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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 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.

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.

[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.

[ES] El titanio es uno de los elementos metálicos más abundantes de la naturaleza, que tiene importantes propiedades y características que lo hacen único y ampliamente demandado en el sector industrial. En particular, las aleaciones de titanio son las protagonistas en el sector biomédico, ya que, al presentar un módulo bajo de elasticidad, baja conductividad térmica y eléctrica, y una alta resistencia a la corrosión, son las seleccionadas para la fabricación de implantes y prótesis biomédicas. Sin embargo, se ha de tener cuidado con su manipulación porque es altamente reactivo cuando está en presencia de oxígeno, teniendo asociados unos riesgos considerables. En este trabajo, las aleaciones de titanio de las que se estudia su biocompatibilidad han sido procesadas por vía pulvimetalúrgica. Esta técnica es la más común para obtener y diseñar composiciones que pueden ser difíciles de obtener por metalurgia convencional, disminuyendo la cantidad de residuos del material durante el procesamiento e impidiendo que los elementos de aleación sean segregados (garantizando la homogeneidad de la microestructura). Se trata pues con aleaciones formadas por la mezcla elemental y el aliado mecánico de los polvos de los elementos de aleación, cuyas propiedades mecánicas han sido determinadas por una prueba de dureza y flexión de tres puntos; mientras que la caracterización microestructural se ha analizado mediante la microscopía electrónica de barrido. La biocompatibilidad es un término relativo que cubre muchos conceptos, y que indica la capacidad de un material para realizar una función biológica sin producir una reacción a un cuerpo extraño. Entonces, las aleaciones han sido sometidas a una prueba de resistencia a la corrosión, junto con una prueba de liberación de iones con saliva artificial durante 732 horas. Luego, para ver el efecto de los resultados de las pruebas anteriores y empleando una línea celular de osteosarcoma humano (MG63), se ha hecho una determinación de la toxicidad con el reactivo MTS, y posteriormente se ha realizado un ensayo de adhesión celular y proliferación, de 5 horas y 72 horas respectivamente. Por lo tanto, los resultados del estudio de las diferentes aleaciones de titanio caracterizadas por la presencia de un elemento de aleación en cada caso permiten determinar si se comportan como verdaderos biomateriales o resultan nocivos para un medio biológico., [CA] El titani es un dels elements metàl·lics més abundants de la naturalesa, que posseeix unes importants propietats i característiques que el fan únic i àmpliament demandat en el sector industrial. Concretament, els aliatges de titani son els protagonistes en el sector biomèdic ja que al presentar un baix mòdul d’elasticitat, baixa conductivitat tèrmica i elèctrica, i una elevada resistència a la corrosió, son els seleccionats per a la fabricació d’implants i pròtesis biomèdiques. No obstant, es deu de tindre en conter amb la seua manipulació ja que és altament reactiu quan es troba en presencia d’oxigen , ocasionant uns riscos considerables. En aquest treball, els aliatges de titani dels quals s’estudia la seua biocompatibilitat, han sigut processades per via pulvimetal·lúrgica. Aquesta tècnica es la més comú per a l’obtenció i disseny de composicions que puguin ser difícils d’obtenir mitjançant la metal·lúrgia convencional, disminuint la quantitat de deixalles del material durant el processat i evitant que els elements d’aliatge es segreguen (garantint la homogeneïtat de la microestructura). Es tracta amb aliatges resultats de la mescla elemental i aliat mecànic dels pols dels elements d’aliatge, les propietats mecàniques dels quals s’han determinat per una prova de duresa i de flexió a tres punts; mentre que la caracterització microestructural ha sigut analitzada per microscòpia electrònica d’escombrat. La biocompatibilitat, es un terme relatiu que engloba molts conceptes, i que indica la capacitat d’un material de realitzar una funció biològica sense produir una reacció a cos estrany. Aleshores, per estudiar-lo, primerament, s’han sotmès els aliatges a una prova de resistència a la corrosió junt a una d’alliberament d’ions amb saliva artificial durant 732 hores. A continuació, per veure l’efecte dels resultats de les proves anteriors i fent ús d’una línia cel·lular d’osteosarcoma humà (MG-63), s’ha realitzat una determinació de la toxicitat amb el reactiu MTS, i després un assaig d’adhesió i proliferació cel·lular, de 5 hores i 72 hores respectivament. Per tant, els resultats de l’estudi dels diferents aliatges de titani caracteritzats per la presencia d’un element d’aliatge en cada cas, permeten determinar si aquests es comporten com a vertaders biomaterials o resulten perjudicials per al medi biològic., [EN] Titanium is one of the most abundant metal elements of nature, which has important properties and characteristics that make it unique and widely demanded in the industrial sector. Specifically, the titanium alloys are the protagonists in the biomedical sector as by presenting a low modulus of elasticity, low thermal and electrical conductivity, and a high resistance to corrosion, are those selected for the manufacture of implants and biomedical prostheses. However, their manipulation is complicated because it is highly reactive when it is in the presence of oxygen. In this work, the titanium alloys have been processed by powder metallurgical route. This technique is the most common to obtain and design compositions that can be difficult to obtain by conventional metallurgy, amount of material waste during processing and preventing the alloy elements from being segregated (guaranteeing the homogeneity of the microstructure). They are alloys formed by the elementary mixture and the mechanical alloy of the powders of the alloy elements, whose mechanical properties have been determined by a three-point hardness and flexural test; while the microstructural characterization has been analyzed by scanning electron microscopy. Biocompatibility is a relative term that covers many concepts, and that indicates the ability of a material to perform a biological function without producing a reaction to a foreign body. Then, the alloys have been subjected to a corrosion resistance test, and an ion release test with artificial saliva for 732 hours. Then, to see the effect of the results of the previous tests and using a human osteosarcoma cell line (MG-63), a toxicity determination was made with the MTS reagent, and subsequently a 5-hour and 72-hour cell adhesion and proliferation test was performed respectively. Therefore, the results of the study of the different titanium alloys characterized by the presence of an alloy element in each case, allow to determine whether they behave as true biomaterials or are harmful to a biological environment.

