• Journal of Technologic Dentistry
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• v.33 no.2
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• pp.121-128
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• 2011

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days ${\pm}$ 1 hour in the water tank of which temperature was $37^{\circ}C$. The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.6
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• pp.647-653
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• 2004

Statement of problem. The effects of various core buildup materials which differs in the mechanical properties on the fracture strength of metal-free crowns is unknown. Purpose. This study was carried out to evaluate the fracture strengths of Artglass ceromer crowns supported by 3 different core materials in clinically simulated anterior tooth preparation. Material and methods. Ten crowns from each group were constructed to comparable dimensions on the various dies made by gold alloy, Ni-Cr alloy, and composite resin. The ten crowns were then cemented onto the dies and loaded until catastrophic failure took place. Fracture resistance to forces applied to the incisal edges of the anterior crowns supported by three types of dies was tested. Results. The ceromer crowns on the composite resin dies fractured at significantly lower values(287.7 N) than the ceromer crowns on the metal dies(approximately 518.4 N). No significant difference was found between the fracture values of the ceromer crowns on the dies of gold alloy and Ni-Cr alloy. Conclusion. The failure loads of the ceromer crowns on the metal dies were almost the same and not affected by the differences of casting alloys. However, the fracture values of the ceromer crowns on the resin dies were significantly reduced by the relative weak properties of composite resin core material.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.3
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• pp.203-210
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• 2006

Although porcelain fused to metal crowns made from non-precious metal have good mechanical properties, they also have disadvantages such as the poor biological acceptability and the low corrosional resistance. Titanium is used as the alternative metal for porcelain fused to metal crowns, in spite of difficulties in casting. For that reason non-precious alloy including titanium which is easy to cast is currently used. This study evaluated the bond strength between non-precious alloy including titanium and Ni-Cr alloy. $Tilite^{(R)}V$ as non-precious alloy including titanium, $Rexilium^{(R)}V$ as Ni-Cr alloy and $Omega900^{(R)}$ and $Vintage(Regular)^{(R)}$ as porcelain powders were used. The results were as follows. 1. In comparison with the kind of alloy, the bond strength of $Tilite^{(R)}V$ was lower than that of $Rexilium^{(R)}V$. There was no significant difference between two groups. 2. In comparison with the kind of porcelain powder, the bond strength of $Omega900^{(R)}$ was higher than that of $Vintage(Regular)^{(R)}$ in $Tilite^{(R)}V$. There was significant difference between two groups(p < 0.05).

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.47-53
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• 1998

Radiant heater tubes with an inside burner are designed to transfer the heat generated from the burner to the outside of the tube by radiation. Hence, tube metal must suffer high temperature of approximately 900-$1000^{\circ}C$. The radiant tube is usually manufactured by centrifugal casting with high Ni-Cr alloys. In this study, failure analysis results of the radiant tube are reported. Failure mechanism of the tube was investigated by visual observation of the foiled tube, metallographic study of the cracked region and chemical analysis of tube metal and oxide scales. It was argued that the main cause of the cracking is repeated oxidation of the tube metal located beneath the thick oxide scale. Oxidation was caused by abnormally high operating temperature which can be verified by aged microstructure and internal void formation.