Y. Torres

• PhD. Full Professor
• Professor (Full) at University of Seville

“Scientific Advances in STEM: Synergies to Achieve Success, Volume 3” emphasizes the importance of interdisciplinary collaboration in Science, Technology, Engineering, and Mathematics (STEM) for driving innovation and societal benefits [...]

Conventional drug delivery approaches, including tablets and capsules, often suffer from reduced therapeutic effectiveness, largely attributed to inadequate bioavailability and difficulties in ensuring patient adherence. These challenges have driven the development of advanced drug delivery systems (DDS), with hydrogels and especially nanogels emer...

High entropy alloys (HEAs) are potential materials for biomedical applications due to their unique properties. Also, the use of functionally graded porous materials (FGPM) presents an interesting approach that could help to decrease the Young’s modulus while simultaneously mimicking highly hierarchical porosity of the bone structure. In this study,...

Early implant failure and bone resorption may occur in load-bearing conditions as a result of stress shielding brought on by a mismatch in the bone-Ti-implant modulus. A review with a novel multidisciplinary perspective is proposed in this work, which considers recent developments of β-Titanium alloys and new trends in novel microstructures, proces...

Commercially pure titanium (c.p. Ti) and Ti6Al4V alloys are the most widely used metallic biomaterials in the biomedical sector. However, their high rigidity and the controversial toxicity of their alloying elements often compromise their clinical success. The use of porous β‐Titanium alloys is proposed as a solution to these issues. In this regard...

Springer Proceedings in Materials publishes the latest research in Materials Science and Engineering presented at high standard academic conferences and scientific meetings. The scope is multidisciplinary and ranges from fundamental to applied research, including, but not limited to: • Structural Materials • Metallic Materials • Magnetic, Optical a...

Macroporous titanium structures are of interest in bone reconstruction because of their reduced modulus of elasticity (compared to bulk titanium), possibility of being colonized by cells, and biocompatibility. However, they are not bioactive and are not able to actively facilitate bone ingrowth or reduce bacterial adhesion. In the present research,...

In the quest for advancing the performance of metallic implants, surface modification emerges as a pivotal strategy to mitigate ion depletion, enhance the host's biological response, and exhibit anti-microbial behavior with reduced cytotoxicity. In this study, we developed a non-traditional electrophoretic deposition (EPD) hybrid coating for medica...

Bone resorption and possible fracture of host tissue are some consequences resulting from the mismatch between the Young's Modulus of the constituent materials of implants and bone that compromises the reliability of implants for replacing damaged bone tissue. The use of functional graded porous materials presents an interesting approach that could...

The biomechanical performance of dental implants determines their clinical success. In this work, the stress and deformation distribution of a new implant design (dense and porous) was evaluated by the Finite Element Method. Furthermore, the effect of the location of the dental implant in the maxillary zone, as well as the mechanical response in th...

In industries as diverse as automotive, aerospace, medical, energy, construction, electronics, and food, the engineering technology known as 3D printing or additive manufacturing facilitates the fabrication of rapid prototypes and the delivery of customized parts. This article explores recent advancements and emerging trends in 3D printing from a n...

This research work proposes a synergistic approach to improve implants' performance through the use of porous Ti substrates to reduce the mismatch between Young's modulus of Ti (around 110 GPa) and the cortical bone (20-25 GPa), and the application of a biodegradable, acrylic acid-based polymeric coating to reduce bacterial adhesion and proliferati...

The thermal stability and degradation, near-to-surface mechanical properties, and scratch resistance and damage mechanism of poly(etheretherketone) (PEEK)/reduced graphene oxide (RGO) nanocomposite coatings are analyzed and discussed in terms of their nanosheet content and microstructure. Although RGO modified the thermal stability and degradation...

Stress shielding and osseointegration are two main challenges in bone regeneration, which have been targeted successfully by chemical and physical surface modification methods. Direct irradiation synthesis (DIS) is an energetic ion irradiation method that generates self-organized nanopatterns conformal to the surface of materials with complex geome...

TiNbZrTa Porous materials Powder metallurgy Tribomechanical behavior a b s t r a c t The use of b-Titanium alloys to fabricate metal implants with Young's modulus that resembles bone tissues is presented as an alternative to commercially pure titanium or a-Titanium alloys, although it is still necessary to introduce proper implant porosity to reach...

This work proposes an innovative strategy that combines two well-known easy and economical preparation techniques: powder metallurgy based space-holder (SH) technique to provide porous biocom-patible Ti substrates with balanced biomechanical behavior (for cortical bone tissue substitution) promoting bone ingrowth and biocoating infiltration, and el...

Tooth loss is common in patients struggling with dental cavities, periodontal diseases, and tumors, as well as those who abuse tobacco or drugs. In this scenario, dental implants have become the primary treatment option for complete or partial tooth loss. Dental implant failure can be caused by stress shielding phenomenon, poor osseointegration, or...

