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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.

Aquest projecte Final de Grau s’ha realitzat en les instal·lacions del Campus Universitat UPC de l’Escola d’Enginyeria de Barcelona de l’Est (EEBE). Concretament amb el grup de recerca de Biomaterials, Biomecànica i Enginyeria de Teixits (BBT). S’ha desenvolupat un recobriment antifouling sobre la superfície de titani carregat amb una concentració d’antibiòtic. El recobriment emprat es tracta d’un recobriment per polímer PEG polimeritzat per Dyglyme a diferents condicions. S’ha analitzat S’analitzarà la superfície de Titani en les diferents mostres realitzades i el comportament de l’antibiòtic sobre la superfície. Els anàlisis establerts s’han dut a terme a diferents nivells de caracterització: químic, superficial i biològic. En primer lloc, a nivell químic mitjançant els espectres per FTIR i la tècnica XPS s’ha analitzat els components químics que composen la superfície per confirmar si es tracta d’un recobriment de PEG. En segon lloc, a nivell superficial s’ha estudiat estudia l’Energia Lliure Superficial que adquireix cada mostra segons el tractament i el seu grau de comportament hidrofòbic. En tercer lloc, a nivell biològic s’ha demostrat que es tracta d’un recobriment de PEG antifouling, ja que redueix l’adhesió antibacteriana a la superfície de titani i mitjançant el Double-Well test s’ha l’efecte que té el tractament d’antibiòtic en la proliferació bacteriana. Finalment, s’afirma que s’ha desenvolupat un recobriment de PEG antifouling per polimerització de Dyglyme sobre la superfície de titani. El tractament d’antibiòtic en el recobriment de PEG antifouling es confirma que redueix l’adhesió bacteriana més significativament però el seu efecte en la proliferació bacteriana no ha estat l’esperat. Este proyecto Final de Grado se ha realizado en las instalaciones del Campus Diagonal Besós de la Universidad Politécnica de Catalunya(UPC), en la Escuela de Ingeniería de Barcelona del Este(EEBE). Concretamente con el grupo de recerca de Biomateriales, Biomecánica e Ingeniería de Tejidos(BBT). Se ha desarrollado un recubrimiento de PEG antifouling sobre la superficie de titanio cargado con una concentración de antibiótico. Se ha analizado la superficie de titanio de las diferentes muestras tratadas i el comportamiento que adopta el antibiótico sobre la superficie. Los diferentes análisis realizados se han hecho a tres niveles de caracterización: superficial, química i biológica. La caracterización química se ha realizado mediante diferentes espectros FTIR i la técnica XPS. Se ha determinado los diferentes componentes químicos que constituyen la superficie de las muestras . Se ha comparado con la estructura química de un polímero PEG para confirmar si el recubrimiento se trata de un recubrimiento de PEG. A nivel superficial, se ha estudiado la Energía Libre Superficial que presentan las diferentes muestras tratadas según su tratamiento i su comportamiento hidrófobo. A partir de la caracterización biológica mediante adhesión bacteriana, se ha demostrado que el recubrimiento formado de PEG se trata de un recubrimiento de PEG antifouling debido a su reducción de adhesión bacteriana en su superficie. Mediante el Double-Well Test se ha estudiado el efecto del tratamiento de antibiótico en la proliferación bacteriana. Finalmente, se afirma el desarrollo de un recubrimiento de PEG antifouling por polimerización de Dyglyme sobre la superficie de Titanio. El tratamiento de antibiótico en la superficie de titanio con recubrimiento de PEG, confirma que reduce la adhesión bacteriana más significativa pero su efecto en la proliferación bacteriana no es el esperado. This Final Degree Project of Biomedical Engineering was done in the Universitat Politècnica of Catalunya, in the Engineering School of Barcelona East (EEBE). To be specific, was done inside the researching group of Biomaterials, Biomechanic and Engineering Tissue. An antifouling polymeric coating has been developed in the titanium surface with a concentration of antibiotic. The titanium surface of treated samples by polymerization and the behaviour adopted by the antibiotic surface has been analysed. The different analyses carried out have been made at three levels of characterization: superficial, chemical and biological. The chemical characterization has been carried out using different FTIR spectra and the XPS technique. The different chemical components of the surface have been found out. A comparation between the know chemical structure of the polymer PEG and the chemical components found out order to determine if it’s a PEG coating. At a superficial level, the Surface Free Energy presented by the different samples treated according to their conditions and their hydrophobic behaviour has been studied. The biological characterizations has been analysed by bacterial adhesion. It has been shown that PEG coating is an antifouling PEG counting due to its reduction of bacterial adhesion on its surface. Using the Double-Well test, the effect of the antibiotic on bacterial proliferation has been studies. To conclude, the development of an antifouling PEG coating by Dyglyme polymerization on the titanium surface has been confirmed. Antibiotic treatment on the PEG coating confirms that it reduces much better the bacterial adhesion, but its effect on bacterial proliferation is not as expected.