Three different surface treatments on a Ti6Al4V alloy have been in vitro tested for possible application in cementless joint prosthesis. All of them involve the novelty of using the Cold Spray technology for their deposition: (i) an as-sprayed highly rough titanium and, followed by the deposition of a thin hydroxyapatite layer with (ii) microcrystalline or (iii) nanocrystalline structure. Primary human osteoblasts were extracted from knee and seeded onto the three different surfaces. Cell viability was tested by MTS and LIVE/DEAD assays, cell differentiation by alkaline phosphatase (ALP) quantification and cell morphology by Phalloidin staining. All tests were carried out at 1, 7 and 14 days of cell culture. Different cell morphologies between titanium and hydroxyapatite surfaces were exhibited. At 1 day of cell culture, cells on the titanium coating were spread and flattened, expanding the filopodia actin filaments in all directions, while cells on the hydroxyapatite coatings showed round like-shape morphology due to slower attachment. Higher cell viability was detected at all times of cell culture on titanium coating due to a better attachment at 1 day. However, from 7 days of cell culture, cells on hydroxyapatite showed good attachment onto surfaces and highly increased their proliferation, mostly on nanocrystalline, achieving similar cell viability levels than titanium coatings. ALP levels were significantly higher in titanium, in part, because of greatest cell number. Overall, the best cell functional results were obtained on titanium coatings whereas microcrystalline hydroxyapatite presented the worst cellular parameters. However, results indicate that nanocrystalline hydroxyapatite coatings may achieve promising results for the faster cell proliferation once cells are attached on the surface.

Highly rough and porous commercially pure titanium coatings have been directly produced for first time by the cold spray technology, which is a promising technology in front of the vacuum plasma spray for oxygen sensitive materials. The wettability properties as well as the biocompatibility evaluation have been compared to a simply sand blasted Ti6Al4V alloy substrate. Surface topographies were analysed using confocal microscopy. Next, osteoblast morphology (Phalloidin staining), proliferation (MTS assay), and differentiation (alkaline phosphatase activity) were examined along 1, 7 and 14 days of cell culture on the different surfaces. Finally, mineralization by alizarin red staining was quantified at 28 days of cell culture. The contact angle values showed an increased hydrophilic behaviour on the as-sprayed surface with a good correlation to the biological response. A higher cell viability, proliferation and differentiation were obtained for highly rough commercial pure titanium coatings in comparison with sand blasted substrates. Cell morphology was similar in all coatings tested; at 14 days both samples showed extended filopodia. A higher amount of calcium-rich deposits was detected on highly rough surfaces. In summary, in-vitro results showed an increase of biological properties when surface roughness increases. The authors want to thank the Spanish MINECO for financial support through project MAT2013-46755-R and the Generalitat de Catalunya for the project 2014 SGR 1558, and University of Barcelona for the award of a scholarship that has helped the development of this research. This work was also supported by the Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF; RD12/0043/0022), the Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES; CB16/10/00245) and FEDER funds.

Hierarchical structures were obtained applying two different nanotexturing surface treatments onto highly rough commercial pure titanium coatings by cold spray: (i) anodic oxidation and (ii) alkaline treatments. An extended surface characterization in terms of topography, composition, and wettability has been performed to understand how those parameters affect to cell response. Primary human osteoblasts extracted from knee were seeded onto the as-sprayed titanium surface before and after the nanotexturing treatments. Cell viability was tested by using MTS and LIVE/DEAD assays, as well as osteoblasts differentiation by alkaline phosphatase (ALP) quantification at 3 and 10 days of cell culture. The combination of micro-/nano-roughness results in a significantly increase of cell proliferation, as well as cell differentiation after 10 days of cell culture in comparison with the non-treated coatings.

