Marginal adaptation of crowns: a scanning electron microscopic investigation.

Most studies on marginal adaptation have been performed in vitro; only a few studies have investigated in vivo marginal adaptation and microleakage of crowns. In this study, gold crowns were prepared and cemented on abutments, and their marginal discrepancies were analyzed by scanning electron microscopy according to the impression-replica and cross-section methods. Three observers measured the marginal discrepancies of each crown. Interobserver variance of accuracy was 10 microns by the impression-replica and 15 microns by the cross-section method. The mean values were 124.16 microns by the impression-replica and 129.79 microns by the cross-section method. The two methods tested showed similar results.