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Influence the heat treatment of two base metal alloys used on dental prosthesis on corrosion resistance

Reimann Ł., Dobrzański L.A., Nieradka B., Kusy M., Riedlmajer R.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 57, nr 2

83--90

EN

Purpose: The goal of the study is to try find the influence of the heat treatment on the corrosion resistance of two base cobalt alloys used on dental prosthesis. Design/methodology/approach: The investigation was choosen two base cobalt alloys: Remanium 2000+ (Dentaurum) and Wirobond LFC (Bego). Corrosion resistance test were carried out at room temperature and use of the Potentiostat IPS AJ PGU system for electrochemical tests. The examination use of water center which simulated artificial saliva environment. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with use the potentiodynamic methods. Structure observation was made after surface preparation by light microscope. Findings: Research cobalt alloys are characterized by a dendritic crystals in structure. For both cobalt alloys increasing the time of age hardening effect on growth of the corrosion resistance, especially to increase the potential for pitting initiation. Research limitations/implications: The research was carried out on samples, not on final elements. Practical implications: The research material is used on dentures, so it must characterize the corrosion resistance. Results of this work make up an information on what heat treatment parameters may be pay attention for two base cobalt alloys: Remanium 2000+ (Dentaurum) and Wirobond LFC (Bego). Originality/value: The paper presents influence the heat treatment of two base metal alloys used on dental prosthesis on corrosion resistance.

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The influence of saliva and its substitutes on corrosion of some implant alloys

Andrysewicz E.

Acta Mechanica et Automatica

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2013

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Vol. 7, no. 2

69--74

EN

The purpose of this paper is evaluation of the influence of human saliva and its substitutes on the corrosion re sistance of some implant alloys used in stomatology, which included: austenitic steel (316L), titanium alloy (Ti6Al4V), and cobalt alloy (CoCrMo). Corrosion studies were conducted by means of the potentiodynamic method with the application of the VoltaLab 21 kit with VoltaMaster 4 software. The reference electrode was a saturated calomel electrode (SCE), whereas the counter electrode was a platinum electrode. The results of conducted studies indicate an increased current density in the passive range on potentiodynamic curves of studied alloys in the envi- ronment of human saliva, and also in a commercial saliva solution – Mucinox. On the basis of conducted corrosion studies, it can be stated that in terms of corrosion resistance the developed saliva substitutes may constitute competitive solutions to commercial saliva substitutes. The prepared substitutes should be studied further from the perspective of practical application for patients. The original value of the paper is a proposition of new saliva substitutes.

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Digitization procedure of creating 3D model of dental bridgework reconstruction

Dobrzański L. A., Reimann Ł.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

469--476

EN

Purpose: The still growing patient requirements is concerned with aesthetics but also with strength of the prosthetic restorations. Resistance on stresses depends among others on the shape, so it is necessary to transfer the dentures of a physical model to a computer environment and a simulation of the work conditions. The aim of that work was to study the methodology of digitization of a plaster model into a numerical model, using CAD/CAM dental system and CAD application, which can be in a next step imported to ANSYS application in order to realize stress analysis. Design/methodology/approach: To realize the transfer of a physical model of the dental bridge to a computer environment the 3i Incise Renishaw scanner which saved the plaster model by a probe about 1 or 3 mm diameter, moved in the scanner arm and contacted with it was used. A scanned plaster mode was exported into STL file and then opened in DentCAD Delcam application. Using the CAD module the preparation line was marked, a pontic was orientated in a right position and connectors of the pillar teeth and the pontic. Geometry and the cross section of the connectors depend on the bridgework strength. A designed bridge reconstruction was imported to CAD application and there curves were firstly drawn, then changed into NURBS surfaces and finally surfaces were merged into one solid model. A ready model can be imported up to ANSYS software in order to realize the stress analysis. Findings: A prepared dental case from a physical one was changed into a numerical model in following steps: scanning a plaster model by a contact scanner, designing the bridgeworks in CAD dental software environment, importing in CAD application, building the solid model and at the end importing in ANSYS software. Selected digitization procedure let to make all engineering calculations and analysis without manufacturing the physical model, what considerably reduce cost of the research investigations. Practical implications: A realized work gave an information about possibilities of verification for a physical model of restoration and a numerical model which can be compared to results from software simulation of behaviour of the bridgework in different load cases. Originality/value: The paper presents that it is not necessary to have a physical reconstruction model, to check the resistance on stress because it is possible to use the CAD/CAM dental system to design the dentures and then modelling the boundary conditions and observe the stress analysis.