Bacterial infection represents a major cause of implant failure in dentistry. A common approach to overcoming this issue and treating pen-implant infection consists in the use of antibiotics. However, the rise of multidrug-resistant bacteria poses serious concerns to this strategy. A promising alternative is the use of antimicrobial peptides due to their broad-spectrum activity against bacteria and reduced bacterial resistance responses. The aim of the present study was to determine the in vitro antibacterial activity of the human lactoferrin-derived peptide hLf1-11 anchored to titanium surfaces. To this end, titanium samples were functionalized with the hLf1-11 peptide either by silanization methods or physical adsorption. X-ray photoelectron spectroscopy analyses confirmed the successful covalent attachment of the hLf1-11 peptide onto titanium surfaces. Lactate dehydrogenase assay determined that hLf1-11 peptide did not affect fibroblast viability. An outstanding reduction in the adhesion and early stages of biofilm formation of Streptococcus sanguinis and Lactobacillus salivarius was observed on the biofunctionalized surfaces compared to control non-treated samples. Furthermore, samples coated with the hLf1-11 peptide inhibited the early stages of bacterial growth. Thus, this strategy holds great potential to develop antimicrobial biomaterials for dental applications. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

We present a click chemistry- based molecular toolkit for the bio- functionalization of materials to selec- tively control integrin-mediated cell ad- hesion. To this end, a 5 b 1-selective RGD peptidomimetics were covalently immobilized on Ti-based materials, and the capacity to promote the selective binding of a 5 b 1 was evaluated using a solid-phase integrin binding assay. This functionalization strategy yielded surfa- ces with a nine-fold increased affinity for a 5 b 1, in comparison to control samples, and total selectivity against the binding of the closely related integ- rin a v b 3. Moreover, our methodology allowed the screening of several phos- phonic acid containing anchoring units to find the best spacer–anchor moiety required for establishing an efficient binding to titanium and to promote se- lective integrin binding. The integrin subtype specificity of these biofunc- tionalized surfaces was further exam- ined in vitro by inducing selective ad- hesion of genetically modified fibro- blasts, which express exclusively the a 5 b 1 integrin. The versatility of our molecular toolkit was proven by shift- ing the cellular specificity of the mate- rials from a 5 b 1- to a v b 3-expressing fi- broblasts by using an a v b 3-selective peptidomimetic as coating molecule. The results shown here represent the first functionalization of Ti-based mate- rials with a 5 b 1- or a v b 3-selective pep- tidomimetics that allow an unprece- dented control to discriminate between a 5 b 1- and a v b 3-mediated adhesions. The role of these two integrins in dif- ferent biological events is still a matter of debate and is frequently discussed in literature. Thus, such bioactive titanium surfaces will be of great relevance for the study of integrin-mediated cell ad- hesion and the development of new bi- omaterials targeting specific cell types

Surface modification stands out as a versatile technique to create instructive biomaterials that are able to actively direct stem cell fate. Chemical functionalization of titanium has been used in this work to stimulate the differentiation of human mesenchymal stem cells (hMSCs) into the osteoblastic lineage, by covalently anchoring a synthetic double-branched molecule (PTF) to the metal that allows a finely controlled presentation of peptidic motifs. In detail, the effect of the RGD adhesive peptide and its synergy motif PHSRN is studied, comparing a random distribution of the two peptides with the chemically-tailored disposition within the custom made synthetic platform, which mimics the interspacing between the motifs observed in fibronectin. Contact angle measurement and XPS analysis are used to prove the efficiency of functionalization. We demonstrate that, by rationally designing ligands, stem cell response can be efficiently guided towards the osteogenic phenotype: In vitro, PTF-functionalized surfaces support hMSCs adhesion, with higher cell area and formation of focal contacts, expression of the integrin receptor α5β1 and the osteogenic marker Runx2, and deposition a highly mineralized matrix, reaching values of mineralization comparable to fibronectin. Our strategy is also demonstrated to be efficient in promoting new bone growth in vivo in a rat calvarial defect. These results highlight the efficacy of chemical control over the presentation of bioactive peptides; such systems may be used to engineer bioactive surfaces with improved osseointegrative properties, or can be easily tuned to generate multi-functional coatings requiring a tailored disposition of the peptidic motifs. Statement of significance Organic coatings have been proposed as a solution to foster osseointegration of orthopedic implants. Among them, extracellular matrix-derived peptide motifs are an interesting biomimetic strategy to harness cell-surface interactions. Nonetheless, the combination of multiple peptide motifs in a controlled manner is essential to achieve receptor specificity and fully exploit the potentiality of synthetic peptides. Herein, we covalently graft to titanium a double branched molecule to guide stem cell fate in vitro and generate an osseoinductive titanium surface in vivo. Such synthetic ligand allows for the simultaneous presentation of two bioactive motifs, thus is ideal to test the effect of synergic sequences, such as RGD and PHSRN, and is a clear example of the versatility and feasibility of rationally designed biomolecules.

