W implantologii kręgosłupowej stosowane są dwa typy implantów: „non-fusion” oraz „fusion”, czyli odpowiednio bez zrostu i ze zrostem kostnym. Większą grupę stanowią stabilizacje ze zrostem kostnym, dla których szybkość oraz jakość osteointegracji ma kluczowe znaczenie dla końcowego efektu leczenia. Najczęściej stosowanymi biomateriałami są stopy tytanu oraz polimer PEEK (polieteroeteroketon) o różnej topografii powierzchni 2D oraz przestrzennej konstrukcji 3D wynikających z zastosowanej obróbki wykańczającej, warstw powierzchniowych, metod wytwarzania. Wykazano, że osteointegracja zależy w dużym stopniu od m.in. odpowiedniej konfiguracji 2D i 3D, topografii, porowatości oraz energii powierzchniowej. W pracy przeanalizowano wpływ rodzaju biomateriału: stop Ti6Al4V ELI, PEEK Optima oraz technologii wytwarzania implantów: ubytkowa (PEEK, Ti), przyrostowa EBT - Electron Beam Technology (Ti-3D-Truss) na osteointegrację. Z zachowaniem analogicznych warunków procesu, jak przy produkcji implantów, przygotowano modele/próbki, które poddano badaniom biologicznym in vitro oraz in vivo na zwierzętach. Pobrane preparaty zwierzęce z modelami implantów oceniano pod kątem osteointegracji z użyciem przemysłowej tomografii rentgenowskiej CTt. Wyniki potwierdziły biokompatybilność badanych biomateriałów, a tym samym bezpieczeństwo stosowania w chirurgii kostnej. Implantowe stopy Ti6Al4V ELI w porównaniu z polimerem PEEK są korzystniejszymi biomateriałami na stabilizację międzytrzonową typu „fusion”. Polimer PEEK Optima jest dobrym materiałem w stabilizacjach typu „non-fusion”. Wykorzystanie technologii przyrostowej EBT do wytwarzania implantów z proszków Ti6Al4V ELI pozwala na uzyskanie „wulkanicznych” powierzchni oraz przestrzennych/ kratownicowych konstrukcji Ti-3D-Truss o dużym rozwinięciu powierzchniowym, które sprzyjają i przyspieszają przerost/obrost tkanki kostnej przez implant. Dotychczasowe doniesienia kliniczne wskazują na poprawę efektywności chirurgicznego leczenia, polegającego na przyspieszonym zroście kostnym w „mostowaniu” kręgosłupa z wykorzystaniem implantów międzytrzonowych typu Ti-3D-Truss.
EN
In spinal implantology there are two types of implants: “non-fusion” and “fusion”, that is without and with bone overgrowth, respectively. A larger group consists of stabilization with bone overgrowth, for which speed and quality of osseointegration is crucial for final treatment outcome. The most commonly used biomaterials are titanium alloys and polietero-eteroketon (PEEK) of different 2D surface topography and 3D spatial structure resulting from the finishing, surface layers or production methods. It has been shown that osseointegration depends largely on suitable configuration of 2D and 3D, topography, porosity and surface energy. The impact of biomaterial type: Ti6Al4V titanium alloy ELI, PEEK OPTIMA and implant production technology: deficient (PEEK, Ti), incremental EBT-Electron Beam Technology (Ti-3D-Truss) on the osseointegration were analyzed. In compliance with corresponding process conditions of implant production, models/samples were prepared and subjected to in vitro biological tests and in vivo animal tests. Collected animal specimens with implants models were tested for osseointegration with the use of CTt tomography. The results confirmed the biocompatibility of tested biomaterials, and thus safety in the bone surgery. Ti6Al4V ELI alloys compared with PEEK polymer are favourable biomaterials for “fusion” interbody stabilization. The polymer PEEK Optima is preferred material for “non-fusion” stabilizations. The use of EBT technology for implant production made of Ti6Al4V ELI powder allows to obtain “volcanic” surfaces and spatial/lattice Ti-3D-Truss structures with a large surface area which accelerate the bone over-/in-growth through the implant. Previous reports indicate improved clinical effectiveness of surgical treatment involving the accelerated bone overgrowth in the “bridging” of spine with the use of Ti-3D-Truss interbody implants.
Purpose: Characterization of the electrochemical behavior of anodized implant rods made of the titanium alloy Ti6Al4V ELI after immersion in air-saturated Ringer's solution was presented in the paper. Design/methodology/approach: The anodized and deformed by bending at angle 20° specimens (dia 6 mm) were characterized electrochemically in two zones: the max tensile (I) and the max. compressive stress (II). Impedance spectra (EIS) and corrosion potential measurements were performed on 1, 6, 10 and 16th day after immersion in Ringer's solution. Findings: Bending caused an apparent decrease of the protective properties of the anodic layer, but the characteristic two-layer anodic film and the values of corrosion potentials were restored due to immersion in Ringer's solution. The regions of the compressive stresses show much stronger tendency to regenerate surface properties. Research limitations/implications: The electrochemical tests in Ringer's solution performed only in static conditions will be followed by fatigue tests in SBF. Practical implications: Results of the work are of great importance for surgical practice in the pre-operative stage of spinal surgery procedures. The explanation of the observed phenomena is proposed. Originality/value: Different stress zones formed on implant alloy during bending were described electrochemically. Results of studies evidenced that changes in the electrochemical behaviour in vitro in Ringer's solution are advantageous with regard to the protective properties of the investigated alloy.