The spread of antibiotic resistance among human and animal pathogens is one of the more significant public health concerns. Moreover, the restrictions on the use of particular antibiotics can limit the options for the treatment of infections in veterinary clinical practice. In this context, searching for alternative antimicrobial substances is cruc...

Teeth loss due to periodontal diseases, trauma, or infections often causes dimensional loss in the affected maxillary. In patients with reduced maxillary size, restoration of chewing function and esthetics with endosseous dental implants may fail. The aim of this work was to simulate the biomechanical behavior, using the finite element method, of c...

Articular cartilage (AC) has a low ability for endogenous repair, and current treatments are not completely efficient in generating strong and healthy repair tissue. As a result, there is a great deal of interest in cartilage repair and recovery of joint function due to the aging population and the increasing frequency of cartilage degradation and...

Articular cartilage (AC) has a low ability for endogenous repair, and current treatments are not completely efficient in generating strong and healthy repair tissue. As a result, there is a great deal of interest in cartilage repair and recovery of joint function due to the aging population and the increasing frequency of cartilage degradation and...

Despite the increasing progress achieved in the last 20 years in both the fabrication of porous dental implants and the development of new biopolymers for targeting drug therapy, there are important issues such as bone resorption, poor osseointegration, and bacterial infections that remain as critical challenges to avoid clinical failure problems....

In this work, the fatigue and cellular performance of novel superficially treated porous titanium dental implants made up using conventional powder metallurgy and space-holder techniques (30 vol.% and 50 vol.%, both with a spacer size range of 100-200 µm) are evaluated. Before the sintering stage, a specific stage of CNC milling of the screw thread...

Stress shielding phenomenon, poor osseointegration, or bacterial infections of titanium dental implants are widely recognized as key problems that deeply affect their survival rate. In this work, a joint solution to solve these three limitations is proposed. The first two issues were minimized applying porous Ti samples. This sub-strate exhibits an...

Bone resorption and inadequate osseointegration are considered the main problems of titanium implants. In this investigation, the texture and surface roughness of porous titanium samples obtained by the space holder technique were modified with a femtosecond Yb-doped fiber laser. Different percentages of porosity (30, 40, 50, and 60 vol.%) and part...

In this research work, the fabrication of biphasic composite implants has been investigated. Porous, commercially available pure Ti (50 vol % porosity and pore distributions of 100-200, 250-355, and 355-500 μm) has been used as a cortical bone replacement, while different composites based on a polymer blend (gelatin and alginate) and bioactive glas...

The effect of the chemical composition on the morphology and microstructure of poly(ether ether ketone) (PEEK)/reduced graphene oxide (RGO) nanocomposite coatings is analyzed. RGO induced three main morphological features in the nanocomposites: (i) a large-scale co-continuous morphology related to nanosheets whose basal planes were mainly aligned w...

The use of porous titanium samples fabricated by space-holder powder metallurgy with bioactive coatings has already been reported to prevent resorption of the bone surrounding the implant and improve osseointegration, respectively. However, the presence of pores as well as the poor adherence and the brittle behavior inherent to glassy coatings affe...

Biofortification has been widely used to increase mineral nutrients in staple foods, such as wheat (Triticum aestivum). In this study, a new approach has been used by analyzing the effect of inoculation with a plant growth-promoting rhizobacterium (PGPR), namely, Bacillus aryabhattai RSO25 and the addition of 1% (v/v) of organometallic Fe-containin...

The chemical composition and surface topography of titanium implants are essential to improve implant osseointegration. The present work studies a non-invasive alternative of electrical impedance spectroscopy for the characterization of the macroporosity inherent to the manufacturing process and the effect of the surface treatment with femtosecond...

Commercially pure (c.p.) titanium grade IV with a bimodal microstructure is a promising material for biomedical implants. The influence of the processing parameters on the physical, microstructural, and mechanical properties was investigated. The bimodal microstructure was achieved from the blends of powder particles with different sizes, while the...

Porous titanium implants can be a good solution to solve the stress shielding phenomenon. However, the presence of pores compromises mechanical and corrosion resistance. In this work, porous titanium samples obtained using a space-holder technique are coated with Chitosan, Chitosan/AgNPs and Chitosan/Hydroxyapatite using only one step and an econom...

Universities should generate and relay knowledge and, therefore, placing it at the service of society. In this context, the Higher Polytechnic School (Escuela Polit´ecnica Superior, EPS) of the University of Seville (US), Spain, with a great tradition in the industrial work, aims to train the students both as professional and researcher, promoting...