International audience; Implants for orthopedic applications need to be biocompatible and bioactive, with mechanical properties similar to those of surrounding natural bone. Given this scenario titanium (Ti) scaffolds obtained by Direct Ink Writing technique offer the opportunity to manufacture customized structures with controlled porosity and mechanical properties. Considering that 3D Ti scaffolds have a significant surface area, it is necessary to develop strategies against the initial bacterial adhesion in order to prevent infection in the early stages of the implantation, while promoting cell adhesion to the scaffold. The challenge is not only achieving a balance between antibacterial activity and osseointegration, it is also to develop a homogeneous coating on the inner and outer surface of the scaffold. The purpose of this work was the development of a single-step electrodeposition process in order to uniformly cover Ti scaffolds with a layer of calcium phosphate (CaP) loaded with chlorhexidine digluconate (CHX). Scaffold characterization was assessed by scanning electron microscopy, Energy dispersive X-ray spectroscopy, X-ray diffraction, micro-Raman microscopy and compressive strength tests. Results determined that the surface of scaffolds was covered by plate-like and whisker-like calcium phosphate crystals, which main phases were octacalcium phosphate and brushite. Biological tests showed that the as-coated scaffolds reduced bacteria adhesion (73 ± 3% for Staphylococcus aureus and 70 ± 2% for Escherichia coli). In vitro cell studies and confocal analysis revealed the adhesion and spreading of osteoblast-like SaOS-2 on coated surfaces. Therefore, the proposed strategy can be a potential candidate in bone replacing surgeries.

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.

En aquest estudi s’ha analitzat la toxicitat de les partícules de titani que es generen durant el procés conegut com a implantoplàstia dental. Les partícules metàl·liques generades durant el procés de implantoplàstia poden comportar greus complicacions per al correcte funcionament de l’implant dental implantat, com ara la pèrdua de densitat òssia del teixit circumdant a l’implant que donaria lloc a una pèrdua de fixació de l’implant i al conseqüent increment del risc d’infecció. Entre els principals factors que poden condicionar l’efecte en l’organisme de les partícules metàl·liques, destacarien el tipus de material, la mida de partícula, la superfície específica, la geometria, entre d’altres. Per això, en aquest treball per tal de caracteritzar aquestes partícules s’han dut a terme un conjunt d’assajos com ara microscòpia electrònica de rastreig (SEM), anàlisi d’alliberació d’ions (IONRELEASE), granulometria làser, espectroscòpia de raig X i assaigs biològics de citotoxicitat cel·lular. Finalment, s’ha observat com, a l’estudiar els resultats obtinguts del conjunt d’assajos, s’ha pogut establir certa relació entre la mida de partícula i la corresponent superfície especifica, amb l’alliberació d’ions al medi i en conseqüència la toxicitat que representa per l’organisme. Així doncs, a menor mida de partícula, també és menor el percentatge de supervivència cel·lular. En este estudio se ha analizado la toxicidad de las partículas de titanio que se generan durante el proceso de la implantoplàstia dental. Las partículas metálicas generadas durante el proceso de implantoplàstia pueden conllevar graves complicaciones para el correcto funcionamiento del implante dental implantado, como la pérdida de densidad ósea del tejido circundante al implante que daría lugar a una pérdida de fijación del implante y al consecuente incremento del riesgo de infección. De entre los principales factores que pueden condicionar el efecto en el organismo de las partículas metálicas, destacarían el tipo de material, el tamaño de partícula, la superficie específica, la geometría, entre otros. Por ello, en este trabajo con el fin de