Marginal adaptation of amalgam and resin composite restorations in Class II conservative preparations.
OBJECTIVE
The purpose of this study was to compare and contrast the performance, in terms of marginal adaptation, of a non-gamma-2 amalgam alloy with a compact-filled light-cured composite in the restoration of Class II preparations of conservative design.


METHODS
Fifty recently extracted teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy, Dispersalloy, or a compact-filled resin composite, Z100, using standard techniques. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed at magnification x30.


RESULTS
Highly significant differences were demonstrated in the mean percentages of perfect margins in all 3 segments of the proximal boxes of the restorations with the resin composite performing significantly better than the amalgam. The percentages of marginal fissuring were significantly higher in the amalgam restorations, except at the cervical margin, where the incidence of fissuring was almost the same for the amalgam and resin composite restorations. The resin composite restorations had significantly fewer underfilled margins than the amalgam restorations.


CONCLUSIONS
In the conservative Class II preparations, the amalgam restorations were of poor quality with respect to marginal adaptation, compared with the resin composite restorations. It is suggested that the use of amalgam as a control in a clinical evaluation of resin composite restorations in conservative preparations cannot be justified, because it is apparently not possible to compare restorations of equivalent initial quality.
Duncalf
W V
WV
University Dental Hospital of Manchester, Higher Cambridge Street, Manchester M15 6FH, England.
Wilson
N H
NH
D001641:Bicuspid; D003188:Composite Resins; D003722:Dental Alloys; D003723:Dental Amalgam; D003737:Dental Cavity Preparation; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D006801:Humans; D008963:Molar; D012107:Research Design; D012822:Silicon Dioxide; D015040:Zirconium
D003188:Composite Resins; D003722:Dental Alloys; C083568:Z100 composite resin; C033470:Dispersalloy; D012822:Silicon Dioxide; D003723:Dental Amalgam; D015040:Zirconium