Physical properties of dental silver-tin amalgams with high and low copper contents

Malhotra, Manohar L.; Asgar, Kamal

doi:10.14219/jada.archive.1978.0100

Cited by 27 publications

(9 citation statements)

References 8 publications

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“…Values reported in the recent literature Malhotra and Asgar, 1978;Eames and MacNamara, 1976;Paffenbarger et al, 1979) reveal that amalgams either expand or contract slightly during setting. The current ADA specification #1 for dental amalgam permits a dimensional change of up to + 0.2% during setting.…”

Section: Methodsmentioning

confidence: 86%

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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Section: Methodsmentioning

confidence: 86%

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

Williams

Hedge

1985

J Dent Res

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“….4kad~miai Kiad6, Budapest negative or positive depending on the amount of mercury remaining and on the type of the alloy particles [7][8][9]. In general, previous dimensional change measurements on dental amalgams have led to controversial results.…”

Section: John Wiley and Sons Limited Chichestermentioning

confidence: 99%

Isothermal dimensional changes of some dental materials

Elhadary

Kamar

El-Kady

et al. 1989

Journal of Thermal Analysis

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The isothermal dimensional changes of four types of dental amalgams during the setting and for the next 24 hours after condensation have been studied by means of a Heraeus TA 500 thermal analysis system. The four types of dental amalgams w~re the lathe-cut conventional lowcopper amalgam (Amalcap), the spherical conventional low-copper amalgam (SpheraUoy), the ternary unicomposition high-copper amalgam (Sybralloy) and the admixed high-copper (Dispersalloy) amalgam.The dimensional changes of the four types of amalgams are explained on the basis of their particle sizes and shapes and their constitutions.

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“…It is believed that dental silver amalgam has served the profession well and will continue to do [3]. There are several documented physicochemical test procedures as requirements in the standards [4]. The appropriate mechanical properties have been specified as one of the important requirements, because the amalgam must resist the biting forces of occlusion [5].…”

Section: Introductionmentioning

confidence: 99%

Effect of setting time and artificial saliva on the strength evaluated by different methods of dental silver amalgam: A comparative study

Mohammadi

Mesgar

Rahmdar

et al. 2019

Materialwissenschaft Werkst

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The aim of this study is to evaluate the effect of setting time and artificial saliva on the strength of dental amalgam by diametral compressive strength, Hertzian failure loading testing and compressive strength test methods. Nine dental amalgam products are evaluated using three strength measurements, compressive, diametral, and Hertzian loading testing at early (1 h or 2 h), 24 h and 30 days after setting at 37 °C. The trituted amalgams are used to prepare Hertzian, tapered disc by manual condensation according to the ISO standard procedure (ISO 17988: 2014). The compressive and diametral testing specimens are obtained using the mechanical condensation by two apparatus with different specimen dimensions of height and diameter, 8.0 mm×4.0 mm and 2.0 mm×8.0 mm, respectively. The apparatus and schedule specification for preparing compressive testing specimens are according to ISO 24234: 2015 while dimensions of some parts of diametral testing apparatus were modified and the schedule was optimized to provide sound disc test‐pieces by a one‐shot procedure. The diametral and Hertzian testing specimens are also evaluated after 30 days under dry storage conditions and after aging in the artificial saliva. The artificial saliva was prepared according to ISO17988: 2014 standard specifications. The single diametral or “triple‐cleft” fracture path, and radial cracking are observed in all products for diametral and Hertzian testing methods, respectively. The discriminatory power in early strength tests is in order to Hertzian < diametral < compressive. A significant correlation between diametral and compressive strength value is observed at early setting time. It is found a correlation between diametral and Hertzian strength mean value and variance ratio in immersion test.

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Physical properties of dental silver-tin amalgams with high and low copper contents

Cited by 27 publications

References 8 publications

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

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

Isothermal dimensional changes of some dental materials

Effect of setting time and artificial saliva on the strength evaluated by different methods of dental silver amalgam: A comparative study

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