F Javier Gil

University of Murcia, Murcia, Murcia, Spain

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Publications (21)55.4 Total impact

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    ABSTRACT: The aim of this study was to determine the antibacterial properties of silver-doped titanium surfaces prepared with a novel electrochemical anodizing process.
    Clinical Oral Implants Research 05/2014; · 3.43 Impact Factor
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    ABSTRACT: Bacterial infection represents a major cause of implant failure in dentistry. A common approach to overcome this issue and treat peri-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.
    Acta biomaterialia 04/2014; · 5.68 Impact Factor
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    ABSTRACT: Objective: This study focuses on the fatigue behavior of titanium dental implants as-received, with a grit-blasted surface and with a new bioactive surface treatment (2Steps).Background: The 2Step process consists of (1) an initial grit-blasting process to produce a micro-rough surface, followed by (2) a combined thermo-chemical treatment that produces a potentially bioactive surface, that is, that can form an apatitic layer when exposed to biomimetic conditions in vitro. The 2Step treatment produced micro-rough and apatitic coating implants.Methods: Residual stresses were determined by means of X-ray diffraction. The fatigue tests were carried out at 37°C on 500 dental implants, and the S-N curve was determined. The fatigue-crack nucleation for the different treatments was analyzed.Results: The fatigue tests show that the grit-blasting process improves the fatigue life. This is a consequence of the layer of compressive residual stresses that the treatment generates in titanium surfaces. Dental implants that had its surfaced prepared with the 2Step procedure (grit-blasting and thermo-chemical treatment) had its fatigue life decreased by 10% due to the incorporation of oxygen to the surface and the relaxation of the compressive residual stress produced by the heat treatment.Conclusions: Thermo-chemical treatment is an excellent compromise between the improvement of bioactive and mechanical long-life behaviors.
    Clinical Implant Dentistry and Related Research 04/2014; 16(2). · 3.82 Impact Factor
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    ABSTRACT: Biofunctionalization of metallic materials with cell adhesive molecules derived from the extracellular matrix is a feasible approach to improve cell-material interactions and enhance the biointegration of implant materials (e.g. osseointegration of bone implants). However, classical biomimetic strategies may prove insufficient to elicit complex and multiple biological signals required in the processes of tissue regeneration. Thus, newer strategies are focusing on installing multifunctionality on biomaterials. In this work, we introduce a novel peptide-based divalent platform with the capacity to simultaneously present distinct bioactive peptide motifs in a chemically controlled fashion. As a proof of concept, the integrin-binding sequences RGD and PHSRN were selected and introduced in the platform. The biofunctionalization of titanium with this platform showed a positive trend towards increased numbers of cell attachment, and statistically higher values of spreading and proliferation of osteoblast-like cells compared to control non-coated samples. Moreover, it displayed statistically comparable or improved cell responses compared to samples coated with the single peptides or with an equimolar mixture of the two motifs. Osteoblast-like cells produced higher levels of alkaline phosphatase on surfaces functionalized with the platform than on control titanium; however, these values were not statistically significant. This study demonstrates that these peptidic structures are versatile tools to convey multiple biofunctionality to biomaterials in a chemically defined manner.
    ACS Applied Materials & Interfaces 03/2014; · 5.90 Impact Factor
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    ABSTRACT: Twenty orthodontic archwires with 55.2 % Ni and 44.8 % Ti (% weight) were subjected to a dipping treatment to coat the NiTi surface by a polyamide polymer. It has been selected a Polyamide 11 due to its remarkable long lasting performance. The transformation temperatures as well as the transformation stresses of the NiTi alloy were determined in order to know whether the coating process can alter its properties. The adhesive wear tests have been demonstrated that the wear rates as well as the dynamic friction coefficients μ of polymer coated wires are much lower than metallic wires. The corrosion studies have shown that the use of this polymer, as coating, seals the NiTi surface to prevent corrosion and the release of nickel ions. The average decrease of Ni ions release due to this coating is around 85 %.