caracterizar estas partículas se han llevado a cabo un conjunto de ensayos tales como microscopía electrónica de barrido (SEM), análisis de liberación de iones (ION-RELEASE), granulometría laser, espectroscopía de rayos X y ensayos biológicos de citotoxicidad celular. Finalmente, se ha observado como, al estudiar los resultados obtenidos del conjunto de ensayos, se ha podido establecer cierta relación entre el tamaño de partícula y la correspondiente superficie específica, con la liberación de iones al medio y en consecuencia la toxicidad que representa para el organismo. Así, a menor tamaño de partícula, también es menor el porcentaje de supervivencia celular. This study looked at the toxicity of titanium particles that are generated during the process known as dental implantoplasty. Metal particles generated during the implantoplasty process can lead to serious complications for the proper functioning of the implanted dental implant, such as the loss of bone density of the tissue surrounding the implant that would result in a loss of fixation of the implant and the consequent increase in the risk of infection. Among the main factors that can condition the effect on the body of metal particles are the type of material, particle size, specific surface area, geometry, among others. Therefore, in this study, in order to characterize these particles a set of tests such as scanning electron microscopy (SEM), ion release, laser granulometry, X-ray spectroscopy and biological tests for cellular cytotoxicity. Finally, the study of the results obtained after the experiments, allowed to establish a certain relation between the particle size and its specific surface, with the ion release and the toxicity that represents for the organism. Therefore, the smaller the particle size is, the less percentage of cellular viability exists.

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

[ES] Las infecciones periprostéticas (IPP) son causadas por microorganismos que colonizan prótesis, siendo los principales causantes el S.epidermidis y S.aureus. En la literatura científica se ha abordado la interacción bacteria-sustrato en superficies funcionalizadas de Ti6Al4V, sin estudiar la influencia de su microestructura, la cual depende del método de fabricación empleado (fabricación aditiva) o tratamiento aplicado (forjado). El objetivo de este estudio es desarrollar aleaciones de Ti6Al4V mediante forja, EBM y DMLS y comprobar el efecto que tiene la microestructura de cada una de ellas en la adhesión y colonización de bacterias (S.epidermidis y S.aureus). Para ello se caracterizaron microestructural, mecánica y biológicamente muestras de Ti6Al4V de forja, EBM y DMLS mediante: difracción de Rayos X, microscopía óptica, microscopía electrónica de barrido, perfilometría óptica, ensayo de dureza y microdureza, ensayo de cultivo bacteriano y microscopía confocal de fluorescencia. Los resultados muestran un patrón de XRD similar entre muestras, con mayor presencia de Tiα en las de fabricación aditiva. La microestructura característica en las muestras de forjado fue de mill annealing, en EBM y una de DMLS sometida a recocido fue de Windmastätten mientras que en la otra de DMLS fue martensítica con acículas de Tiα’. La rugosidad fue similar entre todas las muestras (>0,5 µm). La microdureza fue semejante entre muestras, mientras que en la dureza la muestra DMLS recocida presentó el menor valor. Debido a la elevada dispersión no se pudieron obtener datos concluyentes del ensayo de cultivo, pero las muestras de fabricación aditiva presentaron una tendencia a mayor colonización, especialmente las de DMLS (entre 134-155% más de UFC/cm2ml para S.aureus, y 80-119% para S.epidermidis en la dilución 10-3 vs. forjado). En la microscopía confocal destaca la ausencia de muerte bacteriana después de 48h de cultivo y la mayor colonización de las muestras de fabricación aditiva, al igual que en el FESEM., [CA] Les infeccions