Intervertebral implants should be designed with low load requirements, high friction coefficient and low elastic modulus in order to avoid the stress shielding effect on bone. Furthermore, the presence of a highly interconnected porous structure allows stimulating bone in-growth and enhancing implant-bone fixation. The aim of this study was to obtain bioactive porous titanium implants with highly interconnected pores with a total porosity of approximately 57¿%. Porous Titanium implants were produced by powder sintering route using the space holder technique with a binder phase and were then evaluated in an in vivo study. The size of the interconnection diameter between the macropores was about 210¿µm in order to guarantee bone in-growth through osteblastic cell penetration. Surface roughness and mechanical properties were analyzed. Stiffness was reduced as a result of the powder sintering technique which allowed the formation of a porous network. Compression and fatigue tests exhibited suitable properties in order to guarantee a proper compromise between mechanical properties and pore interconnectivity. Bioactivity treatment effect in novel sintered porous titanium materials was studied by thermo-chemical treatments and were compared with the same material that had undergone different bioactive treatments. Bioactive thermo-chemical treatment was confirmed by the presence of sodium titanates on the surface of the implants as well as inside the porous network. Raman spectroscopy results suggested that the identified titanate structures would enhance in vivo apatite formation by promoting ion exchange for the apatite formation process. In vivo results demonstrated that the bioactive titanium achieved over 75¿% tissue colonization compared to the 40¿% value for the untreated titanium.

The aim of this work is to describe and compare mechanical properties of eight widely used nickel–titanium orthodontic wires under uniform testing conditions and to determine the influence of the heat treatments on the loss of the superelasticity. Ten archwires from two batches from eight different manufacturers were evaluated. A three-point bending test was performed, in accordance with ISO 15841:2006, on 80 round nickel–titanium archwire segments of 0.016 inch. To obtain a load-deflection curve, the centre of each segment was deflected to 3.1 mm and then unloaded until force became zero. On the unloading curve, deflection at the end of the plateau and forces delivered at that point, and at 3, 2, 1 and 0.5 mm of deflection, were recorded. Plateau slopes were calculated from 3 and from 2 mm of deflection. Data obtained were statistically analysed to determine inter-brand, intra-brand and inter-batch differences (P

Novel researches are focused on the prevention and management of post-operative infections. To avoid this common complication of implant surgery, it is preferable to use new biomaterials with antibacterial properties. Therefore, the aim of this work is to develop a method of combining the antibacterial properties of antibiotic-loaded poly(3-hydroxybutyrate) (PHB) nano- and micro-spheres and poly(ethylene glycol) (PEG) as an antifouling agent, with titanium (Ti), as the base material for implants, in order to obtain surfaces with antibacterial activity. The Ti surfaces were linked to both PHB particles and PEG by a covalent bond. This attachment was carried out by firstly activating the surfaces with either Oxygen plasma or Sodium hydroxide. Further functionalization of the activated surfaces with different alkoxysilanes allows the reaction with PHB particles and PEG. The study confirms that the Ti surfaces achieved the antibacterial properties by combining the antibiotic-loaded PHB spheres, and PEG as an antifouling agent.

It is known that surface roughness and chemical composition of the titanium surface influence the osseointegration of titanium implants. Most commercial dental implants offer a shot-blasted rough surface. It is also known that apatite layers coating the surface of titanium implants improve bone response, but the adhesion of the layer to the substrate poses some problems. In this study the roughness and adhesion strength to a titanium dental implant surface of an apatite layer deposited via wet chemistry after a thermochemical treatment were compared with those of plasma-sprayed apatite layers and machined titanium surfaces. Different surface conditions have been studied: (a) as-received machined dental implant surface; (b) grit-blasted titanium surface; (c) grit-blasted and thermochemicallytreated titanium surface; (d) titanium surfaces coated with plasma-sprayed apatite. The morphology and roughness of the samples were measured and compared. The adhesion of the apatite layers to the titanium was compared by means of a scratch test. Measured roughness showed that the deposition of an apatite layer did not affect roughness but plasmasprayed apatite produced a decrease on roughness values when compared to control samples. Both roughness and adhesion strength of the deposited apatite layer to the titanium substrate were higher than those of the plasma-sprayed apatite.

Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria-cell co-cultures.; Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. (C) 2015 Elsevier B.V. All rights reserved.

