title: Fracture Toughness of Veneering Ceramics for Fused to Metal (PFM) and Zirconia Dental Restorative Materials.
abstract: Veneering ceramics designed to be used with modern zirconia framework restorations have been reported to fracture occasionally in vivo. The fracture toughness of such veneering ceramics was measured and compared to that of conventional feldspathic porcelain veneering ceramics for metal framework restorations. The fracture toughness of the leucite free veneer was measured to be 0.73 MPa m ± 0.02 MPa m, which is less than that for the porcelain fused to metal (PFM) veneering ceramic: 1.10 MPa ± 0.2 MPa. (Uncertainties are one standard deviation unless otherwise noted.) The surface crack in flexure (SCF) method was suitable for both materials, but precrack identification was difficult for the leucite containing feldspathic porcelain PFM veneer.
authors.affiliation: American Dental Association Foundation, Paffenberger Research Center, National Institute of Standards and Technology, Gaithersburg, MD.
authors.forename: Janet B
authors.initials: JB
authors.lastname: Quinn
authors.forename: George D
authors.initials: GD
authors.lastname: Quinn
authors.forename: Veeraraghaven
authors.initials: V
authors.lastname: Sundar