periprostètiques (IPP) són causades per microorganismes que colonitzen pròtesis, sent els principals causants el S.epidermidis i S.aureus. En la literatura científica s'ha abordat la interacció bacteri-substrat en superfícies funcionalitzades de Ti6Al4V, sense estudiar la influència de la seua microestructura, la qual depén del mètode de fabricació emprat (fabricació additiva) o tractament aplicat (forjat). L'objectiu d'aquest estudi és desenvolupar aliatges de Ti6Al4V mitjançant forja, EBM i DMLS i comprovar l'efecte que té la microestructura de cadascuna d'elles en l'adhesió i colonització de bacteris (S.epidermidis i S.aureus). Per a això es van caracteritzar microestructural, mecànica i biològicament mostres de Ti6Al4V de forja, EBM i DMLS mitjançant: difracció de Raigs X, microscòpia òptica, microscòpia electrònica d'escombratge, perfilometría òptica, assaig de duresa i microduresa, assaig de cultiu bacterià i microscòpia confocal de fluorescència. Els resultats mostren un patró de XRD similar entre mostres, amb major presència de Tiα en les de fabricació additiva. La microestructura característica en les mostres de forjat va ser de mill annealing, en EBM i una de DMLS sotmesa a recuita va ser de Windmastätten mentre que en l'altra de DMLS va ser martensítica amb acícules de Tiα’. La rugositat va ser similar entre totes les mostres (>0,5 µm). La microduresa va ser semblant entre mostres, mentre que en la duresa la mostra DMLS recuita va presentar el menor valor. A causa de l'elevada dispersió no es van poder obtindre dades concloents de l'assaig de cultiu, però les mostres de fabricació additiva van presentar una tendència a major colonització, especialment les de DMLS (entre 134-155% més de UFC/cm2ml per a S.aureus, i 80-119% per a S.epidermidis en la dilució 10-3 vs. forjat). En la microscòpia confocal destaca l'absència de mort bacteriana després de 48h de cultiu i la major colonització de les mostres de fabricació additiva, igual que en el FESEM., [EN] The periprosthesis infections (PPI) are caused by microorganisms that colonize prosthesis, being the main causes the S.epidermidis and S.aureus. Scientific literature has addressed the interaction between bacteria and substrate in functionalized surfaces of Ti6Al4V, without studying the influence of its microstructure, which depends on the manufacturing method used (additive manufacturing) or treatment applied (forging). The aim of this study is to develop Ti6Al4V alloys by means of forging, EBM and DMLS and to check the effect of the microstructure of each one of them has on the adhesion and colonization of bacteria (S.epidermidis and S.aureus). For this purpose, microstructural, mechanical and biological samples of Ti6Al4V from forging, EBM and DMLS were characterized by means of: X-ray diffraction, optical microscopy, scanning electron microscopy, optical profilometry, hardness and microhardness test, bacterial culture test and fluorescence confocal microscopy. The results show a similar XRD pattern among samples, with a higher presence of Tiα in the additive manufacturing ones. The characteristic microstructure in the forging samples was of mill annealing, in EBM and one of DMLS submitted to annealing was of Windmastätten while in the other of DMLS it was martensitic with Tiα' needles. The roughness was similar among all samples (>0.5 µm). The microhardness was similar among samples, while in hardness the annealed DMLS sample presented the lowest value. Due to the high dispersion, it was not possible to obtain conclusive data from the culture test, but the samples of additive manufacture showed a tendency to higher colonization, especially those of DMLS (between 134-155% more CFU/cm2ml for S.aureus, and 80-119% for S.epidermidis in the 10-3 vs. forged dilution). In confocal microscopy, the absence of bacterial death after 48h of culture and the greater colonization of the samples of additive manufacture stand out, as in the FESEM.

