scholarly journals Effect of recasting on the thickness of metal-ceramic interface of nickel-chromium and cobalt-chromium alloys

2008 ◽  
Vol 65 (5) ◽  
pp. 365-369 ◽  
Author(s):  
Nemanja Mirkovic ◽  
Miroslav Draganjac ◽  
Dragoslav Stamenkovic ◽  
Ljubisa Ristic
Keyword(s):  
Sem Analysis ◽  
Chromium Alloy ◽  
Interface Thickness ◽  
Cobalt Chromium ◽  
X Ray ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic ◽  
Negative Effect

Introduction/Aim. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the thickness of their metal-ceramic interface in making fixed partial dentures. Metal-ceramic interface determines their functional integrity and prevents damages on ceramics during mastication. Investigation of metal-ceramic samples is supposed to show if base metal alloys for metalceramics are successfully recycled without any risk of reduction of metal-ceramic interface thickness. Methods. The research was performed as an experimental study. Per six metal-ceramic samples of nickel-chromium alloy (Wiron99) and cobalt-chromium alloy (Wirobond C) were made each. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Analysis Energy Dispersive X-ray (EDX) (Oxford Instruments) and Scanning Electon Microscop (SEM) analysis (JEOL) were used to determine thickness of metal-ceramic interface together with PC Software for quantification of visual information's (KVI POPOVAC). Results. Results of this research introduced significant differences between thickness of metal-ceramic interface in every examined recycle generation. Recasting had negative effect on thickness of metal-ceramic interface of the examined alloys. This research showed almost linear reduction of elastic modulus up to the 12th generation of recycling. Conclusion. Recasting of nickel-chromium and cobaltchromium alloys is not recommended because of reduced thickness of metal-ceramic interface of these alloys. Instead of recycling, the alloy residues should be returned to the manufacturers.

scholarly journals Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (7) ◽  
pp. 469-473 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Testing Machine ◽  
Fracture Load ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic

Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C) were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464), with the speed of 0,05 mm/min. Results. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Conclusion. Recasting of nickelchromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer. .

scholarly journals EDX analyisis of metal-ceramic interfaces of recasted nickel-chromium dental alloys

2018 ◽  
Vol 72 (3) ◽  
pp. 149-156
Author(s):  
Vladimir Stefanovic ◽  
Zoran Lazic ◽  
Nemanja Mirkovic ◽  
Ervin Taso ◽  
Nenad Simeunovic ◽  
...  
Keyword(s):  
Intermediate Phase ◽  
Nickel Concentration ◽  
Detailed Knowledge ◽  
Chromium Alloy ◽  
Dental Alloys ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic ◽  
Ceramic Interfaces

This research was performed to establish recasting effects of nickel-chromium dental alloys on the composition of their metal-ceramic interface in making fixed partial dentures. The metal-ceramic interface determines denture functional integrity and prevents damages on ceramics during mastication. Recycling of nickel-chromium alloys is often a practice, without detailed knowledge about possible effects on the composition of the metal-ceramic interface. Investigation of metal-ceramic samples is intended to show if base metal alloys for metal-ceramics are successfully recycled without any composition change in the metal-ceramic interface. The research was performed as an experimental study in which six metal-ceramic samples of nickel-chromium alloy ?Wiron 99? (Bego, Germany) were made. Alloy residues were recycled through twelve casting generations with the addition of 50 wt% of the new alloy on the occasion of every recasting. EDX analysis was performed by using the ?Inca X Sight? apparatus (Oxford Instruments, UK) and a SEM device JSM 6460 LV (JEOL, Japan). This appliance was used in conjunction with the PC software for quantification of chemical elements in order to determine the composition of metal-ceramic interfaces. Results of this research revealed significant differences between compositions of metal-ceramic interfaces in every examined recycle generation. Recasting had a negative effect on alloy components, which concentration is decreasing in the metal-ceramic junction zone. The concentration of cerium in the intermediate phase decreased the most, followed by concentrations of niobium, molybdenum, nickel and chromium. Results showed a permanent reduction of metal components up to the 12th generation of recycling. Cerium concentration (wt%) decreased from 28 to 16.26 %, nickel concentration from 3.31 to 1.82 % and chromium concentration from 2.95 to 2.03 %. Similarly, the molybdenum content decreased from 8.71to 4.68 wt%, while that of niobium from 9.82 to 3.97 wt%. Therefore, recasting of nickel-chromium alloys is not recommended because of changed composition of the metal-ceramic interface of these alloys.

