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The nature of the electronic ground state of the Ti2C MXene is unambiguously determined by making use of density functional theory-based calculations including hybrid functionals together with a stringent computational setup providing numerically converged results up to 1 meV. All the explored density functionals (i.e., PBE, PBE0, and HSE06) consistently predict that the Ti2C MXene has a magnetic ground state corresponding to antiferromagnetic (AFM)-coupled ferromagnetic (FM) layers. A spin model, with one unpaired electron per Ti center, consistent with the nature of the chemical bond emerging from the calculations, is presented in which the relevant magnetic coupling constants are extracted from total energy differences of the involved magnetic solutions using an appropriate mapping approach. The use of different density functionals enables us to define a realistic range for the magnitude of each of the magnetic coupling constants. The intralayer FM interaction is the dominant term, but the other two AFM interlayer couplings are noticeable and cannot be neglected. Thus, the spin model cannot be reduced to include nearest-neighbor interactions only. The Néel temperature is roughly estimated to be in the 220 ± 30 K, suggesting that this material can be used in practical applications in spintronics and related fields.

Additive manufacturing (AM) enables fully dense biomimetic implants in the designed geometries from preferred materials such as titanium and its alloys. Titanium aluminum vanadium (Ti6Al4V) is one of the pioneer metal alloys for bone implant applications, however, the reasons for eliminating the toxic effects of Ti6Al4V and maintaining adequate mechanical strength have increased the potential of commercially pure titanium (cp-Ti) to be used in bone implants. This literature review aims to evaluate the production of cp-Ti and Ti6Al4V biomedical implants with laser powder bed fusion (L-PBF) technology, which has a very high level of technological matureness and industrialization level. The optimization of L-PBF manufacturing parameters and post-processing techniques affect the obtained microstructure leading to various mechanical, corrosion and biological behaviors of the manufactured titanium. All of the features are considered in the light of specifications and needs of bone implant applications. The most critical disadvantages of the L-PBF technology, such as residual stresses and leading deformations are introduced and the potential solutions are discussed. Moreover, the manufacturability of porous bone implants that causes benefit and harm in L-PBF applications are assessed. Peer Reviewed Objectius de Desenvolupament Sostenible::3 - Salut i Benestar

The synthesis, properties, and reactivity of monocyclopentadienyltitanium(III) complexes stabilized by hydridoborato (BH3R)(-) ligands are reported. The reactions of the titanium(IV) trichlorides [Ti(eta(5)-C5H5-nMen)Cl-3] with excess LiBH3R (R = H, Me) afford dimeric [{Ti(eta(5)-C5H5-nMen)(BH4)(mu-BH4)}(2)] (n = 5 (1), 4 (2), 0 (3)) or monomeric [Ti(eta(5)-C5Me5)(BH3Me)(2)] (4) titanium(III) derivatives. Compound 3 is a thermally unstable oil and decomposes at room temperature forming a mixedvalence Ti-II/Ti-III tetrametallic species [{Ti(eta(5)-C5H5)(BH4)}(2){(mu(3)-B2H6)Ti(eta(5)-C5H5)}(2)] (5) with dianionic diborane(6) ligands in a rare mu(3)-kappa(2):kappa(2):kappa(2)-B2H6 coordination mode. Density functional theory (DFT) calculations for 5 agree with a triplet ground state with two inner titanium(II) atoms bonded by a single bond and two outer titanium(III) centers. In contrast to 3, the monomeric tetrahydrofuran adduct derivative [Ti(eta(5)-C5H5)(BH4)(2)(thf)] (6) is a stable solid. Dimeric 1-3 react with 2,6-lutidinium salts (LutH)X (X = BPh4, OSO2CF3) to afford ion pairs, [Ti(eta(5)-C5H5-nMen)(BH4)L-2](BPh4) (L = thf, n = 5 (7), 4 (8), 0 (9); L = py, n = 5 (10)), or molecular aggregates, [{Ti(eta(5)-C5Me5)(BH4)(mu-O2SOCF3)}(2)] (11) and [{Ti(eta 5C5H5-nMen)(mu-O2SOCF3)(2)} x] (n = 5, x = 3 (12); n = 4, x = 4 (13)), via formation of H-2 and (Lut)BH3. Diamagnetic titanium(II) derivatives [{Ti(eta(5)-C5Me5)(mu-H)}(2){(mu-H)(2)Al(BH3R)(thf)}(2)] (R = H (14), Me (15)) were isolated in reactions of complexes 1 and 4 with LiAlH4 in tetrahydrofuran., Spanish Structures of Excellence María de Maeztu, Ministerio de Ciencia, Innovación y Universidades, Universidad de Alcalá

The surface topography of titanium dental implants has a great influence on osseointegration. In this work, we try to determine the osteoblastic behavior and gene expression of cells with different titanium surfaces and relate them to the physicochemical properties of the surface. For this purpose, we have used commercial titanium discs of grade 3: as-received corresponds to machined titanium without any surface treatment (MA), chemically acid etched (AE), treated via sand blasting with Al2O3 particles (SB) and a sand-blasting treatment with acid etching (SB+AE). The surfaces have been observed using scanning electron microscopy (SEM) and the roughness, wettability and surface energy with dispersive and polar components have been characterized. Osteoblastic cultures were performed with SaOS-2 osteoblastic cells determining cell viability as well as alkaline phosphatase levels for 3 and 21 days, and osteoblastic gene expression was determined. The roughness values of the MA discs was 0.02 μm, which increases to 0.3 μm with acid attack and becomes the maximum for the sand-blasted samples, reaching values of 1.2 μm for SB and SB+AE. The hydrophilic behavior of the MA and AE samples with contact angles of 63° and 65° is superior to that of the rougher samples, being 75° for SB and 82° for SB+AE. In all cases, they show good hydrophilicity. GB and GB+AE surfaces present a higher polar component in the surface energy values, 11.96 and 13.18 mJ/m2, respectively, than AE and MA, 6.64 and 9.79 mJ/m2, respectively. The osteoblastic cell viability values at three days do not show statistically significant differences between the four surfaces. However, the viability of the SB and SB+AE surfaces at 21 days is much higher than that of the AE and MA samples. From the alkaline phosphatase studies, higher values were observed for those treated with sand blasting with and without acid etching compared to the other two surfaces, indicating a greater activity in osteoblastic differentiation. In all cases except in the Osterix (Ostx) —osteoblast-specific transcription factor—a decrease in gene expression is observed in relation to the MA samples (control). The most important increase was observed for the SB+AE condition. A decrease in the gene expression of Osteoprotegerine (OPG), Runt-related transcription factor 2 (Runx2), Receptor Activator of NF-κB Ligand (RANKL) and Alkaline Phosphatase (Alp) genes was observed in the AE surface.

The rapid integration in the bone tissue and the prevention of bacterial infection are key for the success of the implant. In this regard, a silver (Ag)-doped thermochemical treatment that generate an Ag-doped calcium titanate layer on titanium (Ti) implants was previously developed by our group to improve the bone-bonding ability and provide antibacterial activity. In the present study, the biological and antibacterial potential of this coating has been further studied. In order to prove that the Ag-doped layer has an antibacterial effect with no detrimental effect on the bone cells, the behavior of osteoblast-like cells in terms of cell adhesion, morphology, proliferation and differentiation was evaluated, and the biofilm inhibition capacity was assessed. Moreover, the competition by the surface between cell and bacteria was carried out in two different co-culture methods. Finally, the treatment was applied to porous Ti implants to study in vivo osteointegration. The results show that the incorporation of Ag inhibits the biofilm formation and has no effect on the performance of osteoblast-like cells. Therefore, it can be concluded that the Ag-doped surface is capable of preventing bone bacterial infection and providing suitable osseointegration.

