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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.

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.

L’objecte principal és fabricar pròtesis cranials utilitzant el mètode de deformació incremental de xapa (ISF) amb materials polímers biocompatibles i estudiar-ne el resultat final. Per aconseguir-ho es faran comparacions amb les metodologies SPIF i TPIF utilitzant unes geometries de referència per, posteriorment, trobar els millors paràmetres amb els que fabricar les pròtesis. Es farà ús d’informació de projectes anteriors i s’adaptaran els resultats trobats per aquest projecte

El GREP és un grup de recerca en enginyeria de procés, producte i producció vinculat a la Universitat de Girona. Des de fa uns anys, s’està treballant en el desenvolupament i la investigació de dispositius mèdics biocompatibles mitjançant les noves tecnologies de fabricació. En aquest aspecte, membres del departament han fet un viatge a Brasil per investigar sobre les lesions a la mandíbula i quins són els dispositius que s’utilitzen actualment per fer front a les lesions de la regió maxil•lofacial. A partir d’aquí neix la idea de començar a treballar en el desenvolupament d’un disseny de placa per a osteosíntesi, és a dir, un dispositiu que ajudi en la reconstrucció de la zona de la mandíbula afectada actuant de manera similar a una pròtesi, però que un cop superada la lesió s’ha d’extreure mitjançant una segona intervenció quirúrgica. Les línies d’estudi del projecte seran dues, ben definides: - Disseny de la placa: un cop estudiat el cas en concret i analitzades les solucions comercials existents al mercat, després de fer un anàlisis funcional complet, es pretén aportar nous dissenys i escollir la millor solució que integri tots els - Viabilitat de la biocompatibilitat de materials: es farà una selecció de materials metàl•lics i polimèrics amb la fi de comparar-ne les seves propietats i estudiar la possibilitat d’incorporar material polimèric bioabsorbible en l’estructura mallada de reforç

The titanium alloys used in orthopaedic and dental implants are corrosion-resistant and compatible with the human body due to the titanium oxid film which forms spontaneously on the implant surface. However, the utilization of more than one type of alloy or metal on the same patient and the fragility and the thin thickness of the oxid layer, can give rise to the appearance of the corossion phenomena and/or ion release. It is well known that enough concentration of metallic particles are toxic, and are able to produce lnflammation, allergy genetic mutations or carcinogenic processes. With the purpose of minimize the corrossion in the implants and the metallic ion release to the physiological environment it is possible to grow up the titanium oxid layer in a controlled way to have a tough, homogeneous and stable layer with the anodization technique. In this work it is evaluated the improvements in corrosion resistance and the decrease of the metallic ion release due to the anodized layer.

The titanium alloys used in orthopaedic and dental implants are corrosion-resistant and compatible with the human body due to the titanium oxid film which forms spontaneously on the implant surface. However, the utilization of more than one type of alloy or metal on the same patient and the fragility and the thin thickness of the oxid layer, can give rise to the appearance of the corossion phenomena and/or ion release. It is well known that enough concentration of metallic particles are toxic, and are able to produce lnflammation, allergy genetic mutations or carcinogenic processes. With the purpose of minimize the corrossion in the implants and the metallic ion release to the physiological environment it is possible to grow up the titanium oxid layer in a controlled way to have a tough, homogeneous and stable layer with the anodization technique. In this work it is evaluated the improvements in corrosion resistance and the decrease of the metallic ion release due to the anodized layer.