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.

[ES] La manufactura aditiva (MA) se ha convertido en una herramienta de fabricación muy atractiva en la actualidad y el interés en su empleo en sectores como el aeroespacial, biomédico, marino o en la generación de energía, entre otros, se encuentra en auge. Principalmente por la enorme flexibilidad que ofrece a la hora de fabricar piezas con geometrías y diseños con un elevado grado de complejidad. Este tipo de técnica de fabricación permite la obtención de estructuras metálicas huecas, reticuladas y con cavidades internas complejas, lo que abre las puertas a la posibilidad de producir componentes ultraligeros de forma sencilla. Esta característica hace que se considere a la manufactura aditiva como un camino sostenible para la producción de componentes metálicos, ya que permite reducciones sustanciales en el uso de materia prima y generación de residuos en comparación con los métodos de manufactura convencional. Sin embargo, uno de los principales problemas que se presenta con la manufactura aditiva es la heterogeneidad de las propiedades obtenidas durante el proceso de producción, que pueden verse afectadas por las diferencias en los parámetros de impresión, la orientación de los componentes durante la impresión o las diferencias de tamaños. Por ello, el empleo de la manufactura aditiva se ha visto frenado en aplicaciones críticas, y es crucial llegar a un completo conocimiento de las propiedades mecánicas, así como su relación con el proceso de fabricación y la microestructura obtenida. Las aleaciones de titanio, y en particular la aleación Ti-6Al-4V, que representa más del 50% de la producción mundial de titanio, son las principales aleaciones empleadas en sectores como el aeroespacial o la biomedicina gracias a su elevada resistencia específica y rigidez estructural, su excelente resistencia a la corrosión y medios agresivos y su excelente comportamiento mecánico a altas temperaturas. Sin embargo, el coste de producción de las aleaciones de titanio representa un limitante a la expansión en el uso de estas aleaciones. La manufactura convencional del titanio requiere un elevado consumo de energía y generalmente produce una elevada cantidad de material de desecho, ya que se requiere una gran cantidad de mecanizado posterior hasta alcanzar la forma final de los componentes. La manufactura aditiva se presenta como una posible solución a los elevados costes de producción de la manufactura convencional. Algunos estudios sitúan a los sistemas SLM (Selective Laser Melting) como la técnica de manufactura aditiva más prometedora. Estos permiten la producción de componentes con una densidad media superior al 99.8% y por ello, las aleaciones obtenidas por SLM presentan propiedades mecánicas comparables a las obtenidas mediante manufactura convencional. Sin embargo, gran parte de los estudios realizados se centra en la optimización de los parámetros de producción de los sistemas de MA para aumentar la densidad obtenida, de forma que se reducen los defectos internos, pero sin llegar a tener en cuenta el efecto microestructural, por lo que se carece de un estudio extenso que agrupe y permita entender el efecto de diferentes orientaciones, formatos y tamaños sobre la microestructura en SLM. Para entender las propiedades mecánicas del Ti-6Al-4V en SLM se debe entender los efectos producidos a nivel microestructural y químico, y éste es el propósito de este trabajo: presentar un estudio sistemático del efecto de la orientación de impresión, el tamaño de impresión y el formato de impresión en la microestructura obtenida y la composición química local y cómo estas se relacionan con las propiedades mecánicas del Ti-6Al-4V. La estructura seguida en el trabajo será: Realizar una revisión de las propiedades de las aleaciones de titanio y los métodos de obtención mediante manufactura convencional, junto a una revisión del estado del arte de la manufactura aditiva, centrándose en l, [EN] Additive manufacturing (AM) has become a very attractive manufacturing tool at present and the interest in its use in sectors such as aerospace, biomedical, marine or in the generation of energy, among others , is booming. Mainly because of the enormous flexibility it offers when manufacturing pieces with geometries and designs with a high degree of complexity. This type of