Characterization of two Ni–Cr dental alloys and the influence of casting mode on mechanical properties

Bauer, José; Costa, José Ferreira; Carvalho, Ceci Nunes; Loguércio, Alessandro Dourado; Reis, Alessandra

doi:10.1016/j.jpor.2012.02.004

Cited by 19 publications

(10 citation statements)

References 31 publications

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“…Due to the different microhardness values of the alloys, the resultant roughness of this airborne particle abrasion may be different for each type of alloy. However, several studies have shown that some of these alloys have very close microhardness values (9,24,25) and in the present study, different bond strength values were found with the same resin cement.…”

Section: Resultscontrasting

confidence: 46%

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement

et al. 2012

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The aim of this study was to evaluate the influence of microstructure and composition of basic alloys on their microshear bond strength (µSBS) to resin luting cement. The alloys used were: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Five wax patterns (13mm in diameter and 4mm height) were invested, and cast in a centrifugal casting machine for each basic alloy. The specimens were embedded in resin, polished with a SiC paper and sandblasted. After cleaning the metal surfaces, six tygon tubes (0.5 mm height and 0.75 mm in diameter) were placed on each alloy surface, the resin cement (Panavia F) was inserted, and the excess was removed before light-curing. After storage (24 h/37°C), the specimens were subjected to µSBS testing (0.5 mm/min). The data were subjected to a one-way repeated measures analysis of variance and Turkey's test (α=0.05). After polishing, their microstructures were revealed with specific conditioners. The highest µSBS (mean/standard deviation in MPa) were observed in the alloys with dendritic structure, eutectic formation or precipitation: VB (30.6/1.7), TS (29.8/0.9), SC (30.6/1.7), with the exception of IPS (31.1/0.9) which showed high µSBS but no eutectic formation. The W9 (28.1/1.5), VBII (25.9/2.0) and RM (25.9/0.9) showed the lowest µSBS and no eutectic formation. It seems that alloys with eutectic formation provide the highest µSBS values when bonded to a light-cured resin luting cement.

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Section: Resultscontrasting

confidence: 46%

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement

et al. 2012

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“…This phase presumably has been formed via a solid state reaction during cooling and should correspond to the intermetallic NiBe phase, based on the work of Hero et al 14 . Thus, the presence of this very characteristic eutectic is also a microstructural evidence of beryllium in the Ni-Cr base alloys, in agreement with results found in other papers 12,[14][15][16] . Bauer et al 15 found a lamellar eutectic in the microstructure of a certain alloy and suggested the possible existence of Be in its composition, although the manufacturer claimed the absence of Be in that alloy.…”

Section: Resultssupporting

confidence: 92%

Microstructural evidence of beryllium in commercial dental Ni-Cr alloys

et al. 2014

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The focus of this work was to determine microstructural features in commercial Ni-Cr alloys which could be used to identify indirectly the presence of beryllium. Thus, eight commercial alloys were characterized by chemical analysis, thermal analysis, X-ray diffraction (XRD), scanning electron microscopy -back-scattered electron images (SEM/BSE), energy-dispersive spectroscopy (EDS). The results indicate that the presence of beryllium can be inferred from microstructural analysis via XRD and SEM/BSE. The X-ray diffractograms of the beryllium-containing alloys showed clearly the existence of the NiBe intermetallic phase. SEM/BSE images of these alloys show a very characteristic eutectic microstructure which also indicates the presence of this element. These characteristics are not observed in the beryllium-free alloys.

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“…Sheet-like material samples with dimensions of 10 mm × 10 mm × 2 mm were prepared in accordance with the manufacturers’ recommendations using a laboratory lost wax technique [15]. Before corrosion testing, all samples were ground with 180-, 320-, and 600-grit Si carbide abrasive papers and then polished with 9-, 3-, and 0.05-μm diamond suspensions (Buehler, Germany) to produce mirror-like surfaces.…”

Section: Methodsmentioning

confidence: 99%

Corrosion of dental alloys in artificial saliva with Streptococcus mutans

Zheng

Zhong

2017

PLoS ONE

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A comparative study of the corrosion resistance of CoCr and NiCr alloys in artificial saliva (AS) containing tryptic soy broth (Solution 1) and Streptococcus mutans (S. mutans) species (Solution 2) was performed by electrochemical methods, including open circuit potential measurements, impedance spectroscopy, and potentiodynamic polarization. The adherence of S. mutans to the NiCr and CoCr alloy surfaces immersed in Solution 2 for 24 h was verified by scanning electron microscopy, while the results of electrochemical impedance spectroscopy confirmed the importance of biofilm formation for the corrosion process. The R(QR) equivalent circuit was successfully used to fit the data obtained for the AS mixture without S. mutans, while the R(Q(R(QR))) circuit was found to be more suitable for describing the biofilm properties after treatment with the AS containing S. mutans species. In addition, a negative shift of the open circuit potential with immersion time was observed for all samples regardless of the solution type. Both alloys exhibited higher charge transfer resistance after treatment with Solution 2, and lower corrosion current densities were detected for all samples in the presence of S. mutans. The obtained results suggest that the biofilm formation observed after 24 h of exposure to S. mutans bacteria might enhance the corrosion resistance of the studied samples by creating physical barriers that prevented oxygen interactions with the metal surfaces.

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Characterization of two Ni–Cr dental alloys and the influence of casting mode on mechanical properties

Abstract: The Ni-Cr-Mo-Ti alloy showed high UTS, MHV and lowest EL comparaded with the tradicional Ni-Cr-Mo-Be, that show lowest UTS, MHV and higher EL when cast on induction/argon.

Cited by 19 publications

References 31 publications

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement

Microstructural evidence of beryllium in commercial dental Ni-Cr alloys

Corrosion of dental alloys in artificial saliva with Streptococcus mutans

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