    Journal of Materials Science Materials in Medicine 02/2014; 25(2):555-560. · 2.14 Impact Factor
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    ABSTRACT: A new thermoplastic polymer for orthodontic applications was obtained and extruded into wires with round and rectangular cross sections. We evaluated the potential of new aesthetic archwire: tensile, three point bending, friction and stress relaxation behaviour, and formability characteristics were assessed. Stresses delivered were generally slightly lower than typical beta-titanium and nickel-titanium archwires. The polymer wire has good instantaneous mechanical properties; tensile stress decayed about 2% over 2 h depending on the initial stress relaxation for up to 120 h. High formability allowed shape bending similar to that associated with stainless steel wires. The friction coefficients were lower than the metallic conventional archwires improving the slipping with the brackets. This new polymer could be a good candidate for aesthetic orthodontic archwires.
    Materials Science and Engineering: C. 01/2014; 42:1–6.
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    ABSTRACT: This study investigated the effect of two different activation methods on the surface chemical composition of a CoCrMo-alloy. The activation was performed with oxygen plasma (OP) or nitric acid (NA). The surface physical-chemical properties were thoroughly characterized by means of several analytical techniques: X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), zinc-complex substitution technique, contact angle, and interferometry. The surface modification was evaluated by assessing contamination removal, the "active" hydroxyl groups (OH-act) present at the surface, the metal oxide ratio (CoyO x (-) /CryO x (-) ) and changes in the chemical composition and topography of the oxide layer. XPS experimental data showed for both methods (OP and NA) a significant decrease of the carbon contents (C 1s) associated with contaminants and at the same time changes in the atomic composition of the oxide layer (O 1s). In addition, the O 1s XPS spectra showed differences between the percentage of OH(-) before and after OP or NA treatment, leading to the conclusion that both methods are effective for surface "cleaning" and activation. These results were further investigated and corroborated by ToF-SIMS analysis and zinc complex substitution technique. The general conclusion was that NA is more efficient in terms of contaminants removal and generation of accessible OH-act present at the surface and without altering the native metal oxide ratio (CoyO x (-) /CryO x (-) ) considered to be essential for biocompatibility.
    Journal of Materials Science Materials in Medicine 11/2013; · 2.14 Impact Factor
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    ABSTRACT: We present the immobilization on synthetic substrates of elastin-like recombinamers (ELR) that combine a bioactive motif for cell adhesion with protein antifouling properties. Physical adsorption of the recombinamers and covalent-grafting through organosilane chemistry were investigated. The biochemically-modified surfaces were thoroughly characterized and tested for protein absorption in serum by fluorescence-labelling, XPS, Ellipsometry, and OWLS. The ELR were successfully grafted and stable, even upon mechanical stresses; being the covalent bonding favourable over physical adsorption. The coated metal surfaces exhibited excellent reduction of serum protein adsorption (9ng/cm(2)) compared to the bare metal surface (310ng/cm(2)). Non-specific protein adsorption may mask the introduced bioactive motifs; therefore, the bioactivated surfaces should display serum-protein antifouling properties. Finally, improved hMSCs response was assessed on the bioactivated substrates. In summary, the coatings simultaneously displayed anti-fouling and bioactive properties. These studies investigated key factors to enhance tissue material interactions fundamental for the design of bioactive devices and future biomedical applications.
    Colloids and surfaces B: Biointerfaces 10/2013; 114C:225-233. · 4.28 Impact Factor
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    ABSTRACT: OBJECTIVES: The main purpose of this work was to assess the short-term bone regenerative potential of new osteoconductive implants. The novelty of the study lies in the analysis of the effectiveness of a novel two-step treatment which combines shot-blasting with a thermo-chemical treatment, at very short times after implant placement in a minipig model. MATERIALS AND METHODS: Three hundred twenty implants with four different surface treatments, namely bioactivated surfaces, micro-rough grit-blasted, micro-rough acid-etched and smooth as-machined titanium implants were placed into the bone of 20 minipigs. The percent of bone-to-implant contact was determined 3 days, 1, 2, 3 and 10 weeks after implant placement by histomorphometric analysis. Surface composition, topography and wettability of the implant specimens were analysed. RESULTS: The combination of shot-blasting and thermo-chemical treatment accelerated bone regeneration at early stages in comparison with all other treatments between day 3 and week 3 (p < 0.05). The value of osseointegration attained at week 2 was maintained until the end of the experiment without any significant changes (percent direct contact ≈ 85 %). This was mostly attributed to the ability of these implants to form in vivo a layer of apatitic mineral that coated the implant and could rapidly stimulate bone nucleation and growth from the implant surface. CONCLUSIONS: The surface quality resulting from this treatment on cpTi provided dental implants with a unique ability of rapid bone regeneration and osseointegration. CLINICAL RELEVANCE: This treatment represents a step forward in the direction of reducing the time prior to implant loading.