[ES] Las aleaciones de Titanio (Ti) tienen una gran importancia en numerosas industrias. En particular, son los metales más utilizados para aplicaciones biomédicas. La aleación más común, Ti6Al4V tiene desventajas de toxicidad y elevado modulo elástico. Para superarlas se usan cada vez más como aleantes el Niobio (Nb) y Molibdeno (Mo). Son elementos estabilizantes de fase β que tiene el módulo elástico más reducido y además son biocompatibles y poco tóxicos. El estaño (Sn) es un elemento neutro (no βestabilizante), no refractario que también es biocompatible y se utiliza mucho como aleante en biomateriales. La obtención de las aleaciones por el método pulvimetalurgico (PM) es una alternativa más económica al método convencional de colada, que además permite obtener formas de componentes difíciles de obtener por otras rutas. Sin embargo, las aleaciones obtenidas por PM presentan un problema de porosidad elevada que reduce la resistencia a compresión y corrosión. Se pretende reducir esta porosidad realizando tratamientos superficiales, uno de los cuales es la refusión con láser. En este tratamiento se funde una pequeña capa del material aportando calor con el rayo del láser a velocidad y potencia determinadas. Al solidificar se forma una capa superficial que puede mejorar las propiedades mecánicas de las piezas. En este trabajo se estudian algunas propiedades mecánicas y la microestructura de las muestras de 30x12x5 mm3 de aleaciones Ti-35Nb-2Sn y Ti-27Nb-8Mo obtenidas por PM después de la refusión superficial con cinco condiciones (potencia y velocidad del láser). En primer lugar, se analiza la porosidad y densidad relativa obtenidas por el método de Arquímedes. Se obtiene el módulo elástico utilizando la técnica de excitación por impulso. Se realiza el ensayo a flexión a cuatro puntos para obtener el módulo elástico a flexión, resistencia máxima y deformación. Se estudian las dimensiones de las zonas refundidas en las imágenes obtenidas mediante microscopia óptica. Mediante las imágenes de microscopia electrónica de barrido se analiza la microestructura tanto de los cordones de refusión como de las superficies refundidas y fracturas. Se evalúa la geometría de las superficies refundidas con un perfilómetro y finalmente se realiza el ensayo de nanoindentación de los cordones de refusión y la ZAC (zona afectada por el calor) para determinar la evolución de la dureza y el módulo de indentación a lo largo de ellos. Analizando los resultados de dichos ensayos podemos concluir que para las aleaciones en cuestión obtenidas por PM se consigue una mejora de algunas propiedades mecánicas superficiales gracias a la refusión superficial con el láser y se establecen algunas correlaciones entre los parámetros del láser y las mejoras. Sin embargo, habría que estudiar el comportamiento químico de las aleaciones para asegurar que no presenten problemas de corrosión. Este trabajo encuadra en los siguientes ODS (objetivos del desarrollo sostenible): -ODS 3, Salud y bienestar: ya que los implantes de las aleaciones estudiadas podrían ayudar a salvar las vidas, por ejemplo, de las víctimas de accidentes de tráfico, como lo propone la meta 3.6 - ODS 4, Educación de calidad: ya que el hecho de que la autora de este trabajo está realizando sus estudios demuestra el acceso igualitario de todos los hombres y las mujeres a una formación técnica, como lo propone la meta 4.3 -ODS 9, Industria, innovación e infraestructuras: ya que aporta a la investigación científica y mejora la capacidad tecnológica del sector industrial, como se propone en la meta 9.5, [CAT] Els aliatges de Titani (Ti) tenen una gran importància en nombroses indústries. En particular, són els metalls més utilitzats per a aplicacions biomèdiques. L'aliatge més comú, Ti6Al4V té desavantatges de toxicitat i elevat mòdul elàstic. Per superar-les usen cada vegada més com a aleants el Niobi (Nb) i Molibdè (Mo). Són elements estabilitzants de fase β que té el mòdul elàstic més reduït i a més són biocompatibles i poc tòxics. L'estany (Sn) és un element neutre (no β-estabilitzant), no refractari que també és biocompatible i s'utilitza molt com a aliant en biomaterials. La obtenció dels aliatges pel mètode pulvimetal·lúrgic (PM) és una alternativa més econòmica al mètode convencional de colada, que a més permet obtenir formes de components difícils d'obtenir per altres rutes. No obstant això, els aliatges obtinguts per PM presenten un problema de porositat elevada que redueix la resistència a compressió i corrosió. Es pretén reduir aquesta porositat fent tractaments superficials, un dels quals és la refusió amb làser. En aquest tractament es fon una petita capa del material aportant calor amb el raig del làser a velocitat i potència determinades. En solidificar es forma una capa superficial que pot millorar les propietats mecàniques de les peces. En aquest treball s'estudien algunes propietats mecàniques i la microestructura de les mostres de 30x12x5 mm3 d'aliatges Ti-35Nb-2Sn i Ti-27Nb-8Mo obtingudes per PM després de la refusió superficial amb cinc condicions (potència i velocitat del làser). A primer lloc, s'analitza la porositat i la densitat relativa obtingudes pel mètode d'Arquimedes. S'obté el mòdul elàstic utilitzant la tècnica d'excitació per impuls. Es realitza l'assaig a flexió a quatre punts per obtenir el mòdul elàstic a flexió, resistencia màxima i deformació. S'estudien les dimensions de les zones refoses a les imatges obtingudes mitjançant microscòpia òptica. Mitjançant les imatges de microscòpia electrònica d'escombrada s'analitza la microestructura tant dels cordons de refusió com de les superfícies refoses i les seues fractures. S'avalua la geometria de les superfícies refoses amb un perfilòmetre i finalment es realitza el assaig de nanoindentació dels cordons de refusió i la ZAC (zona afectada per la calor) per determinar l'evolució de la duresa i el mòdul d'indentació al llarg d'ells. Analitzant els resultats d'aquests assaigs podem concloure que per els aliatges en qüestió obtinguts per PM s'aconsegueix una millora de algunes propietats mecàniques superficials gràcies a la refusió superficial amb el làser i s'estableixen algunes correlacions entre els paràmetres del làser i les millores. No obstant això, caldria estudiar el comportament químic dels aliatges per assegurar que no presenten problemes de corrosió. Aquest treball s'enquadra en els següents ODS (objectius del desenvolupament sostenible): -ODS 3, Salut i benestar: ja que els implants dels aliatges estudiades podrien ajudar a salvar les vides, per exemple, de les víctimes d'accidents de trànsit, com ho proposa la meta 3.6. - ODS 4, Educació de qualitat: ja que el fet que l'autora de aquest treball està fent els estudis demostra l'accés igualitari de tots els homes i les dones a una formación tècnica, com ho proposa la meta 4.3 -ODS 9, Indústria, innovació i infraestructures: ja que aporta resultats a la investigació científica i millora la capacitat tecnològica del sector industrial, com es proposa a la meta 9.5., [EN] The Titanium (Ti) alloys are important for many industries because of their unique properties. In particular, they are the most used metals for biomedical applications. The most common alloy, Ti6Al4V, has the disadvantages of toxicity and high elastic modulus. In order to overcome these disadvantages, the Nb (Niobium) and Mo (Molybdenum) are used as alloying elements in the recent years. They are stabilizing elements of the β phase, the one that offers the lowest elastic modulus. The tin (Sn) is a neutral element (not β-stabilizing) and non-refractory, which also presents great biocompatibility and is commonly used in biomaterials. The powder metallurgy (PM) is a cheaper alternative method of alloy fabrication which also allows creating components with shapes that are hard to achieve by other methods. On the other hand, the components created by PM have the problem of high porosity which leads to poor compression and corrosion resistance. This porosity can be reduced by applying superficial treatments. One of them is laser surface modification, in which a small layer of the material is melted with the laser beam with given power and speed. After solidification, a layer with improved mechanical properties is formed. In this work, some of mechanical properties and microstructure of Ti-35Nb-2Sn and Ti27Nb-8Mo alloys, obtained by PM and treated with laser, are studied. The samples of alloys of 30x12x5 mm3 and five laser conditions (sets of power and speed of the laser) were used. In the first place, the porosity and density obtained with the Archimedes method are analyzed. The elastic modulus is obtained using the pulse excitation technique. The, the four-point flexure test is performed to determine the elastic flexural modulus, resistance and deformation. The dimensions of the remelted zones are studied using the optical microscopy and with electron microscopy images are used to analyze the remelted surfaces as well as the fractures. To study the geometry of the surface, perfilometry is used. And finally, nanoindentation tests of the remelted zones and HAZ (head affected zones) are performed to determine the evolution of the microhardness and nanoindentation modulus. Analyzing the results of the tests described above, the conclusion is, the laser surface modification improves some of the mechanical surface properties of the studied alloys obtained by PM. In addition, the correlations of these improvements with the laser conditions are established. However, the chemical analysis of the alloys should be performed to make sure they do not present significant corrosion problems. This work could be framed in the following SDG (sustainable development goals): -SDG 3, Good health and well-being: as the implants made of the studied alloys could save lives, for example, of the traffic accident victims, as the target 3.6 suggests. - SDG 4, Quality education: as the fact that the author of this work is carrying out her studies demonstrates the equal access opportunities to technical degrees for men and women, as it is stated in the target 4.3. -SDG 9, Industry, innovation and infrastructures: as it contributes to the scientific investigation and improves the technological capacity in the industrial sector, as it is is proposed in the target 9.5.

[ES] El grabado láser consiste en provocar, mediante un haz de luz alta energía, una oxidación controlada en la superficie de una pieza metálica. El empleo de sistemas de diseño y fabricación asistido por ordenador (CAD / CAM) permite generar geometrías y caracteres en la pieza a grabar. Este estudio se centrará en el grabado láser de piezas de titanio aleado Ti6Al4V ELI, siendo este un material de uso muy extendido en la industria biomédica. Durante la realización de este proyecto se estudia el proceso de grabado láser en piezas de Ti6Al4V ELI dentro de un proyecto de transferencia de producción de un proveedor externo a fabricación interna. Además, se contextualiza este proceso de grabado láser en un contexto de gestión de riesgos y un sistema de calidad mediante el uso de PFMEA y la validación estadística del proceso de grabado láser y los resultados que este produce en la pieza final. Se estudia, además, dos alternativas de parametrización y realización del proceso de grabado láser con el objetivo de obtener las mejores condiciones de grabado teniendo en cuenta todo el flujo de fabricación de las piezas. A estas piezas se realizan los análisis superficiales pertinentes y las inspecciones de acuerdo con los criterios de inspección alineados con el plano de la pieza final con el objetivo de conseguir unos parámetros óptimos de grabado láser, que permitan obtener un acabado negro intenso que no se delamine tras los procesos de limpieza y que tenga los mínimos efectos posibles en el paciente final., [CAT] El gravat làser consisteix en provocar, mitjançant un fes de llum d’alta energia, una oxidació controlada en la superfície d’una peça metàl·lica. La utilització de sistemes de disseny i fabricació per ordinador (CAD/CAM) permet generar geometries i caràcters en la peça a gravar. Este estudi es centrarà en el gravat làser de peces de titani aliat Ti6Al4V ELI, sent aquest un material d’us molt estès en l’industria biomèdica. Durant la realització d’aquest projecte s’estudia el procés de gravat làser en peces de Ti6Al4V ELI en un projecte de transferència de producció de un proveïdor extern a fabricació interna. A més, es contextualitza aquest procés de gravat làser en un context de gestió de riscs i un sistema de qualitat mitjançant l’ús d’un PFMEA i la validació estadística del procés de gravat làser i els resultats que aquest procés produeix en la peça final. S’estudia, a demés, dues alternatives de parametrització i realització de del procés de gravat làser amb l’objectiu d’obtenir les millors condicions de gravat tenint en compte tot el fluix de fabricació de les peces. Amb aquestes peces es realitzaran els anàlisis superficials necessaris i les inspeccions d’acord amb els criteris d’inspecció alineats amb el pla de la peça final amb l’objectiu d’obtenir uns paràmetres òptims per al gravat làser que permeten obtenir un acabat negre intens que no es del·lamine després dels procesos de neteja i que causi els mínims efectes possibles en el pacient final., [EN] The laser marking process consists in inducing, using a high energy beam of light, a controlled oxidation of a metallic part¿s surface. This process, combined with the use of computer assisted design and manufacturing systems (CAD/CAM), allows for the generation of geometries and alphanumerical symbols. This study will be centered around laser marking on alloyed titanium Ti6Al4V ELI parts, because of the widespread use of this material on the biomedical industry. During the realization of this project the laser marking process on Ti6Al4V parts isstudied in the context of a transfer project from an external supplier to internal manufacturing. This laser marking process is contextualized within a risk management and quality management system by using a PFMEA. The laser marking process will also be statistically validated and the results of this process in the part will be studied. With the goal of obtaining the best laser marking conditions and considering all the manufacturing flow, two different alternatives for parametrization will be studied. The parts surface will be analyzed, and the parts will be inspected according to the inspection criteria aligned with the parts drawing. This will be performed with the objective of obtaining the optimal laser marking parameters that will allow for the obtention of a clear black mark that will not delaminate after the cleaning process and that is harmless to the final patient

Titanium mini-implants are used as anchorage for orthodontic tooth movements. However, these implants present problems due to the infection of surrounding tissues. The aim of this work was to obtain a polyethylene glycol (PEG) layer by plasma in order to achieve a bacteriostatic surface. Titanium surfaces were activated by argon plasma and, after, by PEG plasma with different powers (100, 150 and 200 W) for 30 and 60 min. The roughness was determined by white light interferometer microscopy and the wettability was determined by the contact angle technique. Surface chemical compositions were characterized by X-ray photoelectron spectroscopy (XPS) and cytocompatibility and cell adhesion studies were performed with fibroblast (hFFs) and osteoblast (SAOS-2) cells. Bacterial cultures with Spectrococcus Sanguinis and Lactobacillus Salivarius were performed, and bacterial colonization was determined. The results showed that plasma treatments do not affect the roughness. Plasma makes the surfaces more hydrophilic by decreasing the contact angles from 64.2° for titanium to 5.2° for argon-activated titanium, with values ranging from 12° to 25° for the different PEG treatments. The plasma has two effects: the cleaning of the surface and the formation of the PEG layer. The biocompatibility results were, for all cases, higher than 80%. The polymerization treatment with PEG reduced the adhesion of hFFs from 7000 to 6000 and, for SAOS-2, from 14,000 to 6500, for pure titanium and those treated with PEG, respectively. Bacterial adhesion was also reduced from 600 to 300 CFU/mm2 for Spetrococcuns Sanguinis and from 10,000 to 900 CFU/mm2 for Lactobacillus Salivarius. The best bacteriostatic treatment corresponded to PEG at 100 W and 30 s. As a consequence, the PEG coating would significantly prevent the formation of bacterial biofilm on the surface of titanium mini-implants. info:eu-repo/semantics/publishedVersion

