title: Biaxial flexural strength of CAD/CAM ceramics.
abstract: OBJECTIVE
  Aim of the study was to evaluate the biaxial flexural strength of ceramics processed using the Cerec inLab system. The hypothesis was that the flexural strength would be influenced by the type of ceramic.
  
  
  METHODS
  Ten samples (ISO 6872) of each ceramic (N.=50/n.=10) were made using Cerec inLab (software Cerec 3D) (Ø:15 mm, thickness: 1.2 mm). Three silica-based ceramics (Vita Mark II [VM], ProCad [PC] and e-max CAD ECAD]) and two yttria-stabilized tetragonal-zirconia-polycrystalline ceramics (Y-TZP) (e-max ZirCad [ZrCAD] and Vita In-Ceram 2000 YZ Cubes [VYZ]) were tested. The samples were finished with wet silicone carbide papers up to 1 200-grit and polished in a polishing machine with diamond paste (3 µm). The samples were then submitted to biaxial flexural strength testing in a universal testing machine (EMIC), 1 mm/min. The data (MPa) were analyzed using the Kruskal-Wallis and Dunn (5%) tests. Scanning electronic microscopy (SEM) was performed on a representative sample from each group.
  
  
  RESULTS
  The values (median, mean±sd) obtained for the experimental groups were: VM (101.7, 102.1±13.65 MPa), PC (165.2, 160±34.7 MPa), ECAD (437.2, 416.1±50.1 MPa), ZrCAD (804.2, 800.8±64.47 MPa) and VYZ (792.7, 807±100.7 MPa). The type of ceramic influenced the flexural strength values (P=0.0001). The ceramics ECADa, e-max ZrCADa and VYZa presented similar flexural strength values which were significantly higher than the other groups (PCb and VM IIb), which were similar statistically between them (Dunn's test). The hypothesis was accepted.
  
  
  CONCLUSIONS
  The polycrystalline ceramics (Y-TZP) should be material chosen for make FPDs because of their higher flexural strength values.
authors.affiliation: São Paulo State University, São José dos Campos, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Buso
authors.forename: O B
authors.initials: OB
authors.lastname: Oliveira-Júnior
authors.forename: F
authors.initials: F
authors.lastname: Hiroshi Fujiy
authors.forename: G H
authors.initials: GH
authors.lastname: Leão Lombardo
authors.forename: H
authors.initials: H
authors.lastname: Ramalho Sarmento
authors.forename: F
authors.initials: F
authors.lastname: Campos
authors.forename: R O
authors.initials: RO
authors.lastname: Assunção Souza
mesh_terms: D002516:Ceramics; D003799:Dental Stress Analysis; D008422:Materials Testing; D013499:Surface Properties