    Clinical Oral Investigations 03/2013; · 2.20 Impact Factor
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    ABSTRACT: β-type titanium alloys with low Young's modulus are desirable to reduce stress shielding effect and enhance bone remodeling for implants used to substitute failed hard tissue. For biomaterials application, the surface bioactivity is necessary to achieve optimal osseointegration. In the previous work, the low elastic modulus (43 GPa) Ti-25Nb-16Hf (wt %) alloy was mechanically and microstructurally characterized. In the present work, the biological behavior of Ti-25Nb-16Hf was studied. The biological response was improved by surface modification. The metal surface was modified by oxygen plasma and subsequently silanized with 3-chloropropyl(triethoxy)silane for covalent immobilization of the elastin-like polymer. The elastin-like polymer employed exhibits RGD bioactive motives inspired to the extracellular matrix in order to improve cell adhesion and spreading. Upon modification, the achieved surface presented different physical and chemical properties, such as surface energy and chemical composition. Subsequently, osteoblast adhesion, cell numbers, and differentiation studies were performed to correlate surface properties and cell response. The general tendency was that the higher surface energy the higher cell adhesion. Furthermore, cell culture and immunofluorescence microscopy images demonstrated that RGD-modified surfaces improved adhesion and spreading of the osteoblast cell type. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
    Journal of Biomedical Materials Research Part A 09/2012; · 2.83 Impact Factor
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    ABSTRACT: Aim: The effective results shown in the porous systems of tantalum employed for the use of osseointegrates has been demonstrated by means of animal experimentation. However, there is a total lack of any research studies on the osseointegration of tantalum implants from retrieval of the same after a period of time whereby the material had been implanted within the human body. Materials and Methods: For this study, five rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty months. Results: Observation during this study has confirmed the effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. The bone ingrowth, however, proved to be slower and less intense than that resulting within animal species during the first few months after implantation. Conclusions: Nevertheless, the results obtained in the quantitative assessment of this process proved to be similar to those results achieved by other authors in previous experimental work studies.
    Journal of applied biomaterials & functional materials. 03/2012; 10(1):e29-36.
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    ABSTRACT: This study sought to determine whether the mechanical properties of titanium dental implants changed after exposure to bacteria. Two strains of bacteria (Streptococcus sanguinis and Lactobacillus salivarius) were used in the study. The adhesive properties of the two strains were investigated as follows. Titanium implants were placed in bacteria broth, seeded with the two bacteria strains, and left in the broth for 1 or 3 months. Another group of titanium implants was immersed in artificial saliva at 37°C for 3 months. Ten implants in each group were tested in 37°C artificial saliva to evaluate their mechanical flexural strength and fatigue life. The bacterial cultures grew quickly on titanium surfaces. After 1 month of bacteria culture in vitro, the bacteria had produced corrosion pits on the titanium surfaces. After 3 months of bacterial culture, a 7% decrease in the flexural strength of the implant samples and a decrease of 15% in the number of cycles to failure by fatigue were seen versus implants not exposed to bacteria. These results demonstrate that, in physiologic conditions in vitro, bacteria have the capacity to produce a pitting corrosion phenomenon on exposed titanium surfaces, leading to a significant deterioration in the mechanical properties of the implant. It is therefore logical to conclude that bacteria may produce corrosion that reduces the useful life of dental implants.