Reaction of [TiCp*Cl-3] (Cp*=eta(5)-C5Me5) with one equivalent of magnesium in tetrahydrofuran at room temperature affords the paramagnetic trinuclear complex [{TiCp*(mu-Cl)}(3)(mu(3)-Cl)], which reacts with dinitrogen under ambient conditions to give the diamagnetic derivative [{TiCp*(mu-Cl)}(3)(mu(3)-eta(1) : eta(2) : eta(2)-N-2)] and the titanium(III) dimer [{TiCp*Cl(mu-Cl)}(2)]. The structure of the trinuclear mixed-valence complexes has been studied by experimental and theoretical methods and the latter compound represents the first well-defined example of the mu(3)-eta(1) : eta(2) : eta(2) coordination mode of the dinitrogen molecule. The reaction of [{TiCp*(mu-Cl)}(3)(mu(3)-eta(1) : eta(2) : eta(2)-N-2)] with excess HCl in tetrahydrofuran results in clean NH4Cl formation with regeneration of the starting material [TiCp*Cl-3]. Therefore, a cyclic ammonia synthesis under ambient conditions can be envisioned by alternating N-2/HCl atmospheres in a [TiCp*Cl-3]/Mg(excess) reaction mixture in tetrahydrofuran., Ministerio de Ciencia, Innovación y Universidades, Universidad de Alcalá, Spanish Structures of Excellence María de Maeztu

The influence of the surface topography of dental implants has been studied to optimize titanium surfaces in order to improve osseointegration. Different techniques can be used to obtain rough titanium, however, their effect on wettability, surface energy, as well as bacterial and cell adhesion and differentiation has not been studied deeply. Two-hundred disks made of grade 4 titanium were subjected to different treatments: machined titanium (MACH), acid-attacked titanium (AE), titanium sprayed with abrasive alumina particles under pressure (GBLAST), and titanium that has been treated with GBLAST and then subjected to AE (GBLAST + AE). The roughness of the different treatments was determined by confocal microscopy, and the wettability was determined by the sessile drop technique; then, the surface energy of each treatment was calculated. Osteoblast-like cells (SaOs-2) were cultured, and alkaline phosphatase was determined using a colorimetric test. Likewise, bacterial strains S. gordonii, S. oralis, A. viscosus, and E. faecalis were cultured, and proliferation on the different surfaces was determined. It could be observed that the roughness of the GBLAST and GBLAS + AE was higher, at 1.99 and 2.13 μm of Ra, with respect to the AE and MACH samples, which were 0.35 and 0.20 μm, respectively. The abrasive treated surfaces showed lower hydrophilicity but lower surface energy. Significant differences could be seen at 21 days between SaOS-2 osteoblastic cell adhesion for the blasted ones and higher osteocalcin levels. However, no significant differences in terms of bacterial proliferation were observed between the four surfaces studied, demonstrating the insensitivity of bacteria to topography. These results may help in the search for the best topographies for osteoblast behavior and for the inhibition of bacterial colonization. info:eu-repo/semantics/publishedVersion

Osseointegration capacity and good mechanical behavior are key to the success of the dental implant. In many investigations, comparisons of properties are made using different dental implant designs and therefore the results can be influenced by the macrodesign of the dental implant. In this work, studies were carried out with the same dental implant model using different roughness and different materials—commercially pure titanium (grade 4) and zirconia. For this purpose, 80 smooth passivated titanium (Ti), 80 smooth zirconia (ZrO2), and 80 rough passivated titanium (Ti-R) dental implants were used. The samples were characterized by their roughness, wettability, surface energy, residual stresses, and fatigue behavior. The implants were implanted in minipigs for 4 and 12 weeks. The animals were sacrificed, and histological studies were carried out to determine the osseointegration parameters for each of the implantation times. Ti and ZrO2 dental implants have very similar wettability and surface energy properties. However, the roughness causes a decrease in the hydrophilic character and a decrease of the total surface energy and especially the dispersive component, while the polar component is higher. Due to the compressive residual stresses of alumina sandblasting, the rough dental implant has the best fatigue behavior, followed by Ti and due to the lack of toughness and rapid crack propagation the ZrO2 implants have the worst fatigue behavior. The bone index contact (BIC) values for 4 weeks were around 25% for Ti, 32% for ZrO2, and 45% for Ti-R. After 12 weeks the Ti dental implants increased to 42%, for Ti, 43% for ZrO2, and an important increase to 76% was observed for Ti-R implants. In vivo results showed that the key factor that improves osseointegration is roughness. There was no significant difference between ZrO2 and Ti implants without sandblasting. info:eu-repo/semantics/publishedVersion

Background: The objective of this study was to evaluate the accumulation of ions in blood and organs caused by Ti metal particles in a mandibular defect in rats, together with a description of the local reaction of oral tissues to these titanium alloy debris. Methods: Twenty Sprague-Dawley rats were randomly distributed into three groups: an experimental group with a mandibular bone defect filled with metallic debris obtained by implantoplasty; a positive control group; and a negative control group. Thirty days after surgery, the rats were euthanized and perilesional tissue surrounding the mandibular defect was removed, together with the lungs, spleen, liver and brain. Two blood samples were collected: immediately before surgery and before euthanasia. The perilesional tissue was histologically analyzed using hematoxylin-eosin staining, and titanium, aluminum and vanadium ion concentrations in blood and organs were measured by TQ-ICP-MS. Descriptive and bivariate analyses of the data were performed. Results: All rats with implanted metal debris showed metal particles and a bone fracture callus on the osseous defect. The metal particles were surrounded by a foreign body reaction characterized by the presence of histiocytes and multinucleated giant cells. The experimental group had a significant higher concentration of Ti ions in all studied organs except lung tissue (p < 0.05). In addition, there were more V ions in the brain in the experimental group (p = 0.008). Conclusions: Although further studies are required to confirm the clinical relevance of these results, Ti metal particles in the jaw might increase the concentration of metal ions in vital organs and induce a foreign body reaction. This article is protected by copyright. All rights reserved. Keywords: Ion release; Ti6Al4V; implantoplasty; metal particles; peri-implantitis; titanium.

A lack of primary stability and osteointegration in metallic implants may result in implant loosening and failure. Adding porosity to metallic implants reduces the stress shielding effect and improves implant performance, allowing the surrounding bone tissue to grow into the scaffold. However, a bioactive surface is needed to stimulate implant osteointegration and improve mechanical stability. In this study, porous titanium implants were produced via powder sintering to create different porous diameters and open interconnectivity. Two strategies were used to generate a bioactive surface on the metallic foams: (1) an inorganic alkali thermochemical treatment, (2) grafting a cell adhesive tripeptide (RGD). RGD peptides exhibit an affinity for integrins expressed by osteoblasts, and have been reported to improve osteoblast adhesion, whereas the thermochemical treatment is known to improve titanium implant osseointegration upon implantation. Bioactivated scaffolds and control samples were implanted into the tibiae of rabbits to analyze the effect of these two strategies in vivo regarding bone tissue regeneration through interconnected porosity. Histomorphometric evaluation was performed at 4 and 12 weeks after implantation. Bone-to-implant contact (BIC) and bone in-growth and on-growth were evaluated in different regions of interest (ROIs) inside and outside the implant. The results of this study show that after a long-term postoperative period, the RGD-coated samples presented higher quantification values of quantified newly formed bone tissue in the implant’s outer area. However, the total analyzed bone in-growth was observed to be slightly greater in the scaffolds treated with alkali thermochemical treatment. These results suggest that both strategies contribute to enhancing porous metallic implant stability and osteointegration, and a combination of both strategies might be worth pursuing. info:eu-repo/semantics/publishedVersion

[ES] En el presente trabajo se plantea realizar inicialmente un análisis del estado de arte sobre la evolución de la bicicleta según diferentes modalidades y usos, los componentes que la forman y materiales empleados, así como los procesos de fabricación. Con ello, se propone como objetivo principal del diseño, cálculo y selección de materiales para un cuadro de bicicleta de carretera a partir de los requerimientos funcionales determinados. En una primera fase, se plantea establecer una geometría básica sobre la que poder realizar la hipótesis de carga mediante el empleo del método de los elementos finitos que originaría un ciclista de forma estática y en movimiento. Esta etapa puede sufrir diferentes iteraciones hasta lograr optimizar la geometría del cuadro. A partir del análisis de fuerzas a las que el cuadro está sometido, se podrá en una segunda etapa estudiar los distintos materiales seleccionados con ayuda del software GRANTA CES Edupack. Se tendrá en cuenta también en esta fase, aspectos relacionados con los procesos de fabricación y acabado superficial. Finalmente, se propone un estudio económico en el que se incluyan los diferentes requisitos del proceso de diseño llevado a cabo., [CAT] En aquest treball es planteja realitzar inicialment una anàlisi de l'estat d'art sobre l'evolució de la bicicleta segons diferents modalitats i usos, els components que la formen i els materials emprats, així com els processos de fabricació. Amb això, es proposa com a objectiu principal del disseny, càlcul i selecció de materials per a un quadre de bicicleta de carretera a partir dels requeriments funcionals determinats. En una primera fase, es planteja establir una geometria bàsica sobre la qual poder fer la hipòtesi de càrrega mitjançant l'ús del mètode dels elements finits que originaria un ciclista de forma estàtica i en moviment. Aquesta etapa pot patir diferents iteracions fins aconseguir optimitzar la geometria del quadre. A partir de l'anàlisi de forces a què el quadre està sotmès, es podrà en una segona etapa estudiar els diferents materials seleccionats amb ajuda del programari GRANTA CES Edupack. Es tindrà en compte també en aquesta fase aspectes relacionats amb els processos de fabricació i acabat superficial. Finalment, es proposa un estudi econòmic en què s'incloguin els diferents requisits del procés de disseny dut a terme., [EN] In the present work, it is proposed to initially carry out an analysis of the state of the art on the evolution of the bicycle according to different modalities and uses, the components that form it and the materials used, as well as the manufacturing processes. With this, it is proposed as the main objective of the design, calculation and selection of materials for a road bicycle frame based on the determined functional requirements. In a first phase, it is proposed to establish a basic geometry on which to carry out the load hypothesis by using the finite element method that a static and moving cyclist would originate. This stage can undergo different iterations until the geometry of the frame is optimized. From the analysis of the forces to which the frame is subjected, it will be possible in a second stage to study the different materials selected with the help of the GRANTA CES Edupack software. In this phase, aspects related to manufacturing processes and surface finishing will also be taken into account. Finally, an economic study is proposed in which the different requirements of the process are included, both from the point of view of the material and the manufacturing process of a road bicycle frame.