The use of tantalum as biomaterial for orthopedic applications is gaining considerable attention in the clinical practice because it presents an excellent chemical stability, body fluid resistance, biocompatibility, and it is more osteoconductive than titanium or cobalt-chromium alloys. Nonetheless, metallic biomaterials are commonly bioinert and may not provide fast and long-lasting interactions with surrounding tissues. The use of short cell adhesive peptides derived from the extracellular matrix has shown to improve cell adhesion and accelerate the implant’s biointegration in vivo. However, this strategy has been rarely applied to tantalum materials. In this work, we have studied two immobilization strategies (physical adsorption and covalent binding via silanization) to functionalize tantalum surfaces with a cell adhesive RGD peptide. Surfaces were used untreated or activated with either HNO3 or UV/ozone treatments. The process of biofunctionalization was characterized by means of physicochemical and biological methods. Physisorption of the RGD peptide on control and HNO3-treated tantalum surfaces significantly enhanced the attachment and spreading of osteoblast-like cells; however, no effect on cell adhesion was observed in ozone-treated samples. This effect was attributed to the inefficient binding of the peptide on these highly hydrophilic surfaces, as evidenced by contact angle measurements and X-ray photoelectron spectroscopy. In contrast, activation of tantalum with UV/ozone proved to be the most efficient method to support silanization and subsequent peptide attachment, displaying the highest values of cell adhesion. This study demonstrates that both physical adsorption and silanization are feasible methods to immobilize peptides onto tantalum-based materials, providing them with superior bioactivity. info:eu-repo/semantics/publishedVersion

Nowadays, one of the main challenges in metal implants for bone substitution is the achievement of an elastic modulus close to that of human cortical bone as well as to provide an adequate interaction with the surrounding tissue avoiding in vivo foreign body reaction. From this perspective, a new Ti-based alloy has been developed with Nb and Hf as alloying elements which are known as non-toxic and with good corrosion properties. The microstructure, mechanical behaviour and the physicochemical properties of this novel titanium alloy have been studied. Relationship of surface chemistry and surface electric charge with protein adsorption and cell adhesion has been evaluated due to its role for understanding the mechanism of biological interactions with tissues. The Ti25Nb21Hf alloy presented a lower elastic modulus than commercial alloys with a superior ultimate strength and yield strength than CP-Ti and very close to Ti6Al4V. It also exhibited good corrosion resistance. Furthermore, the results revealed that it had no cytotoxic effect on rat mesenchymal stem cells and allowed protein adsorption and cell adhesion. The experimental results make this alloy a promising material for bone substitution or for biomedical devices. info:eu-repo/semantics/acceptedVersion

Dental implant failure can be associated with infections that develop into peri-implantitis. In order to reduce biofilm formation, several strategies focusing on the use of antimicrobial peptides (AMPs) have been studied. To covalently immobilize these molecules onto metallic substrates, several techniques have been developed, including silanization and polymer brush prepared by surface-initiated atom transfer radical polymerization (ATRP), with varied peptide binding yield and antibacterial performance. The aim of the present study was to compare the efficiency of these methods to immobilize the lactoferrin-derived hLf1–11 antibacterial peptide onto titanium, and evaluate their antibacterial activity in vitro. Smooth titanium samples were coated with hLf1–11 peptide under three different conditions: silanization with 3-aminopropyltriethoxysilane (APTES), and polymer brush based coatings with two different silanes. Peptide presence was determined by X-ray photoelectron spectroscopy, and the mechanical stability of the coatings was studied under ultrasonication. The LDH assays confirmed that HFFs viability and proliferation were no affected by the treatments. The in vitro antibacterial properties of the modified surfaces were tested with two oral strains (Streptococcus sanguinis and Lactobacillus salivarius) showing an outstanding reduction. A higher decrease in bacterial attachment was noticed when samples were modified by ATRP methods compared to silanization. This effect is likely due to the capacity to immobilize more peptide on the surfaces using polymer brushes and the nonfouling nature of polymer PDMA segment. info:eu-repo/semantics/acceptedVersion

L’ús d’implants de titani per a traumatologia i odontologia és una pràctica molt estesa actualment. El seu èxit, però, es veu afectat pels casos de infeccions que pateixen. En el cas concret dels implants dentals, el 14% dels implants pateixen infeccions bacterianes i entre el 5 i el 8% presenten infecció bacteriana que desenvolupa una peri-implantitis i una conseqüent pèrdua de l’implant. Per aquest motiu, en els darrers anys s’ha estudiat el desenvolupament de superfícies antibacterianes. En aquest treball s’optimitza un tractament antiadherent per a superfícies de titani amb l’objectiu de minimitzar l’adhesió bacteriana que pugui produir una infecció posterior. S’ha desenvolupat un tractament de la superfície de titani per formar un recobriment amb un polímer antiadherent. S’han estudiat les característiques fisicoquímiques de la superfície que en resulta. També s’ha estudiat la seva biocompatibilitat i capacitat per evitar l’adhesió de proteïnes i bacteris. The use of titanium implants for orthopedic and dental practice is currently widespread. Its success, however, is affected by implant-related infections. In the case of dental implants, 14% of implants suffered bacterial infections and between 5 and 8% have a bacterial infection that develops peri-implantitis and consequent loss of the implant. For this reason, in the recent years the development of antibacterial surfaces has been thoroughly studied. In this paper, a treatment has been optimized for creating antifouling titanium surfaces with the objective to minimize bacterial adhesion that may result in an infection. The titanium surface treatment produces a coating with an antifouling polymer. The physicochemical characteristics of the resulting surface have been studied, as well as the biocompatibility and the ability to prevent the adhesion of proteins and bacteria.