    The International journal of oral & maxillofacial implants 01/2012; 27(1):64-8. · 1.91 Impact Factor
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    ABSTRACT: In oral orthodontic treatments, achievement of a good adhesion between brackets and teeth surfaces is essential. One way to increase adhesion is to apply a surface treatment of teeth facing surfaces through the projection of abrasive particles to produce a surface roughness which improves adhesion of the bracket to the tooth, because of the significantly increased contact between the two surfaces. The effect on adhesion through the use of this technique in different types of brackets, as well as through the use of different blasting particles, however, is yet not well described. In this study we have included three types of brackets which are commonly used in orthodontic therapies (two of them a mesh-type and the third one a micro-milled type) with a contact surface area of 11.16, 8.85 and 6.89 mm(2) respectively. These brackets were used combined with a sandblasting treatment with two different types of abrasive particles, alumina (Al(2)O(3)) and silicon carbide (SiC) and applied to natural teeth in vitro. The abrasive particles used are bio-compatible and usually used in achieving increased roughness for improved adherence in biomedical materials. Sandblasting was performed at 2 bars for 2 s; three particle sizes were used: 80, 200 and 600 μm. Non-blasted samples were used as control. Each of the pieces were cemented to natural teeth with a self-curing composite. Samples were stored in physiologic serum at 5°C temperature. Tensile tests were performed with a universal testing machine. Brackets treated with sandblasted particles were measured to have an increased adhesion as compared to the control sample. The highest bond strength was measured for samples sandblasted with alumina particles of 80 and 200 μm combined with micro-milled brackets. The recorded stresses did not exceed the tensile strength of tooth enamel.
    Journal of Materials Science Materials in Medicine 12/2011; 23(2):605-11. · 2.14 Impact Factor
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    ABSTRACT: This work examines NiTi foams that have been treated using a new oxidation treatment for obtaining Ni-free surfaces that could allow the ingrowth of living tissue, thereby increasing the mechanical anchorage of implants. A significant increase in the real surface area of these materials can decrease corrosion resistance and favour the release of Ni. This chemical degradation can induce allergic reactions or toxicity in the surrounding tissues. This study determines the porosity, surface characteristics, phase transformation, mechanical properties, corrosion behaviour and Ni release into the simulated body fluid medium of foams treated by a new surface oxidation treatment that produces Ni-free surfaces. These foams have pores in an appropriate range of sizes and interconnectivity, and thus their morphology is similar to that of bone. Their mechanical properties are biomechanically compatible with bone. The titanium oxide on the surface significantly improves corrosion resistance and decreases nickel ion release, while barely affecting transformation temperatures.
    Journal of Materials Science Materials in Medicine 12/2007; 18(11):2123-9. · 2.14 Impact Factor
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    ABSTRACT: Yttria-stabilized tetragonal zirconia may undergo extensive transformation to the monoclinic phase under mechanical and/or hydrothermal stress, with degradation of mechanical and tribologic properties. We hypothesized progressive phase transformation of zirconia in service in vivo is directly related to the time of implantation and to patient-related factors. The subsequent decrease in fracture toughness and increase in surface roughness and wear are related to the increased monoclinic content. We performed a study on 47 yttria-stabilized tetragonal zirconia femoral heads retrieved from failed total hip arthroplasties after 2 to 10 years implantation. Age, weight, and activity of the patients were retrieved from clinical records. Monoclinic content, fracture toughness, surface roughness, and wear were measured. Strong correlations were found between monoclinic content in the weightbearing surface and time of implantation (r = 0.97) and between increase in monoclinic content and decrease in fracture toughness (r = -0.92), increase in surface roughness (r = 0.88), and increase in surface wear (r = 0.89). No correlation was observed between the increase in monoclinic content and the age, weight, or activity of the patients. Aging of zirconia in vivo is then a function of time in service, and the loss of surface properties is caused by the corresponding increase in monoclinic content.