The augmentation of the alveolar crest after the loss of one or several teeth can be carried out using different bone augmentation techniques. These techniques include bone distraction, ridge expansion, bone block grafts, etc. Guided bone regeneration is an alternative to increase the volume of the hard tissues for the subsequent placement of the implants in the optimal three-dimensional position. The objective of this paper is to show a case report of the use of customized titanium mesh for posterior vertical bone regeneration. Case report and Results: A 59-year-old woman comes to rehabilitate edentulous spaces with implants. After taking the anamnesis and the intra and extraoral exploration, a vertical and horizontal bone defect is observed in the third quadrant. After the radiological study with CBCT, a bone height of 6.04 mm to the inferior alveolar nerve and a width of the bone crest of 3.95 mm was observed. It was decided to carry out a regeneration with a preformed titanium mesh (Avinent®, Santpedor, Spain) and four microscrews (Avinent®, Santpedor, Spain). The flap was closed without tension. Regular check-ups were performed without complications. At 7 months, the mesh was removed and two osteoingrated implants (Avinent®, Santpedor, Spain) were placed with a torque greater than 45 N/cm and an ISQ of 82 and 57 N/cm, respectively. The bone gain obtained was 1.84 and 1.92 mm in width and 4.2 and 3.78 mm in height for positions 3.5 and 3.6. The newly formed bone, obtained by trephine, was well-structured and histologically indistinguishable from the previous bone. Conclusion: The use of a customized pre-formed titanium mesh together with the mixture of autologous bone and xenograft is a feasible and predictable technique for vertical bone regeneration.

[eng] This thesis consists in the development of a new methodology of α-alkylation of carbonyl compounds and its application to the synthesis of small molecules with therapeutic interest. In this context, the alkylation of carbonyl compounds is usually achieved by alkylation of nucleophilic metal enolates with alkyl halides through a SN2 substitution mechanism. This approach entails a limited scope in terms of alkylating agent since the alkyl halide should be activated enough to undergo such substitution. In this thesis, a radical alternative which uses titanium(IV) enolates is presented. In fact, titanium enolates are found in equilibrium between a nucleophilic species, the titanium(IV) enolate, and a biradical species, the titanium(III). This equilibrium is the result of a valence tautomerism that lies in an electron transfer from the ligand (the enolate) to the metal center (titanium), which is reduced to titanium(III). As a consequence of this redox process, the enolate becomes an open shell species with three electrons in the acyl moiety instead of four, which grants the enolate with radical reactivity. In chapter one, this reactivity is exploited to achieve the radical alkylation of titanium(IV) enolates from chiral N-acyl oxazolidinones with diacyl peroxides. When mixed with the enolate, these species break homolytically to give an acyloxy radical, which upon decarboxylation, generates an alkyl radical that recombines with the titanium enolate to give a single diastereomer of the alkylated product. The high reactivity of alkyl radicals permits us to perform the alkylation with deactivated primary and secondary alkyl groups, a transformation that is difficult to achieve by other established methodologies. A broad scope of primary and secondary diacyl peroxides including different functional groups such as unsaturations, phenyl or esters is described. In addition, the alkylation can be performed on a vast range of titanium enolates, which can also include such functionalities as well as an oxygen, nitrogen or chlorine in the α position. This methodology is finally applied to the straightforward synthesis of arundic acid. In chapter two, the total synthesis of umuravumbolide, a substituted pyrone extracted from a medicinal plant, is described. The synthesis includes the abovementioned alkylation of a titanium enolate derived from glycolic acid to furnish the stereocenter in the side chain. Other key steps are the formation of a Z double bond and an asymmetric allylation of a sensitive aldehyde intermediate. Chapter three describes an analogous alkylation procedure to that one investigated in the first chapter, only this time, tert-butyl peresters are used instead of diacyl peroxides. This change allows the alkylation of titanium enolates derived from chiral N-acyl oxazolidinones with secondary and even tertiary alkyl groups, a transformation that is rarely reported in the literature. A broad scope of secondary and tertiary peresters is described for this transformation. And similarly to chapter one, different titanium enolates including functional groups such as esters, unsaturations or heteroatoms can be used for such alkylation procedure. Finally, in chapter four other alkylating agents that are able to render an alkyl radical are investigated. However, the alkylation product is not obtained in any of the examples tested against titanium enolates. Therefore, the substitution of titanium for another metal that can render biradical enolates but at the same time can be used in catalytic amounts is attempted. For that, a screening of different metals in various oxidation states is performed. In this case, TEMPO is used to trap a putative biradical enolate., [cat] Aquesta tesi es basa en el desenvolupament d’una metodologia d’α-alquilació de compostos carbonílics i l’aplicació d’aquesta a la síntesis de petites molècules orgàniques d’interès terapèutic. La característica més rellevant d’aquesta nova metodologia és el seu mecanisme radicalari, que es manifesta gràcies a l’ús d’enolats de titani(IV). De fet, aquests enolats es troben en equilibri a través d’un procés de tautomeria de valència entre una espècie de caràcter nucleòfil, l’enolat de titani(IV), i una espècie biradicalaria, l’enolat de titani(III). En el primer capítol, s’estudia l’alquilació d’enolats de titani derivats de N-acil oxazolidinones quirals amb peròxids de diacil. L’escissió d’aquests últims dona lloc a un radical aciloxi que, després d’un procés de descarboxilació, forma un radical alquil que reacciona amb l’enolat de titani per donar lloc al producte d’alquilació com a únic diastereòmer. Aquest procediment permet l’alquilació amb un ampli ventall de peròxids de diacil que contenen grups d’alquil primaris i secundaris amb diversos grups funcionals, tals com dobles i triples enllaços, fenils o esters. A més a més, també permet alquilar diversos enolats amb funcionalitats semblants, fins i tot, amb oxigen, nitrogen i clor en posició alfa. Aquesta metodologia s’aplica a la síntesis directa de l’àcid arúndic. En el segon capítol, es duu a terme la síntesis total de la umuravumbolida, una pirona substituïda que s’extreu d’una planta medicinal. En aquesta síntesi es fa servir l’alquilació anteriorment descrita per formar l’estereocentre de la cadena lateral de la umuravumbolida. En el tercer capítol es desenvolupa una alquilació d’enolats de titani anàloga a la del primer capítol, aquest cop, però, emprant perèsters de tert-butil. Aquest canvi permet l’alquilació amb grups secundaris i terciaris, una transformació que normalment és difícil d’aconseguir. Com en el primer capítol, l’alquilació també permet l’ús de diferents enolats de titani amb funcionalitats diverses. Finalment, en el quart capítol es busquen altres agents alquilants que formin radicals alquil. No obstant, no s’aconsegueix l’alquilació de l’enolat de titani en cap dels casos. Per tant, es fa un canvi d’objectiu i es busca trobar un metall substitut del titani que també pugui formar enolats amb activitat radicalària però de manera catalítica.

Titanium dental meshes have a wide application in order to ensure the retention of calcium phosphate-based biomaterials to regenerate bone tissue. These meshes are temporary and must grow a soft tissue to prevent bacterial colonization and provide stability. In this work, we aimed to optimize the roughness of the meshes to obtain a good biological seal while maintaining a behavior that did not favor bacterial colonization. To this end, six types of surfaces were studied: machined as a control, polished, sandblasted with three different alumina sizes and sintered. The roughness, contact angles and biological behavior of the samples using fibroblast cultures at 7, 24 and 72 h were determined as well as cytotoxicity studies. Cultures of two very common bacterial strains in the oral cavity were also carried out: Streptococcus sanguinis and Lactobacillus salivarius. The results showed that the samples treated with alumina particles by sandblasting at 200 micrometers were the ones that performed best with fibroblasts and also with the number of bacterial colonies in both strains. According to the results, we see in this treatment a candidate for the surface treatment of dental meshes with an excellent performance. info:eu-repo/semantics/publishedVersion

The techniques used in oral implantology to remove bacterial biofilm from the surface of implants by machining the titanium surface (implantoplasty) or by placing rough dental implants through friction with the cortical bone generate a large release of particles. In this work, we performed a simulation of particle generation following clinical protocols. The particles were characterized for commercially pure titanium with particle sizes of 5, 10, 15, and 30 μm. The aim was to determine the effect of particle size and chemical composition of the implant on the immune response. For this purpose, their morphology and possible contamination were characterized by scanning electron microscopy and X-ray microanalysis. In addition, the granulometry, specific surface area, release of metal ions into the medium, and studies of cytocompatibility, gene expression, and cytokine release linked to the inflammatory process were studied. The release of ions for titanium particles showed levels below 800 ppb for all sizes. Smaller particle sizes showed less cytotoxicity, although particles of 15 μm presented higher levels of cytocompatibility. In addition, inflammatory markers (TNFα and Il-1β) were higher compared to larger titanium. Specifically, particles of 15 μm presented a lower proinflammatory and higher anti-inflammatory response as characterized by gene expression and cytokine release, compared to control or smaller particles. Therefore, in general, there is a greater tendency for smaller particles to produce greater toxicity and a greater proinflammatory response. info:eu-repo/semantics/publishedVersion

Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2021-2022. Director: Javier Fernández González. Tutora: Raisha Lorena García Cadme., Increased life expectancy leads to the increasing use of metallic prostheses. Titanium and its alloys are the most widely used materials for metallic prostheses thanks to their biocompatibility, but further work still necessary to improve bioactivity and reduce osseointegration problems. Developing nanostructured titanium dioxide (TiO2) coatings increases the biocompatibility of titanium prostheses. Using the electrolytic anodizing process, nanostructures can be achieved easily and economically. This project aims to optimize the voltage and anodizing time conditions to obtain titanium dioxide nanotubes on the surface of Ti-6Al-7Nb alloy, as well as to propose ideas for industrial implementation of the project. To this purpose, a market study, a project implementation plan and a technical and economic feasibility analysis were carried out. An electron microscope image processing method and a rigorous statistical analysis have been studied to obtain an average pore diameter quantify the effect of the studied variables. Potentials of 15, 30 and 60 volts and anodizing times of 15 and 30 minutes were studied. The effect of the concentration of fluoride ions and the type of cathode used in anodizing has also been studied. The optimum conditions for the smallest pore size we have found are anodizing at 15V and 15 minutes, with a grid cathode. With these conditions, an average pore diameter of 0,48 ± 0,05 μm was obtained.

