Marginal fit of porcelain-fused-to-metal and two types of ceramic crown.

The marginal fit of Dicor, Cerestore, and porcelain-fused-to-metal crowns was evaluated. Ten premolars free of caries were prepared for each type of restoration and crowns were made. The vertical marginal openings were measured before cementation, after cementation, and after thermocycling. There were statistically significant differences between all three test conditions in each type of crown, between Dicor and porcelain-fused-to-metal crowns after cementation and after thermocycling, and between Cerestore and porcelain-fused-to-metal crowns after thermocycling. All 30 cemented crowns were then embedded in acrylic resin for serial sections for measurement of absolute marginal openings. Statistically significant differences between Dicor and Cerestore crowns and between Cerestore and porcelain-fused-to-metal crowns were found. It was concluded that marginal openings increased after cementation and after thermocycling, and porcelain-fused-to-metal crowns had significantly better marginal fit than that of Dicor and Cerestore crowns.