Ivana Dimic | University of Belgrade (original) (raw)
Papers by Ivana Dimic
Journal of Biomedical Materials Research Part B: Applied Biomaterials
The purpose of this study was to estimate the electrochemical behavior and biocompatibility of ul... more The purpose of this study was to estimate the electrochemical behavior and biocompatibility of ultrafine-grained (UFG) commercially pure titanium (CPTi) and Ti-13Nb-13Zr (TNZ) alloy obtained by high-pressure torsion process. Electrochemical behavior of materials in artificial saliva at 37°C was evaluated by potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS), and the obtained results indicated that UFG TNZ alloy showed corrosion current density (j = 53 ± 5 nA cm ) which was 2 times lower compared to coarse-grained (CG) TNZ alloy (j = 110 ± 12 nA cm ) and higher corrosion resistance, while UFG CPTi and CPTi showed approximately the same corrosion rate (mean j ∼ 38-40 nA cm ). Static immersion test in artificial saliva, performed in this study, showed that the released ion concentrations from UFG materials were more than 10 times lower than the permitted concentration (the highest released Ti ion concentration from UFG CPTi and UFG TNZ alloy was 1.12 and 1.28 ppb, respectively, while permitted concentration was 15.5 ppb). The in vitro cytotoxicity tests, as the initial phase of the biocompatibility evaluation, showed that the fraction of surviving cells in all examined materials was much higher compared to the control sample and hence demonstrated absence of cytotoxicity and an increase of fibroblast cells adhesion on UFG materials surfaces. UFG CPTi and UFG TNZ alloy can be considered as promising materials for applications in dentistry due to high corrosion resistance and outstanding biocompatibility which were shown in this study. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1097-1107, 2018.
Journal of the Serbian Chemical Society, 2015
Metallic materials, such as Co-Cr-Mo alloys, are exposed to aggressive conditions in the oral cav... more Metallic materials, such as Co-Cr-Mo alloys, are exposed to aggressive conditions in the oral cavity that represents an ideal environment for metallic ion release and biodegradation. The metallic ions released from dental materials can cause local and/or systemic adverse effects in the human body. Therefore, dental materials are required to possess appropriate mechanical, physical, chemical and biological properties. The biocompatibility of metallic materials is very important for dental applications. Accordingly, the aim of this study was to examine metallic ion release and cytotoxicity of Co-30Cr-5Mo cast alloy as the initial phase of biocompatibility evaluation. Determination of the viability of human (MRC-5) and animal (L929) fibroblast cells were conducted using three in vitro test methods: the colorimetric methyl-thiazoltetrazolium (MTT) test, the dye exclusion test (DET) and the agar diffusion test (ADT). Furthermore, the morphology and growth of the cells were analyzed using scanning electron microscopy (SEM). The obtained results indicated that Co-30Cr-5Mo alloy did not release harmful elements in concentrations high enough to have detrimental effects on human and animal fibroblasts under the given experimental conditions. Moreover, the fibroblast cells showed good adhesion on the surface of the Co-30Cr-5Mo alloy. Therefore, it could be concluded that Co-30Cr-5Mo alloy is a biocompatible material that could be safely used in dentistry.
Procedia Materials Science, 2014
Working conditions of casing pipes in drilling rigs can significantly influence the initiation an... more Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a steel pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are often exposed to damages at the external surface. Analyzed crack is in axial direction, bearing in mind that this type of defect most significantly decreases the load carrying capacity of the cylindrical pressurized components. A pipe segment exposed to internal pressure is analyzed experimentally and numerically, using the finite element method. The experimental setup included the tracking of crack mouth opening displacement (CMOD) values, as well as J integral, which is determined by application of direct measurement. Criteria for pipe failure are determined on finite element models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. The size of the crack is varied in the finite element models; several 3D models with different crack sizes (length and depth) are evaluated. Dependence of maximum internal pressure on the defect size is obtained. 2D plane strain models are also examined, with an aim to determine the applicability limits of this simplified approach. Based on the obtained results, integrity assessment criteria for the analyzed geometries are discussed.
The metal ion release from the implant material occurs as a direct consequence of the corrosion p... more The metal ion release from the implant material occurs as a direct consequence of the corrosion process. Corrosion rate depends on the material microstructure and surface roughness, as well as on composition, temperature and pH of the chemical environment. The aim of this study was to determine the type and the amount of released metal ions from Co-based alloy (Wironit® extrahard, Bego, Germany) and commercially pure (CP) Ti (grade 2). Disk-shaped samples of commercial Co-based alloy and CP Ti (8.0 mm in diameter and 3.2 mm in thickness) were immersed in artificial saliva with different pH (4.0; 5.5 and 7.5) and incubated at 37 ºC using a thermostat. The type and amount of ions released from the metallic implant materials were determined after 1, 3 and 6 weeks of immersion using Inductively Coupled Plasma - Mass Spectrometer (Agilent ICP-MS 7500ce). The results of the study show that the amount of released metal ions is increased with the decrease of the artificial saliva pH value. ...
