.9% NaCl. This evaluation was carried out by open circuit potential analysis (EOCP), potentiodynamic polarization curves and cyclic polarization curves. The open circuit potential curves show the specimen irradiated by laser beam at 35 Hz presented a more stable and corrosion resistant surface. It was observed in the polarization curves, low current densities in the order of nA /cm2, for all specimen indicating an expected passive behavior for the investigated alloy. The cyclic polarization curves show that for specimen treated with laser, the potential for repassivation (Er) is greater in relation to the potential for corrosion (Ecorr), which indicates greater resistance to corrosion of metal alloys when treated with laser.

Titanium is a complex element and presents more than one crystallographic form, at room temperature it has a hexagonal crystal structure that transforms into a body-centered structure at 800ºC, and a melting point of 1670ºC ± 5ºC. Titanium alloys have superior mechanical properties to Ti c.p. in addition to excellent biocompatibility, a characteristic makes them the material of choice in orthopedic and dental applications. The alloy used in this study was the Ti-6Al-4V ELI alloy, obtained in cylindrical shape, sanded, and subsequently subjected to thermochemical treatment with NaOH. The physicochemical characterization was performed by the techniques of X-ray fluorescenic spectrometry (XRF), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and X-ray excited photoelectron spectroscopy (XPS). A biphasic structure (α and β) and the formation of an alkali titanate hydrogel (sodium titanate (Na2Ti5O11)) on the surface were observed, due to the reaction of the TiO2 film with the NaOH solution. It is concluded the immersion of the samples in NaOH, resulting in the crystallization of the titanate hydrogel layer, may favor the formation of calcium phosphates, as well as the bone/implant interaction.