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Contact Dermatitis Mar 1993Palladium is increasingly used in industry, but also in fine jewelry and in dentistry. Thus, palladium-silver alloys comprise a substantial part of the noble metal...
Palladium is increasingly used in industry, but also in fine jewelry and in dentistry. Thus, palladium-silver alloys comprise a substantial part of the noble metal ceramic alloy sales in Western countries. The increased use of this metal seems, however, to be paralleled by a rise in the number of reports of palladium allergy. Recently a European study reported a sensitization rate of 2.8%. In Austria, where palladium has started to displace amalgam in dental fillings because of concerns about mercury toxicity, and gold due to price factors, we have found a sensitization rate of 8.3% in unselected eczema patients. Despite the current lack of clear clinical relevance of this finding, these numbers should motivate us to question this substance as "the alloy of the future".
Topics: Burning Mouth Syndrome; Dental Alloys; Dermatitis, Allergic Contact; Humans; Nickel; Palladium
PubMed: 8462294
DOI: 10.1111/j.1600-0536.1993.tb03379.x -
Dental Materials Journal Jun 2005In this study, the grindability of cast magnetic alloys (Fe-Pt-Nb magnetic alloy and magnetic stainless steel) was evaluated and compared with that of conventional... (Comparative Study)
Comparative Study
In this study, the grindability of cast magnetic alloys (Fe-Pt-Nb magnetic alloy and magnetic stainless steel) was evaluated and compared with that of conventional dental casting alloys (Ag-Pd-Au alloy, Type 4 gold alloy, and cobalt-chromium alloy). Grindability was evaluated in terms of grinding rate (i.e., volume of metal removed per minute) and grinding ratio (i.e., volume ratio of metal removed compared to wheel material lost). Solution treated Fe-Pt-Nb magnetic alloy had a significantly higher grinding rate than the aged one at a grinding speed of 750-1500 m x min(-1). At 500 m x min(-1), there were no significant differences in grinding rate between solution treated and aged Fe-Pt-Nb magnetic alloys. At a lower speed of 500 m x min(-1) or 750 m x min(-1), it was found that the grinding rates of aged Fe-Pt-Nb magnetic alloy and stainless steel were higher than those of conventional casting alloys.
Topics: Analysis of Variance; Chromium Alloys; Dental Alloys; Dental Polishing; Gold Alloys; Hardness; Iron; Magnetics; Materials Testing; Metallurgy; Microscopy, Electron, Scanning; Niobium; Platinum; Stainless Steel; Surface Properties
PubMed: 16022434
DOI: 10.4012/dmj.24.163 -
Acta Odontologica Scandinavica Feb 1984A silver-palladium type of dental alloy for fixed restorations has been investigated with regard to the ability of the material to be plastically deformed in uniaxial...
A silver-palladium type of dental alloy for fixed restorations has been investigated with regard to the ability of the material to be plastically deformed in uniaxial tensile testing after two different age-hardening treatments. A certain degree of ductility is required for the burnishing of the margins. Aged to peak hardness at 350 degrees C after solid-solution annealing at 900 degrees C, the material was found to be brittle owing to a reaction zone along the grain boundaries, promoting an intergranular fracture. When the age-hardening temperature was lowered to 275 degrees C, a less pronounced reaction zone along the grain boundaries could be observed. The accompanying mechanical properties after precipitation hardening at 275 degrees C are probably an acceptable compromise between mechanical strength and ductility. Small particles along grain boundaries and brittleness were also found after solid-solution annealing at 900 degrees C and quenching. It is suggested that the improved ductility after subsequent aging at 275 degrees C is due to a coarsening of these small particles. In the as-cast condition the alloy was softer and more ductile than in the age-hardened state.
Topics: Copper; Dental Alloys; Dental Stress Analysis; Gold Alloys; Metallurgy; Palladium; Silver; Temperature
PubMed: 6585123
DOI: 10.3109/00016358409041131 -
Journal of Biomedical Materials... Nov 2020A Co-Cr-Mo-C biomedical alloy was processed by investment casting, and its surface was modified using pulsed laser melting. The modified surface underwent rapid...
A Co-Cr-Mo-C biomedical alloy was processed by investment casting, and its surface was modified using pulsed laser melting. The modified surface underwent rapid solidification, and the exhibited microstructure as well as its corrosion properties were investigated. It was found that the laser surface modified (LSM) Co-Cr-Mo-C alloy possesses enhanced corrosion resistance when compared with the same alloy in the as-cast condition. Microstructural determinations indicated that the LSM Co-Cr-Mo-C alloy exhibited a lack significant solute segregation and a predominantly cellular morphology as a result of the development of a cellular solid-liquid front. The cellular morphology was characterized by a fine distribution of nano-scale M C carbides at the intercellular regions. Moreover, the austenite (γ) to athermal ε-martensite transformation was totally suppressed in the cellular solidified regions. In contrast, the as-cast alloy develops a coarse dendritic microstructure with coarse carbides in the interdendritic regions. Solute segregation is also present, as well as athermal ε-martensite (13 pct). It was found that the corrosion resistance of the LSM alloy in the Ringer solution exhibits improved corrosion potential and a reduced corrosion current density (-281 mV and 0.032 μA/cm , respectively),when compared with the same alloy in the investment as-cast condition (-356 mV and 0.150 μA/cm ).