Among all biomaterials used for bone replacement, it is recognized that both commercially pure titanium (Ti c.p.) and Ti6Al4V alloy are the materials that show the best in vivo performance due to their excellent balance between mechanical, physical-chemical and biofunctional properties. However, one of its main drawbacks, which compromise the service reliability of the implants and its osteointegration capacity, is the thin film of fibrous tissue around the implant due to the bioinert behaviour of titanium. One of the alternatives more studied to improve the titanium osteointegration is the surface modification through the control of the roughness parameters within a specific range which is recognized that improve the osteoblasts adhesion. In this work is investigated the influence of different electrochemical processing conditions for surface modification of c.p. Ti, in their microstructural, morphological, topographical and mechanical properties, as well as in their biological behaviour. The electrochemical anodizing treatment was performed by using different electrolytes based on phosphoric acid (H3PO4), sulphuric acid (H2SO4) with a fluoride salt; and the Focused Ion Beam (FIB) technique, normally named as Nanolab, was used for the microstructural, chemical and morphological characterization, as well as the confocal laser microscopy technique which also served for roughness measurements. The mechanical response of the anodic layers was evaluated through the using of a scratch tester which showed the critical loads for the coating damages. The characterization results showed that both, concentrations and electrolyte species, clearly influenced the morphological and topographical features, as well as the chemical composition of the anodic layer. By using the FIB was possible to detect nanopores within both the surface and the bulk of the coating. Some of the conditions generated a very special coating morphology which promoted a better osteoblasts adhesion. Contrary to what it was a priory expected, all anodic coatings showed high critical loads for damages during scratch test, despite their high porosity, which could be related with some defects coalescence mechanism that allows dissipating the high stress concentration applied during the test.

Dental implant failure is commonly associated to dental plaque formation. This problem starts with bacterial colonization on implant surface upon implantation. Early colonizers (such as Streptococcus sanguinis) play a key role on that process, because they attach directly to the surface and facilitate adhesion of later colonizers. Surface treatments have been focused to improve osseointegration, where shot-blasting is one of the most used. However the effects on bacterial adhesion on that sort of surfaces have not been elucidated at all. A methodological procedure to test bacterial adherence to titanium shot-blasted surfaces (alumina and silicon carbide) by quantifying bacterial detached cells per area unit, was performed. In parallel, the surface properties of samples (i.e., roughness and surface energy), were analyzed in order to assess the relationship between surface treatment and bacterial adhesion. Rather than roughness, surface energy correlated to physicochemical properties of shot-blasted particles appears as critical factors for S. sanguinis adherence to titanium surfaces.

The objective of the article is to study surface topographic changes and nickel release in lingual orthodontic archwires in vitro. Stainless steel (SS), nickel–titanium (NiTi) and copper–nickel–titanium (CuNiTi) lingual orthodontic archwires were studied using atomic absorption spectrometry for nickel release after immersion in a saline solution. Surface roughness changes were measured using atomic force microscopy. Differences between groups were analyzed using independent sample t-tests. Statistically significant changes in roughness were seen in all archwires except NiTi. Surface changes were most severe in the CuNiTi alloy. SS archwires released the highest amount of nickel. In conclusion, only roughness changes in CuNiTi archwires seemed to be clinically significant. The amount of nickel released for all archwires tested is below the levels known to cause cell damage.

Se ha obtenido una capa de fosfato de calcio del mismo contenido mineral que el hueso en la superficie del implante dental de titanio, que tiene como consecuencia una muy rápida y eficaz osteointegración. Esta capa se ha obtenido mediante un método biomimético por vía termoquímica. La capa se une al substrato por enlace químico. Este hecho evita todos los inconvenientes de los métodos de recubrimiento convencionales (plasma spray, ablación láser...) cuya unión es por interacción mecánica, lo cual provocaba que hubiese espacio vacío entre el substrato y la capa facilitando la colonización bacteriana (periimplantitis) y un desprendimiento y degradación acelerados de la misma. Con la formación de la capa por el método termoquímico, sobre la superficie rugosa del implante, el tiempo de convalecencia se reduce significativamente ya que colocamos una estructura en la superficie del implante que las células reconocen, facilitando el crecimiento óseo alrededor del implante dental. A esta capacidad de formar capas cerámicas de fosfato de calcio en la superficie del biomaterial se la conoce como bioactividad y, anteriormente, era una habilidad que sólo tenían algunas cerámicas y vidrios. El desarrollo y obtención de estos implantes de titanio con una rugosidad optimizada y bioactivos combina una magnífica fijación mecánica con la rapidez del crecimiento del hueso, con lo que se consigue un implante con mejor osteointegración tanto a corto como a largo plazo.