Implantoplasty is a mechanical decontamination technique that consists of polishing the supra-osseous component of the dental implant with peri-implantitis. This technique releases metal particles in the form of metal swarf and dust into the peri-implant environment. In the present in vitro study, the following physicochemical characterization tests were carried out: specific surface area, granulometry, contact angle, crystalline structure, morphology, and ion release. Besides, cytotoxicity was in turn evaluated by determining the fibroblastic and osteoblastic cell viability. As a result, the metal debris obtained by implantoplasty presented an equivalent diameter value of 159 µm (range 6–1850 µm) and a specific surface area of 0.3 m2/g on average. The particle had a plate-like shape of different sizes. The release of vanadium ions in Hank’s solution at 37 °C showed no signs of stabilization and was greater than that of titanium and aluminum ions, which means that the alloy suffers from a degradation. The particles exhibited cytotoxic effects upon human osteoblastic and fibroblastic cells in the whole extract. In conclusion, metal debris released by implantoplasty showed different sizes, surface structures and shapes. Vanadium ion levels were higher than that those of the other metal ions, and cell viability assays showed that these particles produce a significant loss of cytocompatibility on osteoblasts and fibroblasts, which means that the main cells of the peri-implant tissues might be injured. info:eu-repo/semantics/publishedVersion

[ES] El titanio comercialmente puro (CP-Ti) proporciona una excelente resistencia a la corrosión y tiene un amplio abanico de aplicaciones siendo el Ti6Al4V la aleación más utilizada en el ámbito de la biomedicina. Sin embargo, a pesar de sus características y comportamiento a corrosión, el titanio y sus aleaciones tienen un elevado precio debido a su complicada extracción y procesamiento. De esta situación surgen las técnicas de manufactura por pulvimetalurgia que han ganado una aceptación considerable en la fabricación en grandes cantidades de otros metales ligeros como el aluminio. Estas técnicas pueden proveer una forma económica de procesar aleaciones de titanio. El desarrollo de aleaciones de titanio mediante pulvimetalurgia implicaría una gran oportunidad para expandir las aplicaciones de estas aleaciones en un gran número de industrias como automoción, aeroespacial y particularmente la biomédica. Aunque los estudios de la adición de estaño en titanio para obtener aleaciones mediante pulvimetalurgia han sido limitados es interesante estudiar el comportamiento de estas debido a su buena biocompatibilidad y a sus propiedades mecánicas en contraposición al Ti6Al4V ya que al utilizarlo para implantes en óseos se ha comprobado que se producía un desgaste considerable en el hueso. Para estudiar el comportamiento de estas aleaciones se han generado muestras de Ti-1Sn, Ti-2Sn y Ti-4Sn mediante técnicas de pulvimetalurgia convencionales y se han estudiado sus propiedades mecánicas mediante ensayos de flexión a cuatro puntos, microdureza y excitación por impulso. También se ha estudiado su microestructura mediante microscopía óptica, electrónica de barrido y EBSD además de sus propiedades químicas mediante ensayos de liberación de iones y corrosión., [CA] El titani comercialment pur (CP-Ti) proporciona una excel·lent resistència a la corrosió i té un ampli ventall d'aplicacions sent el Ti6Al4V l'aliatge més utilitzat en l'àmbit de la biomedicina. No obstant això, malgrat les seues característiques i comportament a corrosió, el titani i els seus aliatges tenen un elevat preu degut a la seua complicada extracció i processament. D'aquesta situació sorgeixen les tècniques de manufactura per pulvimetalurgia que han guanyat una acceptació considerable en la fabricació en grans quantitats d'altres metalls lleugers com l'alumini. Aquestes tècniques poden proveir una forma econòmica de processar aliatges de titani. El desenvolupament d'aliatges de titani mitjançant pulvimetalurgia implicaria una gran oportunitat per a expandir les aplicacions d'aquests aliatges en un gran nombre d'indústries com a automoció, aeroespacial i particularment la biomèdica. Encara que els estudis de l'addició d'estany en titani per a obtindre aliatges mitjançant pulvimetalurgia han sigut limitats és interessant estudiar el comportament d'aquestes a causa de la seua bona biocompatibilitat i a les seues propietats mecàniques en contraposició al Ti6Al4V ja que en utilitzar-lo per a implants en ossis s'ha comprovat que es produïa un desgast considerable en l'os. Per a estudiar el comportament d'aquests aliatges s'han generat mostres de Ti-1Sn, Ti-2Sn i Ti-4Sn mitjançant tècniques de pulvimetalurgia convencionals i s'han estudiat les seues propietats mecàniques mitjançant assajos de flexió a quatre punts, microduresa i excitació per impuls. També s'ha estudiat la seua microestructura mitjançant microscòpia òptica, electrònica d'escombratge i EBSD a més de les seues propietats químiques mitjançant assajos d'alliberament d'ions i corrosió., [EN] Commercially pure titanium (CP-Ti) provides excellent corrosion resistance and has a wide range of applications, with Ti6Al4V being the most widely used alloy in the field of biomedicine. However, despite their characteristics and corrosion behavior, titanium and its alloys have a high price due to their complicated extraction and processing. Because of this situation, powder metallurgy manufacturing techniques arose and have gained considerable acceptance in the large quantity manufacturing of other light metals such as aluminum. These techniques can provide an inexpensive way to process titanium alloys. The development of titanium alloys by powder metallurgy would imply a great opportunity to expand the applications of these alloys in many industries such as automotive, aerospace and particularly biomedical. Although the studies of the addition of tin in titanium to obtain alloys by powder metallurgy have been limited, it is interesting to study their behavior due to their good biocompatibility and their mechanical properties in contrast to Ti6Al4V since, when used for implants in bone, it has been proven that there was considerable wear on the bone. To study the behavior of these alloys, samples of Ti-1Sn, Ti-2Sn and Ti-4Sn have been generated using conventional powder metallurgy techniques and their mechanical properties have been studied using four-point bending, microhardness and impulse excitation tests. Its microstructure has also been studied using optical, scanning electron and EBSD microscopy, as well as its chemical properties through ion release and corrosion tests.

The performance and properties of Titanium (Ti) and its alloys can be fully exploited for biomedical applications such as orthopedic and dental implants, when porous structures are used. Such Ti structures can matched the bone mechanical properties, providing a solution to the stress-shielding effect problem and facilitating implant biointegration. Powder metallurgy (PM) combined with space holder (SH) technology is an appealing process to produce porous implants. This article briefly discusses the suitability of the PM with SH technology to produce porous structures from the perspectives of both design and manufacture for the production of medical devices.

Low-valent titanium species were prepared by reaction of [TiCp*X3] (Cp* = eta5-C5Me5; X = Cl, Br, Me) with LiEH4 (E = Al, B) or BH3(thf), and their structures elucidated by experimental and theoretical methods. The treatment of trihalides [TiCp*X3] with LiAlH4 in ethereal solvents (L) leads to the hydride-bridged heterometallic complexes [{TiCp*(mu-H)}2{(mu-H)2AlX(L)}2] (L = thf, X = Cl, Br; L = OEt2, X = Cl). Density functional theory (DFT) calculations for those compounds reveal an open-shell singlet ground state with a Ti-Ti bond and can be described as titanium(II) species. The theoretical analyses also show strong interactions between the Ti-Ti bond and the empty s orbitals of the Al atom of the AlH2XL fragments, which behave as sigma-accepting (Z-type) ligands. Analogous reactions of [TiCp*X3] with LiBH4 (2 and 3 equiv) in tetrahydrofuran at room temperature and at 85 ºC lead to the titanium(III) compounds [{TiCp*(BH4)(mu-X)}2] (X = Cl, Br) and [{TiCp*(BH4)(mu-BH4)}2], respectively. The treatment of [TiCp*Me3] with 4 and 5 equiv of BH3(thf) produces the diamagnetic [{TiCp*(BH3Me)}2(mu-B2H6)] and paramagnetic [{TiCp*(mu-B2H6)}2] complexes, respectively., Ministerio de Ciencia, Innovación y Universidades, Universidad de Alcalá

The lack of bioactivity of titanium (Ti) is one of the main drawbacks for its application in biomedical implants since it can considerable reduce its osseointegration capacities. One strategy to overcome this limitation is the coating of Ti with hydroxyapatite (HA), which presents similar chemical composition than bone. Nonetheless, most of the strategies currently used generate a non-stable coating and may produce the formation of amorphous phases when high temperatures are used. Herein, we proposed to generate a Ti-HA composite coating on Ti surface to improve the stability of the bioactive coating. The coating was produced by cold gas spraying, which uses relatively low temperatures, and compared to a Ti coating. The coating was thoroughly characterized in terms of morphology, roughness, porosity and phase composition. In addition, the coating was mechanically characterized using a tensile loading machine. Finally, biological response was evaluated after seeding SaOS-2 osteoblasts and measuring cell adhesion, proliferation and differentiation. The novel Ti-HA coating presented high porosity and high adhesion and bond strengths. No change in HA phases was observed after coating formation. Moreover, osteoblast-like cells adhered, proliferated and differentiated on Ti-HA coated surfaces suggesting that the novel coating might be a good candidate for biomedical applications. info:eu-repo/semantics/acceptedVersion

International audience; This paper is an experimental research about the mechanical effects on Ti-6Al-4V surfaces treated with an ultrasonic vibration-assisted ball burnishing process. Its aim is to define the process parameters to achieve the best surface integrity on the target workpiece, as well as identifying the effects caused by the introduction of vibrations as a means of assistance. A Taguchi orthogonal array including five factors (preload, number of passes, feed velocity, strategy and original surface texture) was applied to perform the process on ball-end milled surfaces. A comprehensive analysis of the effects was performed, by considering in depth three different facets of surface integrity, namely, topology, residual stress and hardness. Hence the extensive result datasets presented in this paper, which deliver an exhaustive description of the process effects by combining a triple approach in the results analysis section. The effect of vibrations is proved positive to enhance the texture as long as the original surface is not characterized by Sq >2 μm. Furthermore, only the preload and number of passes influence the results. In terms of residual stress, all parameters are influential in the results, especially the burnishing strategy, through which a specific direction can be reinforced. Finally, the burnishing operation proves to modify the hardness of deep layers down to 0.5 mm, applying the vibration-assisted process. The main conclusion derived from these works is a technical recommendation to treat the Ti-6Al-4 V surface through the process, aiming to find a balanced comprehensive surface integrity enhancement.

One of the biggest challenges in the biocompatibility of implantable metals is the prevention of the stress shielding effect, which is related to the coupling of the bone-metal mechanical properties. This stress shielding phenomenon provokes bone resorption and the consequent adverse effects on prosthesis fixation. However, it can be inhibited by adapting the stiffness of the implant material. Since the use of titanium (Ti) porous structures is a great alternative not only to inhibit this effect but also to improve the osteointegration of orthopedic and dental implants, a brief description of the techniques used for their manufacturing and a review of the current commercialized implants produced from porous Ti assemblies are compiled in this work. As powder metallurgy (PM) with space holder (SH) is a powerful technology used to produce porous Ti structures, it is here discussed its potential for the fabrication of medical devices from the perspectives of both design and manufacture. The most important parameters of the technique such as the size and shape of the initial metallic particles, the SH and binder type of materials, the compaction pressure of the green form, and in the sintering stage, the temperature, atmosphere, and time are reviewed according to the bibliography reported. Furthermore, the importance of the porosity and its types together with the influence of the mentioned parameters in the final porosity and, consequently, in the ultimate mechanical properties of the structure are discussed. Finally, a few examples of the PM-SH application for the manufacturing of orthopedic implants are presented.