Tehnicki Vjesnik
Original scientific paper Since local defects reduce the load-carrying capacity and deformation a... more Original scientific paper Since local defects reduce the load-carrying capacity and deformation ability of a piping system, an analysis is undertaken to quantify the influence of weld defects on integrity of the pipe elbows subjected to internal pressure. Incompletely filled groove is examined, because this type of defect was previously detected by ultrasonic measurement on the inner surface of the pipeline from a hydro-power plant. Three-dimensional finite element analysis is conducted using Abaqus software package. The influence of weld defect geometry (its depth, length and location) on the elbow integrity is determined. Additionally, decrease of load carrying capacity is determined for the case when a crack has initiated at the bottom of the defect. The influence of finite element type (hexahedral or tetrahedral) is examined. Utjecaj grešaka u zavarenom spoju na integritet cijevnih lukova izloženih djelovanju unutarnjeg tlaka Izvorni znanstvenu članak Imajući u vidu da lokalna o...
Acta periodica technologica, 2012
The significance of composite materials and their applications are mainly due to their good prope... more The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite materials. This study represents a contribution to the field of mechanical properties of the recycled composite materials. The tension mechanical properties (tensile strength and modulus of elasticity) of once used and disposed glass-epoxy composite material were compared before and after the recycling. The obtained results from mechanical tests confirmed that the applied recycling method was suitable for glass-epoxy composite materials. In respect to the tensile strength and modulus of elasticity it ca...
Acta periodica technologica, 2013
Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Yo... more Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Young's modulus, high corrosion resistance, and outstanding biocompatibility, titanium and its alloys are the most used metallic materials for biomedical applications. In dental practice, these materials have demonstrated success as biomedical devices which are used for repairing and replacing failed hard tissue. However, the oral cavity is constantly subjected to the changes in the pH value changes and such an environment is strongly corrosive for titanium dental implants. The objective of this study was to examine ion release from commercially pure titanium (cpTi) in artificial saliva with different pH values (4.0, 5.5 and 7.5). The concentrations of released titanium ions were determined after 1, 3 and 6 weeks using Inductively Coupled Plasma-Mass Spectrometry. The results indicate that the ion release from commercially pure titanium in the artificial saliva is dependent both on the pH of artificial saliva and duration of immersion.
Acta periodica technologica, 2013
The main objective of the research presented in this paper was to carry out a statistical-mechani... more The main objective of the research presented in this paper was to carry out a statistical-mechanical analysis concerning the tensile test of glass-epoxy composite materials in order to calculate their relevant tension properties and micromechanical structure destruction process. The analysis was done at room temperature, and its results were derived based on the structure of the glass woven 280 g/m?, ?twill texture? with the width value of 100 cm, type - Interglass 92125, and epoxy resin type MGS L 135. Samples were shaped by hands with 35% of fabric volume part. The consumed portion of resin was 220 g/m?, the thickness of the laminate was 0.308 mm, and the mass of the laminate was 500 g/m2. There were a total of eight layers built in the panel. The micromechanical analysis was derived from the crack surfaces data collected on a scanning electronic microscope, and it showed the mechanisms of damage, and development of cracks until the occurrence of the final break under the tension ...
Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Yo... more Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Young's modulus, high corrosion resistance, and outstanding biocompatibility, titanium and its alloys are the most used metallic materials for biomedical applications. In dental practice, these materials have demonstrated success as biomedical devices which are used for repairing and replacing failed hard tissue. However, the oral cavity is constantly subjected to the changes in the pH value changes and such an environment is strongly corrosive for titanium dental implants. The objective of this study was to examine ion release from commercially pure titanium (cpTi) in artificial saliva with different pH values (4.0, 5.5 and 7.5). The concentrations of released titanium ions were determined after 1, 3 and 6 weeks using Inductively Coupled Plasma-Mass Spectrometry. The results indicate that the ion release from commercially pure titanium in the artificial saliva is dependent both on the pH of artificial saliva and duration of immersion.
Article Highlights • Metallic ion release from Co-Cr-Mo alloy in artificial saliva is examined • ... more Article Highlights • Metallic ion release from Co-Cr-Mo alloy in artificial saliva is examined • The concentrations of released ions are determined using ICP-MS • The effects of artificial saliva pH values and duration of immersion on metallic ion release are determined • The released metallic ions concentrations are compared with literature data Abstract Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release, which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5). After a certain immersion period (1, 3 and 6 weeks) the concentrations of released ions were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy.
