Clinical evaluation of four amalgam alloys: A five-year report

Doglia, R; Herr, P; Holz, J; Baume, Louis J.

doi:10.1016/0022-3913(86)90378-1

Cited by 18 publications

(3 citation statements)

References 13 publications

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“…In a clinical trial on three alloys, Osborne et al (1980a) showed that after eight years the amalgam alloy had a significant influence on the survival rate of amalgam restorations due to bulk fracture. Similar studies have been done with different alloys and follow-up times, but with the same results (Doglia et al, 1986;Letzel et al, 1989;Van Dijken, 1991). The results of the four studies are summarized in Table 1.…”

Section: Introductionsupporting

confidence: 71%

The Influence of the Amalgam Alloy on the Survival of Amalgam Restorations: A Secondary Analysis of Multiple Controlled Clinical Trials

Letzel

Hof²,

Marshall

et al. 1997

J Dent Res

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Data from 14 independent controlled clinical trials on the oral behavior of Classes 1 and 2 amalgam restorations, with a follow-up between five and 15 years, were re-evaluated by secondary analysis for the influence of alloy composition on the survival of amalgam restorations. For the analysis, 3119 restorations were available, which were made from 24 different alloys by a group of seven operators. The alloys were divided into four groups according to their zinc content (zinc-containing and zinc-free) and their copper content (conventional and high-copper). During the follow-up of the trials, the restorations were annually assessed for failures, which were classified as to (1) restoration-, (2) restorative process-, and (3) patient-related reasons. With the restoration-related failures, survival functions of the restorations were estimated by alloy and alloy group. The total number of failed restorations was 481, of which 77% were restoration-related and 14% process-related. Eighty percent of the restoration-related failures were due to some form of fracture of the amalgam. Restorations of conventional zinc-free alloys had the shortest survival. After 13 years, only 25% survived. Zinc and a high copper content had an equally favorable influence on the survival rate, which was 70% after 13 years when either was present. The highest survival rates were of restorations of zinc-containing high-copper alloys: 85% after 13 years. The zinc and copper contents of the alloy contributed to the corrosion resistance of the amalgams, which in turn influenced the survival of the restoration. The current ISO Standard 1559 on alloys for dental amalgam should be modified to account for these factors that influence the survival of amalgam restorations.

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Section: Introductionsupporting

confidence: 71%

The Influence of the Amalgam Alloy on the Survival of Amalgam Restorations: A Secondary Analysis of Multiple Controlled Clinical Trials

Letzel

Hof²,

Marshall

et al. 1997

J Dent Res

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“…An article by Doglia et al (1986) showed photomicrographs of replicas of amalgam alloy margins after two years of clinical service. The margins appeared to contain fracture lines roughly paralleling the margin.…”

mentioning

confidence: 99%

Amalgam Margin Breakdown Caused by Creep Fatigue Rupture

Williams

Cahoon

1989

J Dent Res

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This study was designed to determine whether the mechanical cyclic stressing that occurs during normal mastication contributes to margin breakdown of dental amalgam restorations. The method used appears to duplicate the mechanical stresses developed in vivo during mastication, as the result of tooth flexing. We evaluated one low-copper alloy--NTD--and three high-copper alloys--Dispersalloy, Phasealloy, and Tytin. We prepared simple amalgam restorations in a cavity centrally located in an aluminum beam. Each specimen received five periods of three-point cyclical loading (1.7 hertz, 4200 cycles at 37 degrees C). The margin area was subjected to SEM examination prior to and at the completion of each period of cycling. At the beginning of each period of cycling, beam deflection was set to establish a maximum theoretical stress of 1, 2, 4, 6, or 8 MPa. For all brands, cycling resulted in margin gap formation and surface wrinkling. Wrinkling in Dispersalloy occurred as a wide band of shallow wrinkles, whereas that in NTD occurred as a narrow band of deep wrinkles. At 21,000 cycles, very little void formation and fracturing had occurred in the Dispersalloy or NTD restorations. In contrast, the Phasealloy and Tytin restorations developed extensive fracturing even after 4200 cycles. Fracture surface analyses of Phasealloy and Tytin indicated that creep fatigue rupture was the fracture mechanism responsible for margin breakdown in these amalgam restorations, when subjected to cyclic compressive loading similar to that experienced during mastication.

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“…In einer kontrollierten klinischen Studie fand Doglia [11] Klasse-I-Amalgamfüllungen fest, während sich die Ergebnisse für Kavitäten der Klasse II zwischen 7 und 11 Jahren bewegten. Zweiflächige Amalgamfüllungen zeigten eine längere orale Verweildauer als 3-oder 4-flächige Restaurationen.…”

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