The surface modification by the formation of apatitic compounds, such as hydroxyapatite, improves biological fixation implants at an early stage after implantation. The structure, which is identical to mineral content of human bone, has the potential to be osteoinductive and/or osteoconductive materials. These calcium phosphates provoke the action of the cell signals that interact with the surface after implantation in order to quickly regenerate bone in contact with dental implants with mineral coating. A new generation of calcium phosphate coatings applied on the titanium surfaces of dental implants using laser, plasma-sprayed, laser-ablation, or electrochemical deposition processes produces that response. However, these modifications produce failures and bad responses in long-term behavior. Calcium phosphates films result in heterogeneous degradation due to the lack of crystallinity of the phosphates with a fast dissolution; conversely, the film presents cracks, which produce fractures in the coating. New thermochemical treatments have been developed to obtain biomimetic surfaces with calcium phosphate compounds that overcome the aforementioned problems. Among them, the chemical modification using biomineralization treatments has been extended to other materials, including composites, bioceramics, biopolymers, peptides, organic molecules, and other metallic materials, showing the potential for growing a calcium phosphate layer under biomimetic conditions. Ramón y Cajal Beca a C.M.-M. RYC-2015-18566 Cofinanciados por la UE a través de la Unión Europea Fondos de Desarrollo Regional

Featured Application In this paper, a fast, one-step method to prepare acrylate-based coatings on titanium through the atmospheric pressure plasma polymerization of HEMA is described. The coating shows lower surface bacterial adhesion and enhanced cell adhesion when compared with pristine titanium. Dental implants can fail due to various factors, in which bad tissue integration is believed to have a significant role. Specific properties of the implant surface, such as its chemistry and roughness, are of paramount importance to address specific cell responses, such as the adsorption of proteins, as well as the adhesion and differentiation of cells, which are suitable for biomaterial and tissue engineering. In this study, an acrylate-containing coating was produced on titanium surfaces through the atmospheric pressure plasma treatment of a liquid precursor, 2-hydroxyethyl methacrylate. A hydrophilic coating was obtained, showing retention of the monomer chemistry as assessed by FTIR analysis and XPS. Enhanced fibroblast adhesion and decreased Staphylococcus aureus and Escherichia coli adhesion were recorded, showing that this is a suitable method to produce biocompatible coatings with a reduced bacterial adhesion.

Titanium, thanks to its good mechanical properties and an excellent biocompatibility and osseointegration, is used in the manufacture of dental implants. Nevertheless, after insertion into the human body, these implants can cause some issues such as periimplantitis, an inflammatory reaction caused by a microbial biofilm, which leads to the progressive loss of the implant. Thus, the objective of this project is to carry out different surface treatments of titanium used in biomedical applications in order to study the influence of surface properties, especially roughness, on bacterial adhesion. First of all, the main surface treatments with their advantages, limitations and parameters to be controlled were discussed. In this project, three were carried out, namely 'Sandblasting', 'SLA (Sandblasting, Large-grit, Acid Etching)’ and 'Alkali treatment'. Before these treatments, the titanium discs were polished. At the end, nine different surfaces were produced. The samples were observed with a Scanning Electron Microscope (SEM) and characterised in terms of roughness and surface energy. The topography and surface roughness were studied with equipment using the Chromatic Confocal principle. In addition, the surface tension was calculated using the Fowkes' theory on a contact angle database, obtained thanks to three different probe liquids (water, diiodomethane and formamide). The bacterial adhesion on these surfaces was then studied. Furthermore, the bacteria were fixed and observed at the SEM. After analysing the results, a correlation between surface roughness and bacterial adhesion was noticed: the rougher the surface increases, the more bacteria adhere to it. Moreover, bacteria adhere mainly in grooves and holes in the case of rough surfaces. High roughness provides a larger surface for bacteria adhesion. Thereby, smooth surfaces are more difficult to colonize than rough surfaces. On the other hand, it has been shown that surfaces that have undergone an Alkali treatment are super-hydrophilic. El titanio, gracias a sus buenas propiedades mecánicas y a su excelente biocompatibilidad y osteointegración, se utiliza en la fabricación de implantes, principalmente dentales. No obstante, tras su inserción en el cuerpo humano, estos implantes pueden causar problemas como la peri-implantitis, una reacción inflamatoria causada por un biofilm microbiano que lleva a la pérdida progresiva del implante. Así, el objetivo de este proyecto es llevar a cabo diferentes tratamientos superficiales del titanio utilizados en aplicaciones biomédicas para estudiar la influencia de las propiedades superficiales, especialmente la rugosidad, en la adhesión bacteriana. En primer lugar, se discutieron los principales tratamientos de superficie con sus ventajas, desventajas y parámetros a controlar. En este proyecto, se llevaron a cabo tres tratamientos, a saber, ‘Sandblasting’, ‘SLA (Sandblasting, Large-grit, Acid Etching)’ y ‘Alkali treatment’. Antes de estos tratamientos, los discos de titanio han sido pulidos. Finalmente, se produjeron nueve superficies diferentes. Las muestras se observaron con un microscopio electrónico de barrido (MEB) y se caracterizaron en términos de rugosidad y energía superficial. La topografía y la rugosidad superficial se estudiaron con un equipo que utiliza la microscopía confocal cromática. Además, la tensión superficial se calculó utilizando la teoría de Fowkes sobre una base de datos de ángulos de contacto obtenida con tres líquidos diferentes (agua, diiodometano y formamida). Se estudió entonces la adhesión bacteriana en estas superficies. Asimismo, las bacterias fueron fijadas y observadas en el MEB. Tras el análisis de los resultados, se observó una correlación entre la rugosidad de la superficie y la adhesión de las bacterias: en efecto, cuanto más rugosa sea la superficie, más se adhieren las bacterias a ella. Adicionalmente, las bacterias se adhieren principalmente en las ranuras y agujeros en el caso de superficies rugosas. Una alta rugosidad presenta una mayor superficie para que las bacterias se adhieran. Por lo tanto, las superficies lisas son más difíciles de colonizar que las superficies rugosas. Por otro lado, se ha demostrado que las superficies que han sido sometidas a un ‘Alkali treatment’ son súper-hidrófilas. Incoming

Els implants poden fallar per diverses raons, inclosa la falta d’osteointegració, la fractura de l’implant o les infeccions, entre altres. A més, alguns estudis discuteixen si l’osteoporosi augmenta o no les taxes de fallida de l’implant. El titani està mancat de capacitat osteoinductora i per això s’està treballant amb implants recoberts amb biomolècules d’unió a integrines inspirades en la ECM. Mitjançant peptidomimètics sintètics basats en la seqüència RGD s’aconsegueix la discriminació entre les integrines d’interès, en aquest cas α5β1 o αvβ3, que son les que estan més expressades en els osteoblasts i son essencials per a moltes de les funcions fonamentals en el desenvolupament del teixit ossi. En aquest projecte s’avalua la taxa i la qualitat de l’osteointegració en teixit ossi osteoporòtic amb implants dentals de titani funcionalitzats implantats en models d’experimentació animal en un assaig in vivo. S’inclou, per tant, la preparació de les mostres, l’estudi histomorfomètric i histològic de l’os i l’anàlisi dels resultats a fi d’identificar si l’osteointegració en os osteoporòtic es veu afavorida en utilitzar implants biofuncionalitzats. Els resultats mostren que els implants recoberts amb peptidomimètics presenten un contacte os-implant (BIC) més alt i una resposta més robusta i madura que els implants sense modificacions superficials. Tots els implants, tot i tractar-se de teixit ossi osteoporòtic, presenten una bona osteointegració. Los implantes pueden fallar por varias razones, incluida la falta de osteointegración, la fractura del implante o las infecciones, entre otras. Además, algunos estudios discuten si la osteoporosis aumenta o no las tasas de fallo del implante. El titanio carece de capacidad osteoinductora y por ello se está trabajando con implantes recubiertos con biomoléculas de unión a integrinas inspiradas en la ECM. Mediante peptidomiméticos sintéticos basados en la secuencia RGD se logra la discriminación entre las integrinas de interés, en este caso α5β1 o αvβ3, que son las que están más expresadas en los osteoblastos y son esenciales para muchas de las funciones fundamentales en el desarrollo del tejido óseo. En este proyecto se evalúa la tasa y la calidad de la osteointegración en tejido óseo osteoporótico con implantes dentales de titanio funcionalizados implantados en modelos de experimentación animal en un ensayo in vivo. Se incluye, por tanto, la preparación de las muestras, el estudio histomorfométrico e histológico del hueso y el análisis de los resultados a fin de identificar si la osteointegración en hueso osteoporótico se ve favorecida al utilizar implantes biofuncionalizados. Los resultados muestran que los implantes recubiertos con peptidomiméticos presentan un contacto hueso-implante (BIC) más alto y una respuesta más robusta y madura que los implantes sin modificaciones superficiales. Todos los implantes, a pesar de tratarse de tejido óseo osteoporótico, presentan una buena osteointegración. Implants can fail due to several reasons, including lack of osseointegration, implant fracture, or infections, among others. Furthermore, some studies discuss whether or not osteoporosis increases implant failure rates. Titanium lacks osteoinductive capacity and therefore extensive research has focused on implants coated with integrin-binding biomolecules inspired by the ECM. By means of synthetic peptidomimetics based on the RGD sequence, discrimination between the integrins of interest is achieved, in this case α5β1 or αvβ3, which are those that are most expressed in osteoblasts and are essential for many of the fundamental functions in the development of bone tissue. This project evaluates the rate and quality of osseointegration in osteoporotic bone tissue with functionalized titanium dental implants implanted in experimental animal models in an in vivo assay. Therefore, the preparation of the samples, the histomorphometric and histological study of the bone and the analysis of the results are included in order to identify whether osseointegration in osteoporotic bone is favored when using biofunctional implants. The results show that implants coated with peptidomimetics present a higher bone to implant contact (BIC) and a more robust and mature response than implants without superficial modifications. All implants, despite being osteoporotic bone tissue, show good osseointegration.

Background Peri-implantitis is a biological complication that affects soft and hard tissues around dental implants. Implantoplasty (IP) polishes the exposed implant surface, to decontaminate it and make it less prone to bacterial colonization. This study investigates whether a higher clinical crown-to-implant-ratio (CIR) reduces implant fracture resistance and whether implants are more fracture-prone after IP in the presence of 50% of bone loss. Methods Forty-eight narrow platform (3.5 mm) 15 mm long titanium dental implants with a rough surface and hexagonal external connection were placed in standardized bone-like resin casts leaving 7.5 mm exposed. Half were selected for IP. The IP and control groups were each divided into 3 subgroups with different clinical CIRs (2:1, 2.5:1 and 3:1). The implant wall width measurements were calculated using the software ImageJ v.1.51 through the analysis of plain x-ray examination of all the samples using standardized mounts. A fracture test was performed and scanning electron microscopy was used to evaluate maximum compression force (Fmax) and implant fractures. Results IP significantly reduced the implant wall width (P max was significantly higher in the 2:1 subgroup (control = 1276.16 N ± 169.75; IP = 1211.70 N ± 281.64) compared with the 2.5:1 (control = 815.22 N ± 185.58, P P P P P = 0.037) of the Fmax between the controls and the IP implants. Most fractures were located in the platform area. Only 5 implants with IP of the 2:1 CIR subgroup had a different fracture location (4 fractures in the implant body and 1 in the prosthetic screw). Conclusions IP significantly reduces the fracture resistance of implants with a 2.5:1 CIR. The results also suggest that the CIR seems to be a more relevant variable when considering the resistance to fracture of implants, since significant reductions were observed when unfavorable CIR subgroups (2.5:1 and 3:1 CIR) were compared with the 2:1 CIR samples.