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W pracy charakteryzowano elektrochemiczne własności warstw tlenkowych na implantowym stopie tytanu Ti6A14V ELI powstałych w procesach: polerowania oraz anodowania. Oceniano także wpływ odkształceń plastycznych wywołanych gięciem na zachowanie in vitro obu warstw. Badania prowadzono po 1 i 37 dniach przechowywania w roztworze Ringera. Do oceny zachowania warstw tlenkowych zastosowano pomiary potencjałów korozyjnych, interpretację krzywych polaryzacyjnych oraz elektrochemiczną spektroskopię impedancyjną. Rezultaty badań wykazały różnice w zachowaniach naturalnej oraz anodowej warstwy-tlenkowej przy dążeniu do stanu "równowagi", odpowiadającego warunkom badań in vitro.
EN
In this investigation, the behavior of oxide layers titanium alloy Ti6A14V arised during: anodizing and polishing was characterized in bending test. Influence of plastic deformations on both layers was estimated in vitro. Measurements were performed after 1 and 37 days immersion in Ringer's solution. The behavior of layers was characterized by electrochemical testing (anodizing polarization, EIS and corrosion potential). A measurement of corrosion potential, electrochemical impedance, spectroscopy and interpretation of polarization curves was used to estimate oxide layers. Results of investigation show differences between natural and anodic oxide layers. Bending gives positive influence on bioactivity.
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A comprehensive comparative study of binary oxide systems obtained by the sol-gel chemistry has been made. Particular attention has been paid to the texture changes. Using germanium isopropoxide and aluminium isopropoxide, binary gels with mesoporous structure have been obtained. Binary gels show a monodispersive distribution and the major contribution to the pore volume comes from the pores of diameters similar to those in the pure alumina gel.
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Purpose: Evaluation of the influence of plastic deformation and characterization of the electrochemical behaviour of anodized implant rods made of the titanium alloy Ti6Al4V after immersion in air-saturated Ringer’s solution was presented in the paper. Design/methodology/approach: The specimens (dia 6 mm) were anodized and deformed by bending at angle 20o. The comparative characteristics of two zones: the max tensile (I) and the max. compressive stress (II) was based on the determination of electrochemical properties. Impedance spectra (EIS) and corrosion potential measurements were performed on 1, 6, 10 and 16th day after immersion in Ringer`s solution. Findings: Although bending caused an apparent decrease of the protective properties of the anodic layer, the characteristic two-layer anodic film and the values of corrosion potentials were restored due to immersion in Ringer’s solution. The regions of the compressive stresses show the much stronger tendency to restore. Research limitations/implications: The electrochemical tests in Ringer’s solution were performed only in static conditions. Fatigue tests in SBF are in progress. Practical implications: The explanation of the observed phenomena is proposed. Results of the work are of great importance for surgical practice in the pre-operative stage of spinal surgery procedures. Originality/value: Various stress zones formed on implant alloy during bending were described. The results of studies presented in the paper evidenced that changes noticed in the electrochemical behaviour in vitro in Ringer’s solution are advantageous with regard to the protective properties of the investigated alloy.
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Purpose: The plastic deformation behaviour of the anodized binary titanium alloy Ti6Al4V was characterized in mechanical and electrochemical tests. Design/methodology/approach: The effect of tensile and compressive stresses on properties of different clinically relevant surfaces of the deformed by bending implant rods was investigated. The deformation behaviour was characterized by FEM analysis. Relevant surfaces in tensile and compressive zones were characteristics by microhardness and roughness measurements, and electrochemical testing (Ecor, anodic polarization, EIS) in oxygen-saturated Ringer’s solution. Findings: It was concluded that bending influenced mostly the properties of material in the tensile zone of the specimen, whereas the properties of surface layer in the compressive zone and the properties of surface layer in tensile zone after rebending are comparable and not so severe. Research limitations/implications: Studies were performed in static conditions, fatique studies are planned in the future. Practical implications: Results are of great importance in for surgical practice in the in the evaluation of the influence of shaping process applied during pre-operative procedures on the performance of spinal implant systems. Originality/value: In the paper a typical pre-operative procedure of shaping was applied to anodized titanium implants in order to evaluate its influence on the characteristics of the surface layer. Studies were focused on the safety their application in vivo.