    Clinical Orthopaedics and Related Research 10/2007; 462:122-9. · 2.79 Impact Factor
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    ABSTRACT: The effect of shot blasting treatment on the cyclic deformation and fracture behavior of a commercial pure titanium with two different microstructures; equiaxed (alpha-phase) and acicular (martensitic alpha'-phase) was investigated. Fatigue tests were carried out in artificial saliva at 37 degrees C. Cyclic deformation tests were carried out up to fracture and fatigue crack nucleation and propagation were analysed. Residual stresses were determined by means of X-ray diffraction. The results show that shot blasting treatment improves fatigue life in the different microstructures studied. The equiaxed phase has improved mechanical properties compared to the acicular one. Despite the fact that control of the variables of shot blasting is not precise because of the nature of the treatment, it improves the fatigue life by the fact that the initiation site of the fatigue crack changes from the surface of the specimen to the interior of the shot blasted specimen. This is a consequence of the layer of compressive residual stresses that the treatment generates on titanium surfaces. The acicular morphology of the martensite favors crack propagation along the interface of the alpha' plates. Shot blasting, which is widely used on titanium dental implants in order to favour their osseointegration, can also improve their fatigue resistance.
    Dental Materials 05/2007; 23(4):486-91. · 3.77 Impact Factor
  • The Medical journal of Malaysia 06/2004; 59 Suppl B:65-6.
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    ABSTRACT: It is well known that the osseointegration of the commercially pure titanium (c.p. Ti) dental implant is improved when the metal is shot blasted in order to increase its surface roughness. This roughness is colonised by bone, which improves implant fixation. However, shot blasting also changes the chemical composition of the implant surface because some shot particles remain adhered on the metal. The c.p. Ti surfaces shot blasted with different materials and sizes of shot particles were tested in order to determine their topographical features (surface roughness, real surface area and the percentage of surface covered by the adhered shot particles) and electrochemical behaviour (open circuit potential, electrochemical impedance spectroscopy and cyclic polarisation). The results demonstrate that the increased surface area of the material because of the increasing surface roughness is not the only cause for differences found in the electrochemical behaviour and corrosion resistance of the blasted c.p. Ti. Among other possible causes, those differences may be attributed to the compressive residual surface stresses induced by shot blasting. All the materials tested have an adequate corrosion and electrochemical behaviour in terms of its possible use as dental implant material.
    Biomaterials 02/2003; 24(2):263-73. · 8.31 Impact Factor
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    ABSTRACT: Wear tests were carried out to study the effect of the hardness and roughness with various counterface materials on UHMWPE wear behaviour. The materi-als used as counterfaces were based on varieties of CoCrMo: 1) forged (hand-polished) CoCrMo, 2) forged (mass-finished) CoCrMo, and 3) cast (mass-finished) CoCrMo. Additionally, two coatings were proposed: 1) a CoCrMo coating applied to the forged CoCrMo alloy by means of physical vapour deposi-tion (PVD), and 2) a ZrO 2 coating applied to the forged CoCrMo alloy by means of plasma-assisted chemical vapour deposition (PACVD). The recipro-cating pin-on-flat (RPOF) device for pin-on-disk wear testing was used for this study. The worn sur-faces were observed using optical, atomic force and scanning electron microscopes.
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    ABSTRACT: Wear tests were carried out to study the effect of various counterface materials in the wear behaviour of Ultra High Molecular Weight Polyethylene (UHMWPE). The materials used as counterfaces were based on varieties of CoCrMo: 1) forged (hand-pol-ished) CoCrMo; 2) forged (mass-finished) Co-CrMo; 3) cast (mass-finished) CoCrMo. Additionally, two coatings were proposed: 1) a CoCrMo coating applied to the forged CoCrMo alloy by means of physical vapour deposition (PVD); 2) a ZrO 2 coating applied to the forged CoCrMo alloy by means of plasma-assisted chemical vapour deposition (PACVD). The reciprocating pin-on-flat (RPOF) device for pin-on-disk wear testing was used for this study. The worn surfaces were observed using optical, atomic force and scanning electron microscopes.

Publication Stats

119 Citations
55.40 Total Impact Points

Institutions

  • 2014
    • University of Murcia
      Murcia, Murcia, Spain
  • 2007–2014
    • Polytechnic University of Catalonia
      • Research Center of Biomedical Engineering (CREB)
      Barcino, Catalonia, Spain
    • Universidad Politécnica de Cartagena
      Carthago Nova, Murcia, Spain
  • 2011
    • Universidad de Sevilla
      • Facultad De Odontología
      Sevilla, Andalusia, Spain