The aim of this study was to determine the influence of long-term exposure of Ringer’s solution on degradation of the anodically oxidated Ti6Al4V alloy coated with a biodegradable polymer coating. Polymeric coatings made of poly(glycolide-ε-caprolactone) – G-Cap and poly(glycolide- ε-caprolactone-lactide) – G-Cap-L were applied by a dip-coating method. Degradation was assessed on the basis of the results of pitting corrosion resistance and density of metal ions infiltrating to the solution. Studies were conducted for samples after 3, 6, 8, 10 and 12 weeks of exposure to the corrosive environment. In addition, topography of the surface of the polymer coating was assessed. As a result of potentiodynamic studies, the value of the polarization resistance and corrosion potential for the G-Cap and G-Cap-L coated samples were significantly decreased while simultaneous reduction of the density of metal ions infiltrating to the solution throughout the whole study period. There was also observed a faster degradation of the G-Cap coating compared to G-Cap-L, which showed local discontinuity after 12 weeks of exposure. The obtained results provide the basis for the development of polymeric coatings on surface of metal implants with predictable time / kinetics of degradation by selecting the composition of polymers while simultaneous limitation of metal ions infiltration into surrounding tissues.

Currently, various modifications to surfaces are made more and more frequently in order to improve implants' haemocompatibility. The main criterion determining the applicability of the respective surface-modification method is obtaining a product featuring suitable functional properties. These properties depend to a great extent on the corrosion resistance in the environment of human blood. Subject-matter literature does not devote much attention to the sterilisation process for titanium and cpTi alloys with surface modifications. A problem that still remains unsolved is the selection of a proper test showing the full characteristics of their behaviour contact with a blood environment during the time that the implant is used. Therefore, the authors of this study made an attempt to evaluate the impact of medical sterilisation methods, i.e., the ethylene oxide anodic oxide and SiO2 layer, by means of the sol-gel method. The efficiency of the suggested technology for oxide layer application was evaluated on the basis of mechanical and electrochemical tests. Sterilisation in ethylene oxide and steam had a favourable influence on the electrochemical and mechanical properties of cpTi, irrespective of the method of surface preparation. In order to simulate real conditions, the tests were performed in artificial plasma at a temperature of T = 37 ± 1°C and pH = 7.0 ± 0.2. The results proved the diversification of electrochemical properties of the oxide layers, depending on the technological parameters of its application. The suggestion of proper variants of the surface modification with the application of electrochemical and chemical methods is of long-range importance and will contribute to the development of technological conditions with specific parameters for the creation of oxide layers on metallic implants made of cpTi. Keywords: cpTi (Grade 4), SiO 2 , TiO 2 , mechanical properties, electrochemical properties Vedno pogosteje se opravljajo razli~ne modifikacije povr{ine, da bi se izbolj{ala hemokompatibilnost vsadkov. Glavni kriterij, ki dolo~a uporabnost metode za modifikacijo povr{ine je, da proizvod poka`e primerne funkcionalne lastnosti. Te lastnosti so v veliki meri odvisne od korozijske odpornosti v~love{ki krvi. Obstoje~a literatura ne posve~a velike pozornosti postopku sterilizacije titana in cpTi zlitin z modificirano povr{ino. Problem, ki {e ni re{en, je izbira primernega preizkusa, ki bi pokazal vse zna~ilnosti o obna{anju stika s krvjo med uporabo vsadka. Zato so avtorji v tej {tudiji poizkusili oceniti vpliv medicinskih metod sterilizacije, kot je etilen oksid anodni oksid in SiO2 plast izdelano s pomo~jo metode sol-gel. Predlagana tehnologija uporabe oksidnega sloja je bila ocenjena z mehanskimi in elektrokemijskimi preizkusi. Sterilizacija v etilen oksidu in pari je imela ugodne vplive na elektrokemijske in mehanske lastnosti cpTi, ne glede na na~in priprave povr{ine. Za simulacijo realnih pogojev so bili preizkusi izvr{eni v umetni plazmi pri temperaturi T = 37 ± 1°C in pH = 7,0 ± 0,2. Dobljeni rezu...

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The aim of the study was to determine the influence of long term exposure to Ringer's solution of biodegradable polymer coatings containing an active substance on the Ti6Al7Nb alloy substrate on the physical and chemical properties of the coatings and the degradation process of the metal substrate. The studies used poly(L-lactide-co-trimethylene carbonate) P(L/TMC), poly(L-lactide-co-trimethylene carbonate-glycolide) P(L/TMC/G) and poly(D,L-lactide-glycolide) (PLGA) coatings applied to the anodically oxidized Ti6Al7Nb alloy by means of dipping method (1, 2 and 3 dips). The polymer coatings contained ciprofloxacin. Roughness and wettability tests were carried out on the substrate and polymer coatings, the pitting corrosion resistance of the substrate and samples with polymer coating was determined, the number of metallic ions released to the solution from the coated and uncoated samples was determined as well as the adhesion of polymer coatings. The research was supplemented by microscopic observations. The results of the research indicate different influence of exposure to Ringer's solution on the physical and chemical properties of biodegradable polymer coatings containing ciprofloxacin and the course of the degradation process of the metal substrate.

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EvaluatIoN of corrosIoN rEsIstaNcE of tItaNIuM alloys usEd for MEdIcal IMplaNtsThe study presents the results of investigations of modeling the usable properties of implant surfaces made of Ti6Al7Nb alloy, using the example of a dynamic hip screw (DHS) applied in surgical treatment of intertrochanteric femoral neck fractures. Numerical simulation has been performed for the model load of femoral fixation with DHS screw. The load simulation results provided the basis to select mechanical properties of the fixator elements and to define those fixation areas which are mostly susceptible to development of corrosion. The surfaces of Ti6Al7Nb alloy were ground, vibro-abrasive machined, mechanically polished, sandblasted, anode oxidized at different voltage values and steam sterilized. Results of surface topography evaluation, resistance to pitting and crevice corrosion as well as degradation kinetics of the outer layer were presented. Usability of the formed passive layer in clinical applications was evaluated through wear and corrosion tests of the femoral fixation model. The test results proved usefulness of the proposed surface modification methods for clinical application of different size and shape implants

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The paper presents the influence of mechanical surface damage on the physicochemical properties of plates after implantation made of crnimo stainless steel, used in the treatment of anterior surface deformity of the chest. analysis of the data allowed us to investigate the effect of implant design and condition of their surface on the results of chest deformation treatment. results of electrochemical, impedance and surface wettability tests and Sem observations were compared with clinical observations. When removing the plates we found only slight inflammatory-periosteal reactions. On the basis of obtained results, it can be stated that plates, in spite of mechanical damage of the surface, were characterized by good corrosion resistance, a fact which is confirmed by the results of clinical evaluation.