title: Interfacial characterization of ceramic core materials with veneering porcelain for all-ceramic bi-layered restorative systems.
abstract: OBJECTIVE
  The aim of the study was to characterize the elemental distribution at the interface between all-ceramic core and veneering porcelain materials.
  
  
  METHODS
  Three groups of all-ceramic cores were selected: A) Glass-ceramics (Cergo, IPS Empress, IPS Empress 2, e-max Press, Finesse); B) Glass-infiltrated ceramics (Celay Alumina, Celay Zirconia) and C) Densely sintered ceramics (Cercon, Procera Alumina, ZirCAD, Noritake Zirconia). The cores were combined with compatible veneering porcelains and three flat square test specimens were produced for each system. The core-veneer interfaces were examined by scanning electron microscopy and energy dispersive x-ray microanalysis.
  
  
  RESULTS
  The glass-ceramic systems showed interfacial zones reach in Si and O, with the presence of K, Ca, Al in core and Ca, Ce, Na, Mg or Al in veneer material, depending on the system tested. IPS Empress and IPS Empress 2 demonstrated distinct transitional phases at the core-veneer interface. In the glassinfiltrated systems, intermixing of core (Ce, La) with veneer (Na, Si) elements occurred, whereas an abrupt drop of the core-veneer elemental concentration was documented at the interfaces of all densely sintered ceramics.
  
  
  CONCLUSIONS
  The results of the study provided no evidence of elemental interdiffusion at the core-veneer interfaces in densely sintered ceramics, which implies lack of primary chemical bonding. For the glass-containing systems (glassceramics and glass-infiltrated ceramics) interdiffusion of the glass-phase seems to play a critical role in establishing a primary bonding condition between ceramic core and veneering porcelain.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tagmatarchis
authors.forename: Aris-Petros
authors.initials: AP
authors.lastname: Tripodakis
authors.forename: Gerasimos
authors.initials: G
authors.lastname: Filippatos
authors.forename: Spiros
authors.initials: S
authors.lastname: Zinelis
authors.forename: George
authors.initials: G
authors.lastname: Eliades
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D003801:Dental Veneers; D004577:Electron Probe Microanalysis; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties
chemical_list: D003764:Dental Materials; D003776:Dental Porcelain; C023506:Glass ceramics