In this work, the surface of porous titanium samples obtained by the space-holder technique were treated with a femtosecond laser to improve their osseointegration. Instrumented micro-indentation and scratch test were implemented to evaluate the tribo-mechanical behaviour of the surface of the modified samples. A detailed study of micro-hardness, s...

In this work porous commercially pure Ti substrates fabricated by spacer-holder technique (50 vol.% NH4HCO3 and three range pores sizes, 100 – 200 μm, 250 – 355 μm and 355 – 500 μm) were coated with two types of gelatinous materials, one as a linear polymer (non-crosslinked) and another one crosslinked. The role of the crosslink, as well as the mor...

Ti prosthesis have shown better biological compatibility, mechanical performance, and resistance to corrosion in cases of bone replacements. Nevertheless, fully dense Ti in connection with bone-host tissues show stress-shielding phenomenon that, together with the development of frequent undesirable microbial infections, may lead to implant failures...

One of the major limitations during titanium (Ti) implant osseointegration is the poor cellular interactions at the biointerface. In the present study, the combined effect of recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) and nanopatterned Ti6Al4V fabricated with Directed irradiation synthesis (DIS) is investigated in vitro. This environm...

Stress-shielding and loosening compromise the success of dental implants under real-life service conditions. This work evaluates the mechanical behavior of superficially modified porous titanium dental implants fabricated by two different routes: conventional powder-metallurgy and space-holder techniques. A novel, feasible and repetitive protocol o...

Ti6Al4V samples, obtained by selective laser melting (SLM), were subjected to successive treatments: acid etching, chemical oxidation in hydrogen peroxide solution and thermochemical processing. The effect of temperature and time of acid etching on the surface roughness, morphology, topography and chemical and phase composition after the thermochem...

Ti implants are highly biocompatible and allow orderly bone growth but, unfortunately, in the first five years after implantation, 5–10% of them fail due to poor osseointegration and to the presence of bacterial infections in prosthesis. Silver nanoparticles have been described to damage bacterial cell via prolonged release of Ag+ ions as a mode of...

Ti6Al4V samples obtained by selective laser melting were subjected to acid treatment, chemical oxidation in hydrogen peroxide solution and subsequent thermochemical treatment. The effect of temperature and time of acid etching of Ti6Al4V samples on surface roughness, morphology, topography and chemical and phase composition after the thermochemical...

In this work, the mechanical and bio-functional behavior of a TiNbTa alloy is evaluated as a potential prosthetic biomaterial used for cortical bone replacement. The results are compared with the reference Ti c.p. used as biomaterials for bone-replacement implants. The estimated mechanical behavior for TiNbTa foams was also compared with the experi...

In this study, the best equilibrium among adherence, micro-mechanical properties and coating bioactivity of bioactive glasses (45S5 and 1393) on porous titanium substrates has been explored and their potential uses for bone tissue implants. Porous titanium discs with different porosities (30 and 60 vol.%) and pore size distributions (100–200 and 35...

The design of bone implants with proper biological and mechanical properties remains a challenge in medical implantology. The use of bioactive coatings has been shown to improve the biocompatibility of the implant surface. In this study, a new approach including porous scaffolds, β-Ti alloys and nanocoatings to design new bone implants is presented...

Porous titanium substrates coated by dripping-sedimentation technique with a novel bilayer of (45S5 / 1393) bioactive glasses are proposed to overcome some limitations of the use of titanium for implants, such as the stress shielding and the poor osseointegration. Composition, thickness, roughness and micromechanical behavior (P-h curves) of the co...

Objetivos Los implantes óseos son utilizados cada vez con mayor frecuencia en la práctica clínica y, entre los materiales, el Ti o sus aleaciones son los de mejor rendimiento por sus propiedades fisicoquímicas. Aleaciones como TiNbTa han demostrado mejorar las características biomecánicas del Ti puro comercial (c.p.), sin embargo, su capacidad oste...

The use of titanium implants with adequate porosity (content, size and morphology) could solve the stress shielding limitations that occur in conventional titanium implants. Experiments to assess the cellular response (adhesion, proliferation and di�erentiation of osteoblasts) on implants are expensive, time-consuming and delicate. In this work, we...

Porous titanium is a metallic biomaterial with good properties for the clinical repair of cortical bone tissue, although the presence of pores can compromise its mechanical behavior and clinical use. It is therefore necessary to characterize the implant pore size and distribution in a suitable way. In this work, we explore the new use of electrical...

Porous substrates of commercially pure titanium have been coated with a novel bilayer of bioactive glasses, 45S5 and 1393, to improve the osseointegration and solve the stress shielding phenomenon of titanium partial implants. The porosity of the substrates, the scratch resistance and bioactivity of the coating have been evaluated. Results are disc...

The failure of titanium implants is associated with two main problems that include the bone resorption and fracture of the surrounding bone tissue (stiffness incompatibility) and implant loosening (poor osseointegration). The development of porous titanium implants with low Young modulus solve the stress shielding phenomenon, while the modification...

