Effect of fitting adjustments on compressive strength of a new foil crown system.

The effect of die spacing and precementation internal adjustments on the compressive strength of a new ceramic foil crown system was examined in vitro. Twenty-four ceramic foil crowns were made for identical stylized master dies made of polycarbonate filled with 30 wt% carbon. One half of the stone working dies were coated with die spacer and the remaining were left untreated. A special foil used for these crowns was adapted to the working dies under 2500 psi loading. A sculpturing device was used to standardize the size and shape of the ceramic foil crowns. Only crowns made on dies coated with die spacer received precementation fitting adjustment. All crowns in the two groups were cemented with zinc phosphate cement and were subjected to compressive force until fracture occurred. Compressive strength data were analyzed and compared. Results showed that the use of die spacer and internal adjustments increased the compressive strength of the new ceramic foil crown.