In vitro Corrosion and in vivo Marginal Fracture of Dental Amalgams

Sarkar, N. K.; Osborne, John W.; Leinfelder, Karl F.

doi:10.1177/00220345820610111101

Cited by 35 publications

(6 citation statements)

References 22 publications

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“…The modest performance of grey cast iron is related to its ferritic-pearlitic matrix liable to graphitization damage. Corrosion index is a quantitative measure of corrosion susceptibility, related to the volume fraction of corrodible phases [9]. Corrosion index of high-Cr steel was 62.75% that of grey cast iron.…”

Section: Discussionmentioning

confidence: 99%

“…Cycling was repeated ten times, in order to allow for appreciable oxidation of metals, then the last cycle was recorded. The area under the potential-current curve was calculated by planimetry, in order to determine the corrosion index or the susceptibility of an alloy to corrosion under oxidationreduction (or corrosion-annihilation) conditions [9].…”

Section: Methodsmentioning

confidence: 99%

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Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel

Metwally

Samy

1994

Steel Research

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In order to evaluate the performance of high-Cr cast-steel (15.4% Cr), as a pump casing material, abrasive wear, hardness. corrosion, erosion-corrosion resistance were examined and compared with grey cast iron eventually used. The results obtained were analyzed on a microstructural basis with respect to Cr content of the matrix, amount and types of carbides and the extent of surface passivation. Martensitic high-Cr steel has shown a better performance than grey cast iron. Abschatzung des Widerstandes gegen AbrasivverschleiB und Erosionskorrosion fiir hochlegierten ChromstahlguB. Um die Eignung von hochlegiertem ChromstahlguB (15.4% Cr) als Werkstoff tor Pumpengehause abzuschatzen, wurden Harte, Korrosionsverhalten sowie der Widerstand gegen AbrasivverschleiB und Erosionskorrosion ermittelt. Die Oaten wurden mit denen tor GrauguB, der ebenfalls fur diese Anwendung infrage kame, verglichen. Neben dem Chromgehalt der Matrix, Menge und Typ der Carbide ist auch das AusmaB der Oberflachenpassivierung van Bedeutung. Die Ergebnisse fOhrten zu dem SchluB, daB martensitischer hochlegierter ChromstahlguB sich tor die genannte Anwendung besser als GrauguB eignet.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel

Metwally

Samy

1994

Steel Research

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“…As the marginal integrity of the amalgam restorations could depend largely on the mechanical properties of the amalgam margins after corrosion, a microhardness test of corroded amalgams could be a reliable method of predicting the long-term marginal performance of dental amalgam. Corrosion in vitro has been used to predict the clinical beha^or of dental amalgam (8), and various corrosive factors operating in the oral cavity have been recognized (9)(10)(11). Chloride ions have been shown to play a particularly important role in the corrosioD of amalgams (12,13).…”

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confidence: 99%

Marginal microhardness of corroded amalgams: a comparative in vitro study

Patsurakos

Moberg

1990

European J Oral Sciences

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– One conventional and two high‐Cu amalgams were tested for marginal microhardness after 2 months' corrosion in an 85 mM NaCl solution. Amalgams immersed in 200 mM phosphate buffer solution were used as controls. The microhardness tests were conducted on cross‐sections of the amalgams 50μm from the surface edges. The microstructure of the amalgams was studied in SEM and the amounts of Sn, Cu, Zn, Ag, and Hg dissolved in the solutions were analyzed with an atomic absorption spectrophotometer. For the amalgams immersed in the NaCl solution the depth of corrosion after 2 months was between 50 and 400μm. The specimens immersed in the phosphate solution showed no signs of subsurface corrosion. The marginal microhardness of all the amalgams was reduced after corrosion in the NaCl solution. The greatest microhardness in both the uncorroded and corroded states was shown in the two high‐Cu amalgams. The reduction in marginal microhardness after corrosion can probably be attributed mainly to degradation of the gamma‐2 phase for the conventional amalgam and to degradation of the η′ phase for the two high‐Cu amalgams.

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“…Corrosion, which is a suspected cause of amalgam failure (Sarkar, 1982;McTique, et al, 1984), would probably increase the rate of creep-fatigue failure of amalgam restoration margins. Corrosion enhances the rate of fatigue failure in metals (Cell and Leverant, 1973;Coffin, 1979Coffin, , 1983, and has been shown to increase the susceptibility of dental amalgam to fracture (Hera et al, 1983).…”

Section: Methodsmentioning

confidence: 99%

“…Although the gamma-2-free amalgams clinically demonstrate markedly improved resistance to marginal breakdown, they still experience corrosion and margin fracture (Duperon et al, 1971;Sarkar et al, 1982;McTique et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

Creep-fatigue as a Possible Cause of Dental Amalgam Margin Failure

Williams

Hedge

1985

J Dent Res

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Fracture of the margins is the most common cause of failure of dental amalgam restorations. Both corrosion and creep have been identified as possible contributors to this type of failure. The stresses that induce creep may arise from the continued setting expansion of the amalgam, the formation of corrosion products, mastication, or from the thermal expansion of the amalgam during ingestion of hot foods. The latter two are low-frequency cyclic stresses. The amalgams used in dentistry have fusion temperatures only about 40 degrees C above mouth temperature, and they experience grain boundary sliding during creep deformation. Since grain boundary sliding, low-frequency cyclic stresses, and a temperature near the fusion temperature of the alloy are prerequisites for so-called "creep-fatigue fracture", this type of fracture may contribute to amalgam margin failure. Amalgam made from seven different alloys was condensed into stainless steel dies. After being allowed to set for seven days, the specimens were thermally cycled between 4 degrees C and 50 degrees C for 500 and 1000 cycles. Amalgam margin integrity was evaluated by scanning electron microscopy both before and after each cycling period. The amount of margin fracture was calculated after 1000 cycles. Thermal cycling of amalgam restorations placed in stainless steel dies resulted in predominantly intergranular fracturing of the amalgam margins, indicating that creep-fatigue failure may be a significant contributor to in vivo margin fracturing.

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In vitro Corrosion and in vivo Marginal Fracture of Dental Amalgams

Cited by 35 publications

References 22 publications

Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel

Evaluation of abrasive‐wear and erosion‐corrosion resistance of high‐Cr cast‐steel

Marginal microhardness of corroded amalgams: a comparative in vitro study

Creep-fatigue as a Possible Cause of Dental Amalgam Margin Failure

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