Magnetic composites of soft magnetic FeGa particles embedded in a silicone matrix have been synthesized. The Villari effect has been studied depending on the size and concentration of the particles and on the magnetic state of the composite. The results indicate a decrease in the Villari effect when the concentration of the magnetic particles incre...

A great variety of powder metallurgy techniques can produce biomimetic porous titanium structures with similar mechanical properties to host bone tissue. In this work, loose sintering and space holder techniques, two frequently used metallurgical techniques, are compared to evaluate the influences of porosity (content, size, morphology and wall rou...

In this work, the effect of the test configuration and temperature on the mechanical behaviour of cemented carbides (WC-Co) with different carbide grain sizes (dWC) and cobalt volume fractions (VCo), implying different binder mean free paths (λCo), was studied. The mechanical strength was measured at 600 °C with bar-shaped specimens subjected to un...

In this work, a sequential compaction device has been successfully developed and implemented to produce commercially pure titanium cylinders, in which the porosity increases from the core to the surface or vice versa. The radial graded porosity (three concentric layers) have been obtained by conventional powder-metallurgy (PM) route and/or space-ho...

The discrepancy between the stiffness of commercially pure titanium and cortical bone tissue compromises its success as a biomaterial. The use of porous titanium has been widely studied, however, it is still challenging to obtain materials able to replicate the porous structure of the bones (content, size, morphology and distribution). In this work...

For the design of smart titanium implants, it is essential to balance the surface properties without any detrimental effect on the bulk properties of the material. Therefore, in this study, an irradiation-driven surface modification called directed irradiation synthesis (DIS) has been developed to nanopattern porous and “as-received” c.p. Ti surfac...

In the present work, the use of porous titanium is proposed as a solution to the difference in stiffness between the implant and bone tissue, avoiding the bone resorption. Conventional powder metallurgical technique is an industrially established route for fabrication of this type of materials. The results are discussed in terms of the influence of...

This paper presents the results of the Villari effect study in FeGa magnetorheological composites with very low stresses. The composites consist of a silicone matrix and Fe75Ga25 powder of size ranging from 50 to 100 \(\upmu \hbox {m}\). Two types of composites, one is with 45 wt% and the other one with 30 wt% of Fe75Ga25 powder have been manufactu...

Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the sti_ness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this di_erence in sti_ness but compromise biomechanical behav...

Here, titanium porous substrates were fabricated by a space holder technique. The relationship between microstructural characteristics (pore equivalent diameter, mean free-path between pores, roughness and contact surface), mechanical properties (Young’s modulus, yield strength and dynamic micro-hardness) and bacterial behavior are discussed. The b...

The simulation of the electrical resistance sintering (ERS) of hardmetal powders has been studied. The ERS process can produce a quick consolidation of electrical conductive powders by the simultaneous application of pressure and electrical current. A model of the process has been developed, integrating three actions, namely, thermal, mechanical an...

In this work, the influence of the remnant magnetization, size distribution and content of soft magnetic reinforcement in micro-mechanical behavior of polymer matrix composites (Fe81Ga19/silicone) are evaluated. Melt spinning ribbons were pulverized in a planetary milling machine to act as composite particle reinforcement. The instrumented microind...

Polyurethanes (PU) foams with titanium particles (Ti) were prepared with castor oil (CO) and isophorone diisocyanate (IPDI) as polymeric matrix, and 1, 3 and 5 wt.% of Ti. Composites were physicochemically and mechanically characterized and their biocompatibility assessed using human dental pulp stem cells (HDPSC). PU synthesis was confirmed by FTI...

Titanium implant failures are mainly related to stress shielding phenomenon and the poor cell interaction with host bone tissue. The development of bioactive and biomimetic Ti scaffolds for bone regeneration remains a challenge which needs the design of Ti implants with enhanced osseointegration. In this context, 4 types of titanium samples were fa...

Processing metallic powders by electrical resistance sintering requires the use of insulating ceramics dies. Selecting the appropriate ceramic material according to the electrical, thermal and mechanical properties is a need. Dies produced with several ceramic materials have been tested during the production of cemented carbide in order to check th...

Titanium and its alloys are reference materials in biomedical applications because of their desirable properties. However, one of the most important concerns in long-term prostheses is bone resorption as a result of the stress-shielding phenomena. Development of porous titanium for implants with a low Young’s modulus has accomplished increasing sci...

Cemented carbide is a hard composite material widely used in a variety of industries. The global tungsten carbide market, by value, is expected to grow 4.4% (compound annual growth rate) from 2017 to 2022. One of the main markets is metal cutting and wear parts, where small bits or inserts, a few grams in weight are used. FAST technologies allow pr...