scholarly journals Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (4) ◽  
pp. 241-245 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Bond Strength ◽  
Testing Machine ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
Ceramic Bond ◽  
Metal Ceramic

Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimental study. Six metalceramic samples were made from nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C), according to the manufactures manuals and instructions from ISO 9693: 1996. Three-point bending test was performed up to the ceramic fracture. The fracture load was measured on an universal testing machine (Zwick, type 1464), with cross-head speed of 0,05mm/min. Results. The results of this study confirmed the significant differences between the metal-ceramic bond strength (p < 0.01) and elastic modulus (p < 0.001) of nickel-chromium and cobalt-chromium alloys, where cobalt-chromium alloys showed higher values for both tested parameters. Conclusion. Cobalt-chromium metal-ceramic alloys can successfully replace nickel-chromium alloys, especially for fabrication of long-span metal-ceramic bridges due to the great flexural strength.

scholarly journals X-ray spectral microanalysis of hardened additive products made of electroerosion cobalt-chromium alloys

2020 ◽  
Vol 329 ◽  
pp. 02014
Author(s):  
E.V. Ageeva ◽  
A.Yu. Altukhov ◽  
R A. Latypov ◽  
G.R. Latypova
Keyword(s):  
Iron Alloy ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Cocrmo Alloy ◽  
X Ray ◽  
Nickel Iron ◽  
Chromium Alloys ◽  
Electric Erosion ◽  
Nickel Iron Alloy ◽  
Cobalt Chromium Molybdenum

This article presents the results of an X-ray spectral microanalysis of cobalt-chromium alloys based on particles of the of the tungsten nickel iron alloy dispersed by electric erosion, obtained in alcohol. It has been experimentally proved that a part of oxygen is present in the cobalt-chromium alloy of particles of the cobalt-chromium-molybdenum alloy dispersed by electric erosion. All other elements are distributed relatively evenly over the volume of particles. It is shown that Co, Cr and Mo are the main elements of the (CoCrMo) alloy dispersed by electric erosion.

scholarly journals Bond strength of three dental porcelains to Ni-Cr and Co-Cr-Ti alloys

2006 ◽  
Vol 17 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Alfredo Julio Fernandes Neto ◽  
Heitor Panzeri ◽  
Flavio Domingues Neves ◽  
Ricardo Alves do Prado ◽  
Gustavo Mendonça
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Ti Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Ti Alloys ◽  
Chromium Alloys ◽  
Metal Ceramic

Ceramometal bond strength has played an important role for the replacement of gold alloys by nickel-chromium alloys in dentistry. This study evaluated the metal/porcelain bond strength of three ceramic systems (Vita VMK 88, Williams and Duceram) associated with three nickel-chromium alloys (Durabond, Lite Cast B and Resistal P) and one experimental cobalt-chromium-titanium alloy. Thirty cast cylinder specimens (15 mm in height; 6 mm in diameter) were obtained for each alloy, in away that 10 specimens of each alloy were tested with each porcelain. Bond strength was measured with an Emic screw-driven mechanical testing machine by applying parallel shear forces to the specimens until fracture. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis of the alloy/ceramic combinations (p<0.05). Resistal P/Duceram had significantly higher bond strength (44.38±9.12 MPa) (p<0.05) than the other combinations, except for Co-Cr-Ti alloy/Vita VMK 88 (38.41±12.64 MPa). The association of the experimental Co-Cr-Ti alloy with Williams porcelain had significantly higher bond strength (28.20±3.86 MPa) than the combination of other alloys with the same porcelain (p<0.05). Based of these results and within the limitations of an in vitro study, it may be concluded that the bond strength of the three ceramic systems to the Ni-Cr and Co-Cr-Ti alloys varied significantly, indicating that metal/ceramic compatibility was very important to the bond strength.

