Estudio in vivo de oseointegración en implantes dentales de Ti-6AI-4V con superficies modificadas.

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) UANL, 2013.

Formação e caracterização de óxidos crescidos anodicamente sobre Ti e Ti6Al4V

Foi estudada a formação e a caracterização de filmes de óxidos passivantes sobre o titânio puro e a liga Ti-6Al-4V em solução 1 M de ácido sulfúrico e em solução tampão de fosfato utilizando os métodos eletroquímicos potenciostáticos e potenciodinâmicos. Os filmes formados foram analisados via Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva (EDS), Espectroscopia Raman, Voltametria Cíclica e Espectroscopia de Impedância Eletroquímica (EIE). As análises de microscopia eletrônica de varredura mostraram que o óxido formado pode apresentar variações significativas quanto à textura e a porosidade do filme. As análises de EDS, embora não tenham mostrado a presença do oxigênio presente na composição dos óxidos, indicaram outros picos de elementos oriundos do eletrólito ou do processo de polimento e limpeza do material, além dos elementos de liga. A espectroscopia Raman não se mostrou muito adequada, para este caso, por apresentar pouca definição dos picos correspondentes aos óxidos. Os voltamogramas cíclicos, obtidos em meio ácido e em solução fosfática, apresentaram comportamentos similares onde a formação do óxido ocorre fundamentalmente durante o primeiro ciclo, enquanto que nos ciclos subseqüentes aparecem os picos catódicos de dissolução do óxido e o da reação de formação de H2, uma região de passivação e o pico anódico da reação de formação do O2. A presença de dois patamares de corrente durante o ciclo inicial sugere a formação de um filme do tipo bi-camada. Os ensaios de EIE mostraram que tanto o titânio puro como a liga de titânio tem um comportamento resistivo / capacitivo pela presença do filme de óxido na interface metal / solução, sendo que a resistência de polarização aumenta significativamente após o processo de anodização e, na maioria dos ensaios, sua ordem de grandeza foi maior que 104 kW.cm2 sugerindo que houve aumento proporcional da espessura e das características protetoras do filme formado.

Influence of the Substitutional Solute on the Mechanical Properties of Ti-Nb Binary Alloys for Biomedical Use

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Corrosion behavior of Ti-13Nb-13Zr alloy used as a biomaterial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microstructural Characterization of Ti-6Al-7Nb Alloy After Severe Plastic Deformation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microstructural Evolution of Ti-6Al-7Nb Alloy During High Pressure Torsion

Ti-6Al-7Nb alloys are being evaluated for biomedical applications, in substitution of the more conventional Ti-6Al-7V. Both types of alloys present a microstructure containing the alpha and the beta phases, which result in good compromise for mechanical applications. In the present work Ti-6Al-7Nb alloys were processed by High Pressure Torsion (HPT), varying the number of revolutions and thus the total imposed strain. X-Ray Diffraction (XRD) results revealed the formation of different crystallographic textures in samples subjected to HPT. Microhardness distribution, across the diameters of the disks, is rather homogeneous for all samples, with higher values for those subjected to 03 and 05 turns. Transmission electron microscopy (TEM) micrographs have showed that an ultra-fine grained microstructure was obtained in all the samples.

A study of histological responses from Ti-6Al-7Nb alloy dental implants with and without plasma-sprayed hydroxyapatite coating in dogs

Titanium alloys are hoped to be used much more for applications as implant materials in the medical and dental fields because of their basic properties, such as biocompatibility, corrosion resistance and specific strength compared with other metallic implant materials. Thus, the Ti-6Al-7Nb alloy that has recently been developed for biomedical use, that is, primarily developed for orthopaedic use, is to be studied in this paper, for application in dental implants. The biocompatibility test in vivo was carried out in dogs and the osseointegration was verified through histological analysis of the samples of the Ti-6Al-7Nb alloy with and without hydroxyapatite coating that were inserted in the alveoli. Within the controlled conditions the samples did not show any toxic effects on the cells. (C) 2001 Kluwer Academic Publishers.

Electrochemical impedance spectroscopy characterization of passive film formed on implant Ti-6Al-7Nb alloy in Hank's solution

The influence of potential on electrochemical behavior of Ti-6Al-7Nb alloy under simulate physiological conditions was investigated by electrochemical impedance spectroscopy (EIS). The experimental results were compared with those obtained by potentiodynamic polarization curves. All measurements were carried out in Hank's aerated solution at 25degreesC, at pH 7.8 and at different potentials (corrosion potential, 0 mV(SCE), 1000 mV(SCE), and 2000 mV(SCE)). The EIS spectra exhibited a two-step or a two-time constant system, suggesting the formation of a two-layer oxide film on the metal surface. The high corrosion resistance, displayed by this alloy in electrochemical polarization tests, is due to the dense inner layer, while its osseointegration ability can be ascribed to the presence of the outer porous layer. (C) 2004 Kluwer Academic Publishers.

Modification of surface properties of Ti-16Si-4B powder alloy by plasma immersion ion implantation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Low-frequency high-temperature internal friction in Ti-13Nb-13Zr alloy

Recent studies have been done to achieve biomedical alloys containing non-toxic elements and presenting low elastic moduli. It has been reported that Ti-Nb-Zr alloys rich in beta phase, especially Ti-13Nb-13Zr, have potential characteristics for substituting conventional materials such as Ti-6Al-4V, stainless steel and Co alloys. The aim of this work is to study the internal friction (IF) of Ti-13Nb-13Zr (TNZ) alloy due to the importance of the absorption impacts in orthopedic applications. The internal friction of this alloy produced by arc melting was measured using an inverted torsion pendulum with the free decay method. The measurements were performed from 77 to 700 K with heating rate of 1 K/min, in a vacuum better than 10-5 mBar. The results show a relaxation structure at high temperature strongly dependent on microstructure of the material. Qualitative discussions are presented for the experimental results, and the possibility of using the TNZ as a high damping material is briefly mentioned.