13-year clinical assessment of 10 amalgam alloys

Osborne, John W.; Norman, Richard D.

doi:10.1016/0109-5641(90)90028-d

Cited by 36 publications

(12 citation statements)

References 10 publications

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“…The reduction of cusp stiffness as a function of the volume of tooth tissue removed has been documented (Hood, 1991). The increase in marginal fracture found in connection with increased cavity size further supports the hypothesis that increased flexibility of the axial walls induces more fracture of the amalgam margins (Derand, 1977, de Vree et al, 1984Laswell et al, 1990;Osborne et al, 1991). One important finding by lokstad (1992) was that the smallest restorations (< 3 mm3) performed significantly better than larger restorations (> 6 mm3) at 6 months, 1 year, and 3 years, with respect to marginal fracture.…”

supporting

confidence: 57%

“…This feature has also been noted in other clinical trials, where the investigators reported differences between amalgam alloys after a relatively short observation period, with no relative changes thereafter (Ricker and Greener, 1988). Even after 13-14 years, the clinical performance ranking of amalgam alloys was identical to the one-year ranking (Osborne and Norman, 1990;Osborne et al, 1991). This signifies that at least one process which causes marginal fracture occurs during the first year after placement of the restoration.…”

mentioning

confidence: 66%

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Determinants of Quality in Operative Dentistry

Söderholm

Tyas

Jokstad

1998

Critical Reviews in Oral Biology & Medicine

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The definition of quality in operative dentistry has often, at least in part, been related to how well a cut preparation compares with an ideal preparation. The ideal preparation follows well-defined design principles. These design principles have their roots in empirical dentistry and scientific evaluations, the latter often being conducted in vitro. Because of the complexity of following these design principles practically, a large portion of dental education consists of perfecting cavity preparations. By focusing on how to cut these cavity preparations as closely as possible to the ideal preparation, dentists with high psycho-motor skills have been able to provide the public with restorative procedures of high standards over the years. However, because of the tendency of relating quality in operative dentistry to the ideal preparation, we found it justifiable to review the literature dealing with the cavity design principles of the Class II amalgam preparation. What triggered this review was a request from the International Dental Federation (FDI) to start a process leading to a scientifically based quality definition of dental restorations, a definition that determines how different factors, including cavity design principles, affect the longevity of both tooth and restoration. From our review, we conclude that patient response and restoration performance over time, rather than how closely a cavity preparation compares with the ideal preparation, will be of more significance in determining the longevity of a Class II amalgam restoration.

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supporting

confidence: 57%

mentioning

confidence: 66%

Determinants of Quality in Operative Dentistry

Söderholm

Tyas

Jokstad

1998

Critical Reviews in Oral Biology & Medicine

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“…This improvement has been demonstrated frequently in clinical trials (Osborne and Norman, 1990): Restorations of high-copper alloys have less marginal fracture than those of conventional alloys (Mahler et al, 1970). However, the improvement has a temporary effect on survival, because after about six years, the survival rate starts to decline.…”

Section: Survivalmentioning

confidence: 93%

“…The comparison of the two types of studies has led to much confusion in discussions on the survival of amalgam restorations (Osborne and Norman, 1990).…”

Section: Survivalmentioning

confidence: 99%

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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“…We have made vast improvements in the past 20 years with the development of the high-copper amalgams. Clinical studies initiated in the mid-1970s at Indiana (Osborne & Norman, 1990 Dentists recognize that mercury vapor is released from amalgams. The question is not if, but how much.…”

Section: John W Osbornementioning

confidence: 99%

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1991

Operative Dentistry

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13-year clinical assessment of 10 amalgam alloys

Cited by 36 publications

References 10 publications

Determinants of Quality in Operative Dentistry

Determinants of Quality in Operative Dentistry

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

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