scholarly journals Evaluation of the Effect of recasting Nickel–chromium Base Metal Alloy on the Metal–ceramic Bond Strength: An in vitro Study

2017 ◽  
Vol 18 (9) ◽  
pp. 837-841
Author(s):  
T Meenakshi ◽  
Munagapati Bharathi ◽  
Jayasree Komala
Keyword(s):  
Bond Strength ◽  
Base Metal ◽  
Metal Alloy ◽  
Bending Test ◽  
Chromium Alloy ◽  
Nickel Chromium ◽  
Ceramic Bond ◽  
Metal Ceramic ◽  
Base Metal Alloy

ABSTRACT Aim The aim of this study was to evaluate the effect of recasting base metal alloy on the metal–ceramic bond strength. Materials and methods A total of 60 test samples were prepared from new and recast nickel–chromium alloy and divided into six groups. In group A0, test samples were prepared from 100% new alloy. Groups A1, A2, A3, A4, and A5 were prepared from 50% new alloy and 50% casting remnants (sprue and buttons) of the previous group by weight. All these samples were coated with ceramic (IPS d.SIGN and Ivoclar-Vivadent), and samples were then subjected to three-point bending test to evaluate metal–ceramic bond strength. Results The values were analyzed using one-way analysis of variance and Tukey's post hoc test. The mean bond strength of group A0 was higher than that of groups A1, A2, A3, A4, and A5. Conclusion Metal–ceramic bond strength decreased significantly with multiple recastings. Clinical significance Bond strength between metal and ceramic is a crucial factor for the clinical performance of metal–ceramic restorations. Recasting of alloys may affect the metal oxide layer composition and thickness of metal–ceramic interface, and thereby the metal–ceramic bond. How to cite this article Meenakshi T, Bharathi M, Komala J. Evaluation of the Effect of recasting Nickel–chromium Base Metal Alloy on the Metal–ceramic Bond Strength: An in vitro Study. J Contemp Dent Pract 2017;18(9):837-841.

The Effect of Cooling Times on the Bonding Between Porcelain and Metal Alloys Fabricated by Different Techniques: In Vitro Study

2021 ◽  
pp. 232020682110371
Author(s):  
Emine Ünal ◽  
Faik Tugut
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Laser Sintering ◽  
Cobalt Chromium ◽  
Slow Cooling ◽  
Ceramic Samples ◽  
Metal Framework ◽  
Metal Ceramic ◽  
Bond Strengths ◽  
Fast Cooling

Aim: The aim of this study was to evaluate the effect of different cooling times on shear bond strength between cobalt–chromium metal frameworks fabricated by different techniques and veneering porcelain. Materials and Methods: One hundred twenty cobalt–chromium metal ceramic samples were obtained by three different techniques (casting, milling, and laser sintering). During the porcelain firing, fast and slow cooling protocols were applied. Ten specimens from each group were determined for all groups. The shear bond strength of the metal ceramic samples was measured by a universal testing machine with a constant crosshead speed of 0.5 mm/min. One sample from each group was evaluated by the scanning electron microscopy analysis in terms of surface change and fracture morphology. Variance analysis and Tukey test were used to analyze statistically significant differences between groups. Results: It was seen that the difference between the bond strengths of the metal frameworks obtained by different techniques was statistically significant ( P < .05). All groups except for difference between the bond strengths of all the frameworks metal groups with G-Ceram porcelain were statistically significant ( P < .05). The best bond strengths that were statistically significant were fast cooling G-Ceram (19.65 ± 2.65 MPa) with metal frameworks fabricated by laser sintering, fast cooling with metal framework fabricated by milling Noritake (19.17 ± 2.91 MPa), and the metal framework fabricated by casting was found to be slow cooling Noritake (12.99 ± 2.08 MPa) were seen. Conclusion: The porcelain cooling times had significant effect on the shear bond strength of porcelain to casting, milling and laser sintering alloys.

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