The use of individualized titanium meshes has been referred to in scientific literature since 2011. There are many advantages to its use, however, the main complications are related to early or late exposures. As some aspects such as its surface properties have been pointed out to influence the soft tissue response, this study was designed to compare the surface characteristics of three commercially available individualized titanium meshes between them and according to the manufacturer&rsquo, s specifications. The results from the scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and the contact profilometry measurements were analyzed and cross-checked. It was discovered that, the BoneEasy&rsquo, s post-processing superficial treatment was more refined, as it delivers the mesh with the lowest Ra value, 0.61 &plusmn, 0.14 &micro, m, due to the applied electropolishing. On the other hand, the Yxoss CBR&reg, mesh from ReOss&reg, was sandblasted, presenting an extremely rough surface with a Ra of 6.59 &plusmn, 0.76 &micro, m.

Infections related to dental implants are a common complication that can ultimately lead to implant failure, and thereby carries significant health and economic costs. In order to ward off these infections, this paper explores the immobilization of triethoxysilylpropyl succinic anhydride (TESPSA, TSP) silane onto dental implants, and the interaction of two distinct monospecies biofilms and an oral plaque with the coated titanium samples. To this end, titanium disks from prior machining were first activated by a NaOH treatment and further functionalized with TESPSA silane. A porous sodium titanate surface was observed by scanning electron microscopy and X-ray photoelectron spectroscopy analyses confirmed the presence of TESPSA on the titanium samples (8.4% for Ti&ndash, N-TSP). Furthermore, a lactate dehydrogenase assay concluded that TESPSA did not have a negative effect on the viability of human fibroblasts. Importantly, the in vitro effect of modified surfaces against Streptococcus sanguinis, Lactobacillus salivarius and oral plaque were studied using a viable bacterial adhesion assay. A significant reduction was achieved in all cases but, as expected, with different effectiveness against simple mono-species biofilm (ratio dead/live of 0.4) and complete oral biofilm (ratio dead/live of 0.6). Nevertheless, this approach holds a great potential to provide dental implants with antimicrobial properties.

A new bis-hydroxyphenylpyrazolyl ligand, H4L, allows isolating and structurally characterizing vanadyl and titanyl dinuclear complexes (Bu4N)2[(MO)2(HL)2] (M = V, Ti). The weak dipolar coupling and relatively short quantum coherence of the divanadyl anions are optimal for a 2-qubit molecular architecture proposed to implement electron-mediated nuclear quantum simulations., This research was supported by Spanish MINECO (CTQ2015-68370-P, PGC2018-098630-B-I00, MAT2017-86826-R, CTQ2015-64486-R), the Aragón government (E31_17R) and EU quantERA (SUMO, PCI2018-093106, PCI2018-093116), and used resources of the ALBA synchrotron and of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DEAC02-05CH11231. G. A. thanks the Generalitat de Catalunya for the prize ICREA Academia 2018.

Through the years, the medicine has been modernized to reach today a complex science complying diagnosis, treatments and prevention of illness. This project is focused on the orthopedic surgery and more particularly on medical implants. Medical implants are medical devices which are incorporated in the human body in order to support or replace a missing biological structure. The human body is fragile, and it is necessary to pay attention to the biocompatibility of the medical implants in order to avoid contamination or poisoning. This is why medical implants are mostly made, nowadays, in biocompatible materials such as ceramics, polymers or specific metal alloys as titanium alloys or Nickel alloys. These materials present good corrosion resistance or even are completely inert towards the human body. This project will be focused on titanium orthopedic implants. Titanium and its alloys present interesting properties as a high strength to density ratio, a good corrosion resistance due to the combination of the different surface-formed oxide layers and offer an excellent biocompatibility. This unique combination of properties makes them ideal materials for medical implants. However, titanium implants present issues regarding long-term performances due to a mismatch in mechanical properties between the implant and natural bone. These differences can enhance stress shielding effect. To avoid this mismatch, the solution is to adjust the mechanical properties of titanium so that they are as similar as possible to those of bone. This is achieved by the introduction of a sufficient amount of porosity. Indeed, by controlling the porosity, it is possible to tailor the mechanical properties of a solid material. In order to confer a superior bone-bonding property to titanium implants, attempts have been made to coat their surfaces with a thin layer of bone-bonding ceramic, such assodium titanate, by the means of chemical and heat treatments To avoid infection, caused by the introduction of a foreign body in human body, silver ions, known for their antibacterial activity, may be incorporated to the medical implant. Beside silver ions, Gallium ions also present good antibacterial activity but they're mostly known for their impact on bone resorption. The aim of this study is to produce comparative studies of corrosion resistance with different samples of titanium implants. Will be studied the impact of the heat treatment and the introduction of the antibacterial ions on the electrochemical behavior. Incoming

The purpose of this study is to assess the use of grade V titanium mini transitional implants (MTIs) immediately loaded by a temporary overdenture. For this, a histomorphometric analysis of the bone area fraction occupancy (BAFO) was performed by backscattered scanning electron microscopy (BS-SEM). Four female patients were submitted to surgery in which two MTIs were installed and immediately loaded with a temporary acrylic prosthesis. During the same surgery, two regular diameter implants were placed inside the bone and maintained without mechanical load. After 8 months, the MTIs were extracted using a trephine and processed for ultrastructural bone analysis by BS-SEM, and the regular-diameter implants were loaded with an overdenture device. A total of 243 BAFOs of MTIs were analyzed, of which 94 were mainly filled with cortical bone, while 149 were mainly filled with trabecular bone. Bone tissue analysis considering the total BAFOs with calcified tissues showed 72.13% lamellar bone, 26.04% woven bone, and 1.82% chondroid bone without significant differences between the samples. This study revealed that grade V titanium used in immediately loaded MTI was successfully osseointegrated by a mature and vascularized bone tissue as assessed from the BAFO.

Titanium dental implants are widely used for the replacement of damaged teeth. However, bacterial infections at the interface between soft tissues and the implant can impair the functionality of the device and lead to failure. In this work, the preparation of an antifouling coating of polyethylene glycol (PEG) on titanium by pulsed electrodeposition was investigated in order to reduce Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) adhesion while maintaining human fibroblast adhesion. Different pulsed conditions were prepared and characterized by contact angle, Focused Ion Beam (FIB), Fourier Transformed Infrared Spectroscopy in the Attenuated Total Reflectance mode (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). XPS tested fibronectin adsorption. S. aureus, E. coli and human fibroblast adhesion was tested in vitro in both mono and co-culture settings. Physicochemical characterization proved useful for confirming the presence of PEG and evaluating the efficiency of the coating methods. Fibronectin adsorption decreased for all of the conditions, but an adsorption of 20% when compared to titanium was maintained, which supported fibroblast adhesion on the surfaces. In contrast, S. aureus and E. coli attachment on coated surfaces decreased up to 90% vs. control titanium. Co-culture studies with the two bacterial strains and human fibroblasts showed the efficacy of the coatings to allow for eukaryotic cell adhesion, even in the presence of pre-adhered bacteria.

Two-pieces dental implants must provide stability of the implant-abutment-interface. The connection type and platform diameter could influence the biomechanical resistance and stress distribution. This study aims to evaluate the fatigue for different types of connections, external and internal, and different platform diameters. Three implant designs with the same length were used: (a) external hexagon/narrow platform, (b) internal double hexagon/narrow platform, (c) internal octagon/regular platform. A fatigue test was developed to establish the number of cycles needed before fracture. A 30&ordm, oblique load with a sinusoidal function of fatigue at a frequency of 15 Hz and 10% stress variation was applied to each system. The fatigue load limit (FLL) for design (a) was 190N, being the nominal-curvature-moment (NCM) = 1.045, FLL = 150 N, with a NCM = 0.825 for (b), and FLL = 325 N, with a NCM = 1.788 for (c). The platform diameter affects the FLL, obtaining lower FLL on a narrow platform. The connection type interferes with the implant walls&rsquo, width, especially in narrow implants, making internal connections more unstable at this level. Long-term clinical studies to assess the restoration&rsquo, s success rate and survival are mandatory.

La esperanza de vida del ser humano ha aumentado considerablemente a lo largo de los años y esto requiere del aumento en la durabilidad de los materiales implantables con el fin de sustituirlos el menor número de veces posibles a lo largo de la vida del individuo. Esto motiva una línea de investigación científica basada en el proceso de recubrir el titanio utilizado para prótesis de cadera e implantes dentales con hidroxiapatita, el material que forma la parte mineral del hueso. En esta línea se basa el siguiente TFG con el objetivo de modificar superficialmente una lámina de Ti6Al-7Nb con el fin de inducir rugosidad sobre la misma. Esta modificación superficial se lleva a cabo mediante dos técnicas diferentes, una técnica mecánica (desbaste) y otra térmica (ablación láser). Posteriormente, se recubre dicha superficie mediante la tecnología de deposición térmica por plasma atmosférico y posteriormente se caracteriza microestructuralmente y se ensaya el conjunto recubrimiento/sustrato con el fin de conocer qué sustrato proporciona una mayor resistencia a la adherencia. Este proceso permite llegar a la conclusión, de que es necesaria una rugosidad de alrededor de 60 µm para poder conseguir unos resultados aceptables. L'esperança de vida de l'ésser humà ha augmentat considerablement al llarg dels anys i això requereix de l'augment en la durabilitat dels materials implantables amb la finalitat de substituir-los el menor nombre de vegades possibles al llarg de la vida de l'individu. Això motiva una línia de recerca científica basada en el procés de recobrir el titani utilitzat per a pròtesi de maluc i implants dentals amb hidroxiapatita, el material que forma la part mineral de l'os. En aquesta línia es basa el següent TFG amb l'objectiu de modificar superficialment una làmina de Ti6Al-*7Nb amb la finalitat d'induir rugositat sobre aquesta. Aquesta modificació superficial es duu a terme mitjançant dues tècniques diferents, una tècnica mecànica (desbastament) i una altra tèrmica (ablació làser). Posteriorment, es recobreix aquesta superfície mitjançant la tecnologia de deposició tèrmica per plasma atmosfèric i posteriorment es caracteritza microestructuralment i s'assaja el conjunt recobriment/substrat amb la finalitat de conèixer quin substrat proporciona una major resistència a l'adherència. Aquest procés permet arribar a la conclusió, que és necessària una rugositat al voltant de 60 µm per a poder aconseguir uns resultats acceptables. Human life expectancy has increased considerably over the years and this requires an increase in the durability of implantable materials in order to replace them as few times as possible throughout the individual's life. This motivates a line of scientific research based on the process of coating the titanium used for hip prostheses and dental implants with hydroxyapatite, the material that forms the mineral part of bone. The following TFG is based on this line with the aim of superficially modifying a Ti-6Al-7Nb sheet in order to induce roughness on it. This surface modification is carried out using two different techniques, a mechanical technique (grinding) and a thermal technique (laser ablation). Subsequently, said surface is coated using atmospheric plasma thermal deposition technology and subsequently it is microstructurally characterized and the coating/substrate assembly is tested in order to know which substrate provides greater resistance to adhesion. This process allows us to reach the conclusion that a roughness of around 60 µm is necessary to achieve acceptable results.