manufacturing technique allows obtaining hollow, cross-linked metallic structures with complex internal cavities, which opens the doors to the possibility of producing ultralight components in a simple way. This characteristic means that additive manufacturing is considered a sustainable path for the production of metallic components, since it allows substantial reductions in the use of raw materials and generation of waste compared to conventional manufacturing methods. However, one of the main problems with additive manufacturing is the heterogeneity of the properties obtained during the production process, which can be affected by the differences in the printing parameters, the orientation of the components during printing or the differences in sizes. Therefore, the use of additive manufacturing has been slowed down in critical applications, and it is crucial to arrive at a complete knowledge of the mechanical properties, as well as its relationship with the manufacturing process and the obtained microstructure. The titanium alloys, and in particular the alloy Ti-6Al-4V, which represents more than 50% of the world production of titanium, are the main alloys used in sectors such as aerospace or biomedicine thanks to their high specific resistance and rigidity structural, its excellent resistance to corrosion and aggressive media and its excellent mechanical behavior at high temperatures. However, the production cost of titanium alloys represents a limitation to the expansion in the use of these alloys. The conventional manufacture of titanium requires a high energy consumption and generally produces a high amount of waste material, since a large amount of subsequent machining is required to reach the final shape of the components. Additive manufacturing is presented as a possible solution to the high production costs of conventional manufacturing. Some studies place the SLM (Selective Laser Melting) systems as the most promising additive manufacturing technique. These allow the production of components with an average density higher than 99.8% and therefore, the alloys obtained by SLM have mechanical properties comparable to those obtained by conventional manufacturing. However, a large part of the studies carried out focus on optimizing the production parameters of MA systems to increase the density obtained, so that internal defects are reduced, but without taking into account the microstructural effect, therefore, it lacks an extensive study that groups and allows understanding the effect of different orientations, formats and sizes on the microstructure in SLM. To understand the mechanical properties of Ti-6Al-4V in SLM one must understand the effects produced at the microstructural and chemical level, and this is the purpose of this work: to present a systematic study of the effect of the printing orientation, the printing size and the printing format in the obtained microstructure and the local chemical composition and how they relate to the mechanical properties of Ti-6Al-4V. The structure followed in the work will be: Perform a review of the properties of titanium alloys and the methods of obtaining by conventional manufacturing, together with a review of the state of the art of additive manufacturing, focusing on SLM systems. Subsequently the methodology and materials used to carry out the study will be described, and finally the results will be presented discussing them conveniently., [CA] Aquest treball presenta un estudi sobre les propietats mecàniques de l’aleació de titani Ti-6Al-4V obtingut mitjançant manufactura additiva amb fusió selectiva per láser (SLM). Es presenta i descriu l’efecte que té sobre la resistència i ductilitat diferents paràmetres: (1) la grossària de les mostres, que varia entre 0.25 mm y 3 mm, (2) la direcció d’impressió, presentant 3 direccions, ZZ, XZ i XY, i (3) el format d’impressió, emprant 3 formats diferents. L’estudi del efecte d’aquests paràmetres el realitza tant amb assajos a tracció com a tallant. A més de l’efecte d’aquests paràmetres sobre les propietats mecàniques, també es realitza un anàlisi microestructural, un anàlisi químic de la concentració d’oxigen i un anàlisi de la qualitat superficial amb l’objectiu de relacionar les variacions en aquests camps amb els efectes observats sobre la resistència i ductilitat en els diferents casos d’estudi.