Journal of Biomedical Materials Research Part B: Applied Biomaterials
The purpose of this study was to estimate the electrochemical behavior and biocompatibility of ul... more The purpose of this study was to estimate the electrochemical behavior and biocompatibility of ultrafine-grained (UFG) commercially pure titanium (CPTi) and Ti-13Nb-13Zr (TNZ) alloy obtained by high-pressure torsion process. Electrochemical behavior of materials in artificial saliva at 37°C was evaluated by potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS), and the obtained results indicated that UFG TNZ alloy showed corrosion current density (j = 53 ± 5 nA cm ) which was 2 times lower compared to coarse-grained (CG) TNZ alloy (j = 110 ± 12 nA cm ) and higher corrosion resistance, while UFG CPTi and CPTi showed approximately the same corrosion rate (mean j ∼ 38-40 nA cm ). Static immersion test in artificial saliva, performed in this study, showed that the released ion concentrations from UFG materials were more than 10 times lower than the permitted concentration (the highest released Ti ion concentration from UFG CPTi and UFG TNZ alloy was 1.12 and 1.28 ppb, respectively, while permitted concentration was 15.5 ppb). The in vitro cytotoxicity tests, as the initial phase of the biocompatibility evaluation, showed that the fraction of surviving cells in all examined materials was much higher compared to the control sample and hence demonstrated absence of cytotoxicity and an increase of fibroblast cells adhesion on UFG materials surfaces. UFG CPTi and UFG TNZ alloy can be considered as promising materials for applications in dentistry due to high corrosion resistance and outstanding biocompatibility which were shown in this study. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1097-1107, 2018.
Journal of the Serbian Chemical Society, 2015
Metallic materials, such as Co-Cr-Mo alloys, are exposed to aggressive conditions in the oral cav... more Metallic materials, such as Co-Cr-Mo alloys, are exposed to aggressive conditions in the oral cavity that represents an ideal environment for metallic ion release and biodegradation. The metallic ions released from dental materials can cause local and/or systemic adverse effects in the human body. Therefore, dental materials are required to possess appropriate mechanical, physical, chemical and biological properties. The biocompatibility of metallic materials is very important for dental applications. Accordingly, the aim of this study was to examine metallic ion release and cytotoxicity of Co-30Cr-5Mo cast alloy as the initial phase of biocompatibility evaluation. Determination of the viability of human (MRC-5) and animal (L929) fibroblast cells were conducted using three in vitro test methods: the colorimetric methyl-thiazoltetrazolium (MTT) test, the dye exclusion test (DET) and the agar diffusion test (ADT). Furthermore, the morphology and growth of the cells were analyzed using scanning electron microscopy (SEM). The obtained results indicated that Co-30Cr-5Mo alloy did not release harmful elements in concentrations high enough to have detrimental effects on human and animal fibroblasts under the given experimental conditions. Moreover, the fibroblast cells showed good adhesion on the surface of the Co-30Cr-5Mo alloy. Therefore, it could be concluded that Co-30Cr-5Mo alloy is a biocompatible material that could be safely used in dentistry.
Procedia Materials Science, 2014
Working conditions of casing pipes in drilling rigs can significantly influence the initiation an... more Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a steel pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are often exposed to damages at the external surface. Analyzed crack is in axial direction, bearing in mind that this type of defect most significantly decreases the load carrying capacity of the cylindrical pressurized components. A pipe segment exposed to internal pressure is analyzed experimentally and numerically, using the finite element method. The experimental setup included the tracking of crack mouth opening displacement (CMOD) values, as well as J integral, which is determined by application of direct measurement. Criteria for pipe failure are determined on finite element models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. The size of the crack is varied in the finite element models; several 3D models with different crack sizes (length and depth) are evaluated. Dependence of maximum internal pressure on the defect size is obtained. 2D plane strain models are also examined, with an aim to determine the applicability limits of this simplified approach. Based on the obtained results, integrity assessment criteria for the analyzed geometries are discussed.
The metal ion release from the implant material occurs as a direct consequence of the corrosion p... more The metal ion release from the implant material occurs as a direct consequence of the corrosion process. Corrosion rate depends on the material microstructure and surface roughness, as well as on composition, temperature and pH of the chemical environment. The aim of this study was to determine the type and the amount of released metal ions from Co-based alloy (Wironit® extrahard, Bego, Germany) and commercially pure (CP) Ti (grade 2). Disk-shaped samples of commercial Co-based alloy and CP Ti (8.0 mm in diameter and 3.2 mm in thickness) were immersed in artificial saliva with different pH (4.0; 5.5 and 7.5) and incubated at 37 ºC using a thermostat. The type and amount of ions released from the metallic implant materials were determined after 1, 3 and 6 weeks of immersion using Inductively Coupled Plasma - Mass Spectrometer (Agilent ICP-MS 7500ce). The results of the study show that the amount of released metal ions is increased with the decrease of the artificial saliva pH value. ...