Passivation of titanium alloy dental meshes cleans their surface and forms a thin layer of protective oxide (TiO2) on the surface of the material to improve resistance to corrosion and prevent release of ions to the physiological environment. The most common chemical agent for the passivation process of titanium meshes is hydrochloric acid (HCl). In this work, we introduce the use of Piranha solution (H2SO4 and H2O2) as a passivating and bactericidal agent for metallic dental meshes. Meshes of grade 5 titanium alloy (Ti6Al4V) were tested after different treatments: as-received control (Ctr), passivated by HCl, and passivated by Piranha solution. Physical-chemical characterization of all treated surfaces was carried out by scanning electron microscopy (SEM), confocal microscopy and sessile drop goniometry to assess meshes’ topography, elemental composition, roughness, wettability and surface free energy, that is, relevant properties with potential effects for the biological response of the material. Moreover, open circuit potential and potentiodynamic tests were carried out to evaluate the corrosion behavior of the differently-treated meshes under physiological conditions. Ion release tests were conducted using Inductively Coupled Plasma mass spectrometry (ICP-MS). The antibacterial activity by prevention of bacterial adhesion tests on the meshes was performed for two different bacterial strains, Pseudomonas aeruginosa (Gram-) and Streptococcus sanguinis (Gram+). Additionally, a bacterial viability study was performed with the LIVE/DEAD test. We complemented the antibacterial study by counting cells attached to the surface of the meshes visualized by SEM. Our results showed that the passivation of titanium meshes with Piranha solution improved their hydrophilicity and conferred a notably higher bactericidal activity in comparison with the meshes passivated with HCl. This unique response can be attributed to differences in the obtained nanotextures of the TiO2 layer. However, Piranha solution treatment decreased electrochemical stability and increased ion release as a result of the porous coating formed on the treated surfaces, which can compromise their corrosion resistance. Framed by the limitations of this work, we conclude that using Piranha solution is a viable alternative method for passivating titanium dental meshes with beneficial antibacterial properties that merits further validation for its translation as a treatment applied to clinically-used meshes. info:eu-repo/semantics/publishedVersion

Commercially pure grade 2 titanium in sheet form was processed by equal channel angular sheet extrusion (ECASE) up to two passes at room temperature. The ECASE process generated a heterogeneous state of deformation, mainly affecting the sheet metal edges´ vicinity. The deformation heterogeneity gave rise to notable microstructural changes throughout the sheet thickness with high densities of twins located around 600 μm from the sheet edges. At the same time, the middle zone was kept free of twins. The highest twin density generated with the ECASE process corresponds mostly to tension twins of type 10 1 ¯ 2 10 1 ¯ 1 oriented towards the extrusion direction. The heterogeneous structure produced a material strength increase of 200 MPa, maintaining a uniform deformation zone of 10%. The good strength-ductility combination was related to a heterogeneous distribution of geometrically necessary dislocations (GNDs) between the hardest and softest areas. The edge areas presented greater GNDs of type ⟨a⟩ on the twins' exterior than in their interior while in the middle zone, the highest GND densities grouped around triple points and grain boundaries. It was found that the grains with the most significant capacity to nucleate twins and store GNDs were those with the c-axis of the crystals parallel to the normal direction (ND). According to the Hall-Petch relationship, the strength improvement of the heterogeneous material comes from the grain size reduction mainly due to twins induced by deformation around the edge areas.

One of the major problems faced by metallic implants is the high probability of bacterial infections, with significant consequences for the patient. In this work, a thermochemical treatment is proposed to obtain silver-doped calcium titanate coatings on the Ti surface to improve the bioactivity of porous 3D-printed Ti structures and simultaneously provide them with antibacterial properties. A complete characterization of the new coating, the study of the ion release and the analysis of its cytotoxicity were carried out together with evaluation of the natural apatite forming in simulated body fluid (SBF). Moreover, the antibacterial properties of the coatings were assessed against Pseudomona aeruginosa and Escherichia coli as gram-negative and Staphylococcus aureus and Staphylococcus epidermidis as gram-positive bacterial strains. Ag ions were integrated into the Ca titanate layer and Ag nanoparticles were formed within the entire 3D Ti surface. Ca and Ag ions were released from both porous and solid samples into the Hanks' solution for 48 h. The treated surfaces showed no cytotoxicity and an apatite layer precipitated on the entire porous surface when the samples were immersed in SBF. The release of Ag from the surface had a strong antibacterial effect and prevented bacterial adhesion and proliferation on the surface. Moreover, the nanostructured topography of the coating resulted also in a reduction of bacterial adhesion and proliferation, even in absence of Ag. In conclusion, the cost-effective approach here reported provided protection against the most predominant bacterial colonizers to the Ti porous implants, while maintaining their bioactivity.

Background:The topographical features on the surface of dental implants have been considered as a critical parameter for enhancing the osseointegration of implants. In this work, we proposed a surface obtained by a combination of shot blasting and double acid etching. The double acid etching was hypothesized to increase the submicron topography and hence further stimulate the biological properties of the titanium implant.Methods:The topographical features (surface roughness and real surface area), wettability and surface chemical composition were analyzed.Results:The results showed that the proposed method produced a dual roughness, mainly composed of randomly distributed peaks and valleys with a superimposed nanoroughness, and hence with an increased specific surface area. Despite the fact that the proposed method does not introduce significant chemical changes, this treatment combination slightly increased the amount of titanium available on the surface, reducing potential surface contaminants. Furthermore, the surface showed increased contact angle values demonstrating an enhanced hydrophobicity on the surface. The biological behavior of the implants was then assessed by culturing osteoblast-like cells on the surface, showing enhanced osteoblast adhesion, proliferation and differentiation on the novel surface.Conclusions:Based on these results, the described surface with dual roughness obtained by double acid etching may be a novel route to obtain key features on the surface to enhance the osseointegration of the implant. Our approach is a simple method to obtain a dual roughness that mimics the bone structure modified by osteoclasts and increases surface area, which enhances osseointegration of dental implants.

Simple treatment of chiral titanium(IV) enolates with diacyl peroxides produces highly diastereoselective decarboxylative alkylations to efficiently deliver the corresponding adducts, most of which are not accessible through any of the current alkylating procedures. Such an unprecedented alkylation proceeds through an SET process that triggers the decomposition of the peroxide into a carbon-centered radical that finally combines with the resulting Cα radical. The procedure has been applied to the enantioselective synthesis of arundic acid.

Sixty-four fractured commercially pure titanium (cp-Ti) narrow dental implants (NDIs) with similar macrogeometry and connection designs were studied after different implantation times in humans in order to determine their reliability and to evaluate the causes of the fracture. These NDIs were compared with other similar implants, made with alloyed titanium with 15% Zr and with 12% strained titanium. Original implants were tested under static and fatigue conditions, simulating the tri-axial loads in the mouth by means of a Bionix hydraulic test machine. Fractography was studied using field-emission scanning electron microscopy (FSEM). The results showed that cp-Ti NDI exhibits low strength for mechanical cycling, and the alloyed Ti and strained titanium increase the mechanical strength, guaranteeing long term mechanical behavior. NDIs fractured due to fatigue, and, in some cases, the presence of cracks in the original NDIs quickly led to fracture. These cracks were attributed to plastic deformation during machining were found to be exacerbated due to acid etching in the passivation process. All cases of fracture were cp-Ti dental implants due to the low fatigue limit. The results show that, when titanium is alloyed or cold-worked, the fatigue limit is higher than cp-Ti. This in vitro research will help clinicians to select a better NDI system for safer treatment. info:eu-repo/semantics/acceptedVersion

Transition Metal Carbides (TMCs) are proposed to replace scarce and expensive late Transition Metals (TMs) as heterogeneous catalysts, often implying hydrogenation reactions or steps. Present density functional theory based calculations support using group IV TMCs and 𝜹-MoC as viable alternative catalysts to TMs for so, given the moderate exoergicity and affordable reaction step energy barriers.

The surface modifications of titanium dental implants play important roles in the enhancement of osseointegration. The objective of the present study was to test two different implant surface treatments on a rabbit model to investigate the osseointegration. The tested surfaces were: a) acid-etched surface with sandblasting treatment (SA) and b) an oxidized implant surface (OS). The roughness was measured by an interferometeric microscope with white light and the residual stress of the surfaces was measured with X-ray residual stress Bragg–Bentano diffraction. Six New Zealand white rabbits were used for the in vivo study. Implants with the two different surfaces (SA and OS) were inserted in the femoral bone. After 12 weeks of implantation, histological and histomorphometric analyses of the blocks containing the implants and the surrounding bone were performed. All the implants were correctly implanted and no signs of infection were observed. SA and OS surfaces were both surrounded by newly formed trabeculae. Histomorphometric analysis revealed that the bone–implant contact % (BIC) was higher around the SA implants (53.49 ± 8.46) than around the OS implants (50.94 ± 16.42), although there were no significant statistical differences among them. Both implant surfaces (SA and OS) demonstrated a good bone response with significant amounts of newly formed bone along the implant surface after 12 weeks of implantation. These results confirmed the importance of the topography and physico–chemical properties of dental implants in the osseointegration. The authors are grateful to the Spanish Government and European Union FEDER by the concession of the project RTI2018-098075-B-C22 SI

Titanium(III) complexes containing unprecedented (NH2BH2NHBH3)2‒ and {N(BH3)3}3‒ ligands have been isolated and their structures elucidated by a combination of experimental and theoretical methods. The treatment of the trimethyl derivative [TiCp*Me3] (Cp* = η5-C5Me5) with NH3BH3 (3 equiv) at room temperature gives the paramagnetic dinuclear complex [{TiCp*(NH2BH3)}2(μ-NH2BH2NHBH3)], which at 80 ºC leads to the trinuclear hydride derivative [{TiCp*(μ-H)}3{μ3-N(BH3)3}]. The bonding modes of the anionic BN fragments in those complexes as well as the dimethylaminoborane group trapped on the analogous trinuclear [{TiCp*(μ-H)}3(μ3-H)(μ3-NMe2BH2)] have been studied by X-ray crystallography and density functional theory (DFT) calculations., Ministerio de Economía y Competitividad de España, Universidad de Alcalá

El primer mineral de titanio, una arena negra de Cornualles (Gran Bretaña), fue identificado en 1791 por William Gregor, un clérigo inglés y geólogo aficionado, del que extrajo un óxido de un metal desconocido. En 1795, el químico alemán Martin Heinrich Klaproth investigando una turmalina roja de Hungría detectó el óxido de un nuevo elemento, que resultó ser el descrito por Gregor, al que llamó titanio, en alusión los Titanes, los hijos de la diosa Tierra en la mitología griega.