Effect of porcelain crown substructures on visually perceivable value.

Factors that will affect the potential color of ceramic restorations must be understood to control variables that exist. Clinical observations of porcelain restorations lead to the hypothesis that certain substructures tend to produce crowns with a lower than expected Value (brightness). This study was done to determine whether a visually perceivable difference could be detected between groups of ceramic crowns with different substructures. Two test groups of crown types with four different porcelain substructures were compared. In the first group, metal ceramic crowns made with either Galaxy or Rexillium III alloys were compared. In the second group, aluminous porcelain jacket crowns with and without a tin-plated, bonded platinum foil internally were compared. Visual analysis showed that (1) in the metal ceramic group, the crowns with the Rexillium III substructure were scored as more often having a lower significant Value, and (2) in the aluminous porcelain jacket group the crowns with the tin-plated, bonded platinum substructures were scored as more often having a lower significant Value.