Quan un os pateix una patologia o fractura, en molts casos necessita ajuda externa per reparar-se i regenerar-se completament per tornar a ser funcional. La demanda de dispositius de substitució òssia ha augmentat al llarg dels anys, degut a l’augment de l’esperança de vida de la població. Actualment, existeixen diferents biomaterials utilitzats per a la regeneració del teixit ossi. L’ús de transplantaments (o grafts) és una de les vies més utilitzades, però a poc a poc, la demanda de materials sintètics per reparació òssia va prenent més importància. Aquests últims presenten diversos avantatges front els grafts, com per exemple la disminució de possibilitat d’infecció o resposta immunològica. Per contra, un dels principals problemes de l’ús de materials sintètics és la falta de bioactivitat, per la qual cosa, s’han desenvolupat tècniques de modificació superficial per millorar la interacció entre l’implant i l’entorn fisiològic. L’ús de biomolècules que imiten la matriu extracel·lular per recobrir els materials està sent àmpliament investigat amb aquesta finalitat. Per augmentar la bioactivitat i osteoinducció de biomaterials usats en aplicacions òssies, com és el cas del titani, es va descriure recentment una nova molècula multifuncional que conté el motiu RGD i un pèptid derivat de la BMP-2 (DWIVA). Estudis previs amb aquesta plataforma han mostrat un augment de l’adhesió cel·lular i la mineralització d’osteoblasts sobre substrats de vidre i titani. Un aspecte cabdal en la funcionalització de superfícies és l’estudi de la interacció entre els recobriments i el substrat. En aquest treball, s’ha utilitzat la molècula DOPA per ancorar la plataforma peptídica als diversos materials. Aquesta molècula es troba present a les proteïnes secretades pels mol·luscs per ancorar-se a les roques en condicions humides, i presenta un gran potencial per unir-se a diverses superfícies. En particular, la DOPA conté un grup catecol que permet una forta unió amb òxids metàl·lics. L’avantatge que presenta aquesta unió front altres mètodes de funcionalització és que els substrats no necessiten un tractament previ i les molècules es poden ancorar fàcilment mitjançant un procés d’immersió, la qual cosa redueix el temps d’immobilització i la complexitat del procés. L’objectiu principal d’aquest treball és la caracterització fisicoquímica dels substrats de vidre i titani recoberts amb la plataforma prèviament anomenada. La mullabilitat, composició química, la densitat del pèptid sobre la superfície, així com l’espessor i la distribució de la plataforma sobre el substrat, a més de l’estabilitat de l’enllaç, són els paràmetres que s’han analitzat al llarg de tot el treball. Una vegada funcionalitzats els substrats, s’ha pogut verificar la presència de la plataforma sobre les superfícies. S’han obtingut valors de densitats de pèptid sobre ambdues superfícies superiors als obtinguts per altres mètodes d’immobilització i s’ha aconseguit obtenir una distribució homogènia de la plataforma sobre els substrats de vidre i titani.

Biomimetic design is a key tenet of orthopedic device technology, and in particular the development of responsive surfaces that promote ion exchange with interfacing tissues, facilitating the ionic events that occur naturally during bone repair, hold promise in orthopedic fixation strategies. Non-bioactive nanostructured titanium implants treated by shot-blasting and acid-etching (AE) induced higher bone implant contact (BIC=52% and 65%) compared to shot-blasted treated (SB) implants (BIC=46% and 47%) at weeks 4 and 8, respectively. However, bioactive charged implants produced by plasma (PL) or thermochemical (BIO) processes exhibited enhanced osteoconductivity through specific ionic surface-tissue exchange (PL, BIC= 69% and 77% and BIO, BIC= 85% and 87% at weeks 4 and 8 respectively). Furthermore, bioactive surfaces (PL and BIO) showed functional mechanical stability (resonance frequency analyses) as early as 4 weeks post implantation via increased total bone area (BAT=56% and 59%) ingrowth compared to SB (BAT=35%) and AE (BAT=35%) surfaces. info:eu-repo/semantics/acceptedVersion