Browsing by Author "Muñoz, Roberto"
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Item Ion implantation as surface treatment for Osseointegration: From the lab to the clinic(2010) Braceras, Iñigo; Alava, Iñaki; Muñoz, Roberto; De Maeztu, Miguel Angel; INGENIERÍA DE SUPERFICIESA key process in a successful treatment of patients with a great variety of musculoskeletal implants requires a fast, reliable and consistent osseointegration. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Different surface modification techniques to improve osseointegration have been proposed and tested to date, but most focus on microscale features, and few control surface modifications at nanoscale. On the other hand, ion implantation modifies the outermost surface properties in relation to the nanotopography, chemical and physical characteristics at nanoscale. The meta-stable surface that results from the treatment, affects the adsorption of bio-molecules in the very first stages of the implant placement, and thus the signaling pathway that promotes the differentiation and apposition of osteoblast cells. This study aimed at assessing the performance, in terms of osseointegration levels and speed, of ion implanted titanium made implants. The study included several in vitro and in vivo tests. The latter, comprised different insertion periods and both experimental and commercial implants as comparative surfaces. The final stage of the study included clinical trials in human patients. In each and every case, bone integration improvement of tested materials/implants was achieved for the CO ion implanted samples. Furthermore, contact osteogenesis was observed in the ion implanted samples, unlike the Ti control samples, where only distance osteogenesis occurred, being this potentially one of the reasons for their faster healing and osseointegration process. Finally, the use of ion implantation as a surface modification tool that allows for evaluating the effects of nanotopography and composition changes independently is presented.Item Ion implantation induced nanotopography on titanium and bone cell adhesion(2014-08-15) Braceras, Iñigo; Vera, Carolina; Ayerdi-Izquierdo, Ana; Muñoz, Roberto; Lorenzo, Jaione; Alvarez, Noelia; De Maeztu, Miguel Ángel; INGENIERÍA DE SUPERFICIES; BiomaterialesPermanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40-80 keV), fluence (1-2 e17 ion/cm 2 ) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted surfaces, without surface chemistry modification, are in the same range and that such modifications, in certain conditions, do have a statistically significant effect on bone tissue forming cell adhesion.Item Microstructural, mechanical and tribological properties of CrA1YN coatings deposited by magnetron sputtering(2009) Brizuela, Marta; García-Luis, Alberto; Corengia, Pablo; González-Santamaría, Daniel; Muñoz, Roberto; González, Javier Jesús; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; GENERALCrAlYN coatings were synthesized by reactive magnetron sputtering. The aim of this research is to study the influence of the nitrogen flow at constant total gas flows on the chemical, structural and tribo-mechanical properties of the CrAlYN coatings. The nitrogen flow has an important effect on the deposition growth rate, the crystalline structure and the mechanical properties of the CrAlYN coatings. AU the coatings present a NaCl fee lattice structure but increase in the nitrogen flow changes the coating texture. Coatings morphology also changes from a columnar to an equiaxial structure. Coating hardness decreases with increase in the nitrogen flow. AU the coatings studied showed a similar tribological behaviour with a mean friction coefficient against steel between 0.47 and 0.53 without showing a clear correlation with the coatings' mechanical properties.