El éxito clínico de los implantes dentales, fabricados en titanio comercialmente puro (Ti c.p.), está basado en la consecución de la osteointegración, es decir, la conexión directa estructural y funcional entre el hueso vivo, ordenado, y la superficie del implante. La mejora de la osteointegración a corto y largo plazo es función de múltiples factores, de entre los cuales, la calidad superficial del implante (fisicoquímica y topográfica) es de gran importancia. De hecho, todas las interacciones biológicas y mecánicas que se dan entre el implante y los tejidos circundantes son a través de la interfaz creada entre dichos tejidos y la superficie del material implantado.En este trabajo se estudian y desarrollan distintos tratamientos aplicados sobre la superficie de los implantes dentales con el objetivo final de obtener implantes con una mejor osteointegración, tanto a corto como a largo plazo. En la primera parte se obtienen superficies rugosas por medio del tratamiento del granallado.La rugosidad de las superficies de Ti c.p. granalladas depende no sólo del tamaño de las partículas abrasivas de proyección empleadas (125 - 300 m; 425 - 600 m; 1000 - 1400 m), sino también de su naturaleza química (Al2O3, SiC, TiO2 y ZrO2) y su forma. Esta rugosidad se debe cuantificar con, al menos, dos parámetros, uno de altura (Ra) y otro de espaciado (Pc). Además, cualquiera que sea la naturaleza química de las partículas empleadas, quedan restos de las mismas sobre las superficies tratadas. Con estas premisas, las propiedades de la superficie del Ti c.p. granallado se han podido optimizar, ya que la respuesta de adhesión y diferenciación de los osteoblastos está influenciada por la rugosidad y la naturaleza de las partículas de proyección. Además, aunque el aumento de rugosidad y las tensiones residuales que se inducen con el granallado influyen sobre el comportamiento electroquímico del material, éste es adecuado con respecto a su resistencia a la corrosión, de acuerdo a su posible utilización como material para la fabricación de implantes dentales.En la segunda parte se obtienen superficies rugosas y bioactivas por medio de un tratamiento en dos pasos: en primer lugar se granalla el implante (con las condiciones óptimas determinadas en la primera parte); y después se aplica un tratamiento termoquímico. El tratamiento termoquímico consiste en atacar el metal con NaOH y obtener en su superficie un gel hidratado de titanato de sodio. Este gel se deshidrata y densifica con un tratamiento térmico a 600 oC. En estas condiciones, el Ti c.p. es bioactivo.Las superficies de Ti c.p. granalladas con Al2O3 y tratadas termoquímicamente, demuestran su potencial bioactividad porque hacen crecer por vía química in vitro, sobre su superficie, una capa de apatita; y la confirman, al crecer también in vivo. Sin embargo, la presencia de los restos de partículas de SiC sobre la superficie del metal inhibe su bioactividad. Estas superficies rugosas y bioactivas se estudian de forma comparativa, in vitro e in vivo, con otras no rugosas y/o bioinertes. La respuesta de diferenciación de los osteoblastos y la osteointegración a corto y medio plazo se ven favorecidas por la combinación sinérgica de la rugosidad y la bioatividad del metal. Como consecuencia, los implantes rugosos y bioactivos son candidatos preferenciales para ser utilizados en los procedimientos clínicos de carga inmediata.

Se han estudiado los endurecimientos superficiales que se producen en la aleación Ti 6Al 4V, mediante los procesos de anodización electroquímica y mediante diferentes tratamientos térmicos a distintas microestructuras de dicha aleación, así como los procesos de nitruración mediante difusión gaseosa.. Los resultados de la combinación de la anodización y los tratamientos térmicos producen endurecimientos superiores a 1000 HV lo que mejorará la resistencia al desgaste de estas aleaciones en sus aplicaciones para prótesis articulares. Mejores resultados ofrecen los valores de nitruración que pueden alcanzar las 1400 unidades Vickers.

Se ha demostrado que realizar el tratamiento de granallado sobre implantes mejora la fijación de los mismos, debido a la rugosidad superficial que adquieren. Variando el tamaño de las partículas de proyección del granallado, se varía el valor de rugosidad. Por otra parte, siempre quedan partículas adheridas en la superficie del implante, lo cual puede tener influencia en distintas propiedades, entre las cuales cabe destacar su resistencia a la corrosión. Este estudio determina el comportamiento a la corrosión, mediante mediciones potenciodinámicas, del titanio comercialmente puro granallado con diferentes materiales de partículas de proyección (Al2O3 y SiC) y con diferentes tamaños de partícula (200, 600 y 900 mm). La rugosidad no tuvo influencia significativa en los resultados de corrosión, pero sí la tuvo la naturaleza de las partículas de proyección. Así, los discos tratados con SiC, debido a la oxidación de estas partículas adheridas en la superficie del titanio, presentaron densidades de corriente un orden de magnitud mayores que los discos tratados con Al2O3, lo que les confiere peores características de resistencia a la corrosión. No obstante, todos los discos presentaron un adecuado comportamiento frente a la corrosión.

El objetivo de este trabajo de investigación es la obtención de una capa de anodizado, que sea homogénea en toda la superficie del implante de titanio. Esta capa de óxido de titanio tendrá unas propiedades beneficiosas para el implante dental como son: 1. Limpieza de residuos tanto orgánicos como inorgánicos de la superficie del implante. 2. Mejora de la resistencia a la corrosión del implante. 3. Disminución de la liberación de iones del titanio al medio fisiológico. 4. Aumento de la dureza superficial así como de la resistencia al desgaste.

Puesto que en los momentos actuales se está usando el titanio de manera habitual como componente de todas las endoprótesis, y de manera cada vez más importante se está incluyendo en la fabricación de los implantes de osteosíntesis y estabilización osteoarticular, es necesario que los cirujanos ortopédicos nos acerquemos al conocimiento de sus bondades o de sus inconvenientes. Tratamos por ello de situarlo en sus coordenadas de aplicación clínica, resaltando sus virtudes en los aspectos biomecánicos, en las garantías de biocompatibilidad que permiten que se pueda realizar por parte del hueso receptor el fenómeno de la osteointegración, y en general en la respuesta del huésped ante este metal no desde el punto de vista de la unión al mismo, sino de las reacciones adversas o no, que pueda ocasionar sistémica o localmente. Desde el punto de vista biomecánico, su ductilidad y resistencia y su gran capacidad de autorreparación por el mecanismo de la pasivación inmediata anulando por tanto el fenómeno corrosivo, son sus mejores credenciales. Biológicamente, su compatibilidad con el medio que lo recibe permitiendo el crecimiento hístico a su alrededor sin interferirlo, junto a su baja o nula capacidad de reacción a cuerpo extraño y mucho menos en la producción de fenómenos de sensibilidad son las otras características que avalan su uso. Como material endoprotésico, junto a indudables constataciones clínicas y de laboratorio que le sitúan como el mejor metal proosteointegración, otras tratan de encontrar sombras para su empleo.

A novel class of polyurethane-polyurea nanoparticles (PUUa NPs) to install multifunctionality on biomaterials is presented. Biofunctionalization of titanium with roxithromycin loaded RGD-decorated PUUa NPs results in an outstanding improvement of osteoblast adhesion and strong suppression of bacterial attachment. This strategy represents a powerful approach to enhance the osseointegration of implant materials. info:eu-repo/semantics/acceptedVersion

Titanium dental implants are commonly used for the replacement of lost teeth, but they present a considerable number of failures due to the infection on surrounding tissues. The aim of this paper is the development of a polyethylene glycol-like (PEG-like) coating on the titanium surface by plasma polymerization to obtain a novel improved surface with suitable low bacterial adhesion and adequate cell response. Surface analysis data of these coatings are presented, in particular, water contact angle, surface roughness, and film chemistry, demonstrating the presence of a PEG-like coating. Streptococcus sanguinis and Lactobacillus salivarius bacterial adhesion assays showed a decreased adhesion on the plasma polymerized samples, while cell adhesion of fibroblasts and osteoblasts on the treated surfaces was similar to control surfaces. Thus, the PEG-like antifouling coating obtained by plasma polymerization on Ti confers this biomaterial's highly suitable properties for dental applications, as they reduce the possibility of infection while allowing the tissue integration around the implant. (C) 2015 American Vacuum Society.

This study shows the potential risk of microfiltration between two different types of implant-abutment connections screwed at 45 Ncm: external and internal. For the first time the use of a mechanical artificial mouth is used with the values (compression and torsion loads with a frequency of 2 Hz) of the human chewing. The mechanical tests were performed with an artificial saliva at 37 degrees C. The microgap in the connection was measured by an Image Analysis software incorporated in a high resolution scanning electron microscopy. Implant connections were filled with methylene blue by using self-adjustable precision pipettes and the quantity of leakage was determined by high sensitivity spectometry. We showed that the internal connection has lower microgaps compared to the external ones and these microgaps increased with the number of mechanical cycles. The leakage of methylene blue was higher when the external connection was performed. Microgaps and the influence of the mechanical loads are very important for the long-term behavior avoiding the bacteria colonization in the dental implants. These aspects should be known by the implantologists. info:eu-repo/semantics/acceptedVersion