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Effect of age hardening on corrosion resistance and hardness of CoCrMo alloys used in dental engineering

Dobrzański L., Reimann Ł., Krawczyk C.

Archives of Materials Science and Engineering

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2012

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Vol. 57, nr 1

5-12

EN

Purpose: The goal of the study is to research the effect of various time of ageing on corrosion resistance, hardness and structures of Remanium 2000+ Co-Cr-Mo alloys used in prosthodontia. Design/methodology/approach: To investigation was prepared mould, cast in 1430°C and realized the heat treatment: solutioning in 1250°C by 3 hours and then ageing in 850°C by 4, 8, 16 and 24 hours. Electrochemical corrosion examination were made in water center which simulated artificial saliva environment. The evaluation of breakdown potential was realized by recording of anodic polarization curves with use the potentiodynamic methods. Corrosion resistance test were carried out at room temperature and use of the VoltaLabŽ PGP201 system for electrochemical tests. Hardness test were obtained by use the microhardness FM ARS 9000 FUTURE TECH with load 1 kg. Structure observation was made after surface preparation: grinding, polishing and etching by light microscope LEICA MEF4A with the magnification 500x. Findings: The age hardening for Co-Cr-Mo alloys is one of the possible method which effect in forming the hardness. The highest value of hardness were obtain for specimen which was ageing with the longer time. Research alloy characterized dendritic crystals in structure for all realized heat treated process. At specimen after the longer ageing was observed the most of discontinuous precipitation and stacking faults in compare with specimen ageing by 4 hours. The age hardening doesn’t influenced much on electrochemical results and only the open circuit potential changed by decreased while increased ageing time. The values of breakdown potential and repassivation potential kept at a constant level. Practical implications: Research material is used on dentures so it’s demand that their characterized corrosion resistance and result of this work make up an information on what heat treatment parameters may be pay attention for CoCrMo alloys. Originality/value: The paper present effect of age hardening especially the ageing time, on the most important criteria of CoCrMo alloys use in dental engineering.

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Influence of Cr and Co on hardness and corrosion resistance CoCrMo alloys used on dentures

Dobrzański L. A., Reimann Ł.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

193--199

EN

Purpose: The goal of the study is to try find the relationship between cobalt content on hardness and chromium content on corrosion resistance on the basis of base cobalt alloys CoCrMo used in prosthodontia. Design/methodology/approach: To investigation was choose five base cobalt alloys with different concentration of cobalt and additions. Hardness test were obtained by use the microhardness FM ARS 9000 FUTURE TECH with load 1 kg. Structure observation was made after surface preparation by light microscope LEICA MEF4A with the magnification range 100-1000x. Corrosion resistance test were carried out at room temperature and use of the VoltaLab® PGP201 system for electrochemical tests. The examination were made in water center which simulated artificial saliva environment. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with use the potentiodynamic methods. Findings: The cobalt content in CoCrMo alloys in one of the possible parameters which influence on hardness. The highest value of hardness were obtain for alloy with the highest Co content. All of the research alloys characterized dendritic crystals in structure. Chromium content in one of the most important factor which influence on corrosion resistance, due to that alloy with the highest Cr content characterized the higher repassivation potential. Practical implications: Research materials are used on dentures so it’s demand that their characterized corrosion resistance and result of this work make up an information on what element should be pay attention in chemical composition of CoCrMo alloys. Originality/value: The paper present influence of chemical composition especially cobalt and chromium, on the most important criteria CoCrMo alloys use on dentures.