A Pd-free high gold dental alloy for porcelain bonding

Wang, JN; Liu, WB

doi:10.1007/bf03215538

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…In the case of alloys with a high gold content, they have a soft surface by poor hardness after casting, which leads to poor properties for processing, such as overlapping on the surface after grinding, resulting in the formation of porosity at the metal-ceramic interface [6]. Therefore, several studies have been performed to improve the hardness of the casted high-gold-content alloy for bonding porcelain by proper heat treatment prior to processing and porcelain firing [7,8]. Compared to the high-gold-content alloy, the low-gold-content alloy for bonding porcelain is much harder after casting, which also makes processing difficult or time consuming.…”

Section: Introductionmentioning

confidence: 99%

Change in hardness of an as-cast and softening heat-treated low-gold-content alloy for bonding porcelain by simulated porcelain firing and its mechanism

Kim

Kwon

et al. 2015

Gold Bull

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This study examined the change in hardness of a low-gold-content alloy for bonding porcelain induced by simulated porcelain firing after casting and softening heat treatment along with its mechanism. In the as-cast specimen, the hardness was increased by oxidation, and as the specimen underwent a further porcelain-firing process, the hardness decreased gradually to be softer than the as-cast state. The hardening in the as-cast specimen by oxidation was induced by the grain interior precipitation of the ordered Pd 3 (Sn,In) phase, which resulted in the formation of severe lattice strain in the matrix. Softening by the complete firing process in the as-cast specimen was due to the coarsening of the ordered Pd 3 (Sn,In) precipitates, which resulted in release of lattice strain by the reduced interphase boundaries between the coarsened precipitates and surrounding matrix. In the softening heat-treated specimen before simulated porcelain firing, the decrease in hardness by the softening heat treatment, which was performed to allow easy alloy processing before porcelain firing, was almost recovered in the oxidation-treated state, which is the first stage of the porcelain-firing cycles. From the first opaque-treated state, there was little difference between the hardness of the as-cast specimen and softening heat-treated specimens. The mechanism of hardening by oxidation and subsequent softening by the complete firing process was unaffected by the softening heat treatment before porcelain firing in a low-gold-content alloy for bonding porcelain.

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Section: Introductionmentioning

confidence: 99%

Change in hardness of an as-cast and softening heat-treated low-gold-content alloy for bonding porcelain by simulated porcelain firing and its mechanism

Kim

Kwon

et al. 2015

Gold Bull

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“…Koike reported that if a casting is pre-heated near the porcelain firing temperature before surface grinding, distortion from subsequent procedures can be controlled remarkably [7]. Liu and Wang reported that pre-firing heat treatment increased the hardness of Pd-free Au-Pt metal-ceramic gold alloy [8]. They attributed the strengthening to the homogenization of the microstructure and the precipitation of new fine particles.…”

Section: Introductionmentioning

confidence: 99%

“…This causes serious problems, such as an inaccurate fit of the restoration [5,6]. To resolve this problem, studies of heat treatments before porcelain firing have been conducted with a purpose to increase the hardness of metal-ceramic gold alloys before porcelain firing [7][8][9]. Koike reported that if a casting is pre-heated near the porcelain firing temperature before surface grinding, distortion from subsequent procedures can be controlled remarkably [7].…”

Section: Introductionmentioning

confidence: 99%

Hardening effect of pre- and post-firing heat treatment for a firing-simulated Au-Pd-In metal-ceramic alloy

Jeon

Kim

et al. 2014

Gold Bull

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The hardening effect of the pre-and post-firing heat treatments and their dual treatment was examined for a firingsimulated Au-Pd-In metal-ceramic alloy to determine if an additional post-firing heat treatment is effective in the hardening of an Au-Pd-In metal-ceramic alloy as well as to compare the hardening effects of pre-and post-firing heat treatments for a firing-simulated Au-Pd-In metal-ceramic alloy. The postfiring heat treatment was much more effective than the prefiring heat treatment or dual treatments. The hardening effect of the pre-and post-firing heat treatments was caused by the induction of fine grain interior precipitation. In the pre-firing heat-treated specimen after casting, the apparent hardening was achieved during simulated porcelain firing, but an additional post-firing heat treatment did not introduce severe grain interior precipitation, resulting in very weak hardening. In the as-cast specimen without the pre-firing heat treatment, apparent hardening by grain interior precipitation was achieved only by post-firing heat treatment and not by simulated porcelain firing.

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“…In the present case, Pt, Zn, Rh and Ir atoms are of a smaller size compared to Au atoms. Therefore, they cause a contraction of the crystal lattice leading to a substitutional solid-solution strengthening of Au [23,24]. This fact is reflected in the reduction of 0.00098 nm for the α 1 matrix lattice parameter in Au-Pt I alloy, compared to pure Au [2].…”

Section: Discussionmentioning

confidence: 99%

Microstructural analyses of two high noble gold-platinum alloys before and after conditioning in a cell culture medium

et al. 2010

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Microstructures of two high noble experimental Au-Pt alloys were compared before and after conditioning for biocompatibility, in order to identify phases and microelements responsible for the alloys' corrosive behaviour. Microstructural characterization was carried-out by optical and scanning electron microscopy, in addition to energy dispersive X-ray analysis. X-ray diffraction was applied to determine the phases' composition and their contribution in the alloys. Additionally, simultaneous thermal analysis was used to identify the temperatures of phase transformations. An overall assessment before conditioning showed that Au-Pt I is a two-phase alloy containing a dominant Au-rich α 1 phase and a minor Pt-rich α 2 phase, while the Au-Pt II alloy contains in addition three minor phases: AuZn 3 , Pt 3 Zn and Au 1.4 Zn 0.52 . The highest content of Zn (up to 6.76 wt.%) was detected in the Pt 3 Zn phase. After RPMI cell culture medium conditioning, the Pt 3 Zn and AuZn 3 phases disappeared, suggesting that they are predominantly responsible for Zn loss and the lower corrosive stability of the Au-Pt II alloy.

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A Pd-free high gold dental alloy for porcelain bonding

Cited by 12 publications

References 10 publications

Change in hardness of an as-cast and softening heat-treated low-gold-content alloy for bonding porcelain by simulated porcelain firing and its mechanism

Change in hardness of an as-cast and softening heat-treated low-gold-content alloy for bonding porcelain by simulated porcelain firing and its mechanism

Hardening effect of pre- and post-firing heat treatment for a firing-simulated Au-Pd-In metal-ceramic alloy

Microstructural analyses of two high noble gold-platinum alloys before and after conditioning in a cell culture medium

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