Topics: Biocompatible Materials; Chromium Alloys; Corrosion; Dental Alloys; Hardness; Lasers; Materials Testing; Surface Properties; X-Ray Diffraction
PubMed: 32619316
DOI: 10.1002/jbm.b.34644 -
Journal of Biomedical Materials Research Nov 1974
Topics: Absorption; Dental Alloys; Diffusion; Radioisotopes; Silver; Temperature; Tin
PubMed: 4436340
DOI: 10.1002/jbm.820080606 -
Journal of Biomedical Materials Research Dec 2000Investigations in the binary system gold-titanium (Au-Ti) were performed in regard to the development of a universal dental alloy suited for inlays, for the conventional... (Comparative Study)
Comparative Study
Investigations in the binary system gold-titanium (Au-Ti) were performed in regard to the development of a universal dental alloy suited for inlays, for the conventional crown and bridge technique, as well as for the ceramic-fused-to-metal technique. With nine alloys with increasing Ti content from 0-10 atom %, microstructure, mechanical properties, thermal properties, and corrosion were determined in the as-cast state and after simulation of ceramic firing. The microstructure shows an increasing formation of a second phase with increasing Ti content, crystallizing dendritically, which, according to the binary phase diagram must be the intermetallic phase TiAu(4). The results of the measurements reveal that with increasing Ti content, hardness, Young's modulus, proof stress, and tensile strength strongly increase in the range of 2-6 atom % Ti and with higher Ti content remain constant. Elongation after fracture decreases with a Ti content above 2 atom %. The coefficient of thermal expansion decreases linearly with increasing Ti content. Thermal distortion decreases exponentially with increasing Ti content. The corrosion test showed an increasing release of Ti with increasing Ti content. Lowest corrosion was observed in the simulated state with intact oxide layer. Appropriate properties for dental application were found in the range of 6.5 at% Ti.
Topics: Ceramics; Chemical Phenomena; Chemistry, Physical; Corrosion; Crystallization; Dental Alloys; Elasticity; Gold; Hardness; Hot Temperature; Materials Testing; Microscopy, Electron; Tensile Strength; Titanium
PubMed: 11033550
DOI: 10.1002/1097-4636(20001215)52:4<678::aid-jbm12>3.0.co;2-p -
Journal of Dental Research 1959
Topics: Dental Alloys; Dental Materials; Gold; Gold Alloys; Hardness; Hot Temperature; Humans
PubMed: 14404034
DOI: 10.1177/00220345590380051801 -
Revue Belge de Medecine Dentaire.... 1978Corrosion of amalgam is a natural phenomenon of the behaviour of a metallic substance in the oral environment. Corrosion is a process in which we have a anodic reaction...
Corrosion of amalgam is a natural phenomenon of the behaviour of a metallic substance in the oral environment. Corrosion is a process in which we have a anodic reaction resulting in a loss of electrons and a cathodic reaction resulting in a captation of electrons. One single amalgam restoration in a electrolitic environment as the saliva shows areas acting as anode and others acting as cathode. Certain factors may influence the corrosion: they are the composition of the alloy, the particle size and form, the mercury content, the presence of more or less important quantity of gamma-2 phase, the degree of surface finishing, etc. It is likely that the dispersion phase alloy are more resistant to corrosion than the conventional alloys and that fluoridates amalgams are also more prone to corrosion.
Topics: Corrosion; Dental Alloys; Dental Amalgam; Mercury; Particle Size
PubMed: 291078
DOI: No ID Found -
Journal of Oral Rehabilitation Apr 1998The corrosion behaviour of an indigenous cast alloy of Ag-Sn-Cu, developed for crown and bridge prostheses, was studied in artificial saliva, with and without the... (Comparative Study)
Comparative Study
The corrosion behaviour of an indigenous cast alloy of Ag-Sn-Cu, developed for crown and bridge prostheses, was studied in artificial saliva, with and without the addition of 0.1 M lactic acid, using a potentiostatic technique, and compared with that of the standard cast alloy of Ag-Pd (Ney 76). The values of different parameters such as corrosion potential and corrosion current density were determined for the indigenous alloy of Ag-Sn-Cu and the Ag-Pd alloy. The rate of corrosion of the indigenous alloy was found to be relatively higher than that of the Ag-Pd alloy up to an applied potential of + 400 mV. However, while the indigenous alloy showed a distinct tendency for passivation below + 200 mV at the current level of 0.5 mA/cm2 in the artificial saliva (pH 5.7) at 37 degrees C, no such tendency for passivation was shown by the Ag-Pd alloy even up to + 400 mV. The tendency for passivation by the indigenous Ag-Sn-Cu alloy, however, was not shown in the artificial saliva in the presence of 0.1 M lactic acid (pH. 2.7) at 37 degrees C. Minor variation was observed in the corrosion behaviour of the indigenous Ag-Sn-Cu alloys of different grades prepared by alloying elements of varying purity.
Topics: Copper; Corrosion; Dental Alloys; Lactic Acid; Materials Testing; Microscopy, Electron, Scanning; Palladium; Saliva, Artificial; Silver
PubMed: 9610857
DOI: 10.1111/j.1365-2842.1998.00217.x -
Dental Clinics of North America Oct 1983The diversity of alloys available to the dental practitioner has never been more extensive. We now have the opportunity to select alloys based on the individual... (Comparative Study)
Comparative Study Review
The diversity of alloys available to the dental practitioner has never been more extensive. We now have the opportunity to select alloys based on the individual patient's specific biologic, functional, and economic requirements. There is no one alloy suitable for all applications, because in metallurgy there is a constant trade-off in properties as changes in formulations are made. To make optimal use of the choices available, and for ethical and medicolegal considerations, it is incumbent upon the practitioner to be aware of the identity and composition of the alloys prescribed.
Topics: Chemical Phenomena; Chemistry, Physical; Chromium Alloys; Dental Alloys; Dental Casting Investment; Dental Porcelain; Gold Alloys
PubMed: 6360731
DOI: No ID Found