Tehnicki Vjesnik
Original scientific paper Since local defects reduce the load-carrying capacity and deformation a... more Original scientific paper Since local defects reduce the load-carrying capacity and deformation ability of a piping system, an analysis is undertaken to quantify the influence of weld defects on integrity of the pipe elbows subjected to internal pressure. Incompletely filled groove is examined, because this type of defect was previously detected by ultrasonic measurement on the inner surface of the pipeline from a hydro-power plant. Three-dimensional finite element analysis is conducted using Abaqus software package. The influence of weld defect geometry (its depth, length and location) on the elbow integrity is determined. Additionally, decrease of load carrying capacity is determined for the case when a crack has initiated at the bottom of the defect. The influence of finite element type (hexahedral or tetrahedral) is examined. Utjecaj grešaka u zavarenom spoju na integritet cijevnih lukova izloženih djelovanju unutarnjeg tlaka Izvorni znanstvenu članak Imajući u vidu da lokalna o...
Acta periodica technologica, 2012
The significance of composite materials and their applications are mainly due to their good prope... more The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite materials. This study represents a contribution to the field of mechanical properties of the recycled composite materials. The tension mechanical properties (tensile strength and modulus of elasticity) of once used and disposed glass-epoxy composite material were compared before and after the recycling. The obtained results from mechanical tests confirmed that the applied recycling method was suitable for glass-epoxy composite materials. In respect to the tensile strength and modulus of elasticity it ca...
Acta periodica technologica, 2013
Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Yo... more Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Young's modulus, high corrosion resistance, and outstanding biocompatibility, titanium and its alloys are the most used metallic materials for biomedical applications. In dental practice, these materials have demonstrated success as biomedical devices which are used for repairing and replacing failed hard tissue. However, the oral cavity is constantly subjected to the changes in the pH value changes and such an environment is strongly corrosive for titanium dental implants. The objective of this study was to examine ion release from commercially pure titanium (cpTi) in artificial saliva with different pH values (4.0, 5.5 and 7.5). The concentrations of released titanium ions were determined after 1, 3 and 6 weeks using Inductively Coupled Plasma-Mass Spectrometry. The results indicate that the ion release from commercially pure titanium in the artificial saliva is dependent both on the pH of artificial saliva and duration of immersion.
Acta periodica technologica, 2013
The main objective of the research presented in this paper was to carry out a statistical-mechani... more The main objective of the research presented in this paper was to carry out a statistical-mechanical analysis concerning the tensile test of glass-epoxy composite materials in order to calculate their relevant tension properties and micromechanical structure destruction process. The analysis was done at room temperature, and its results were derived based on the structure of the glass woven 280 g/m?, ?twill texture? with the width value of 100 cm, type - Interglass 92125, and epoxy resin type MGS L 135. Samples were shaped by hands with 35% of fabric volume part. The consumed portion of resin was 220 g/m?, the thickness of the laminate was 0.308 mm, and the mass of the laminate was 500 g/m2. There were a total of eight layers built in the panel. The micromechanical analysis was derived from the crack surfaces data collected on a scanning electronic microscope, and it showed the mechanisms of damage, and development of cracks until the occurrence of the final break under the tension ...
Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Yo... more Due to their excellent characteristics, such as chemical inertness, mechanical resistance, low Young's modulus, high corrosion resistance, and outstanding biocompatibility, titanium and its alloys are the most used metallic materials for biomedical applications. In dental practice, these materials have demonstrated success as biomedical devices which are used for repairing and replacing failed hard tissue. However, the oral cavity is constantly subjected to the changes in the pH value changes and such an environment is strongly corrosive for titanium dental implants. The objective of this study was to examine ion release from commercially pure titanium (cpTi) in artificial saliva with different pH values (4.0, 5.5 and 7.5). The concentrations of released titanium ions were determined after 1, 3 and 6 weeks using Inductively Coupled Plasma-Mass Spectrometry. The results indicate that the ion release from commercially pure titanium in the artificial saliva is dependent both on the pH of artificial saliva and duration of immersion.
Article Highlights • Metallic ion release from Co-Cr-Mo alloy in artificial saliva is examined • ... more Article Highlights • Metallic ion release from Co-Cr-Mo alloy in artificial saliva is examined • The concentrations of released ions are determined using ICP-MS • The effects of artificial saliva pH values and duration of immersion on metallic ion release are determined • The released metallic ions concentrations are compared with literature data Abstract Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release, which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5). After a certain immersion period (1, 3 and 6 weeks) the concentrations of released ions were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy.