title: Influence of a bonding agent on the bond strength between a dental Co-Cr alloy and nine different veneering porcelains.
abstract: Adequate bonding between dental veneering porcelains and non-precious metal alloys is a main factor for the long-term functionality of porcelain fused to metal restorations. Although a huge number of veneering porcelains are on the market, only few studies have reported about the role of bonding agents for the bond strength at their respective interface to cobalt-chromium (Co-Cr). The aim of this study was to compare the influence of a metal-ceramic bonding agent for Co-Cr alloys on the bond strength of metal-ceramic systems. The bond strength test was done according to ISO 9693 with additional detection of the first acoustic crack initiated signal while testing. The bonding agent had only minor effects on the bond strength of the different Co-Cr/ceramic systems. Only three of the nine studied systems showed statistically significant differences (p<0.05) upon applying the bonding agent. Scanning electron microscopy (SEM) showed cracks predominantly caused by adhesive failure. Based on this study, Co-Cr alloys veneered with porcelains with and without a bonding agent exceeded the minimum bond strength of 25 MPa required according to ISO 9693. However, if bond strength values based on acoustic signals were calculated, values below the threshold of 25 MPa could be observed. Such findings are important for failures caused by the occurrence of early cracks.
authors.forename: Hassan
authors.initials: H
authors.lastname: Al Bakkar
authors.forename: Sebastian
authors.initials: S
authors.lastname: Spintzyk
authors.forename: Christine
authors.initials: C
authors.lastname: Schille
authors.forename: Ernst
authors.initials: E
authors.lastname: Schweizer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Geis-Gerstorfer
authors.forename: Frank
authors.initials: F
authors.lastname: Rupp
mesh_terms: D002858:Chromium Alloys; D003776:Dental Porcelain / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties
chemical_list: D002858:Chromium Alloys; D003776:Dental Porcelain