title: Effect of test environment and microstructure on the flexural strength of dental porcelains.
abstract: OBJECTIVE
  The objective of this study was to verify the influence of test environment on the flexural strength of dental porcelains with distinct microstructures.
  
  
  METHODS
  Disk-shaped specimens from three dental porcelains with distinct leucite content (VM: zero; CE: 12; NS: 22 vol%) were manufactured and tested for biaxial flexural strength in air and immersed in artificial saliva. The results were analyzed by means of two-way ANOVA and Tukey's test (α= 0.05).
  
  
  RESULTS
  The flexural strength (MPa) obtained for ambient air and artificial saliva environments, respectively, were: 110.0 ± 16.0 and 81.5 ± 10.8 for VM; 51.9 ± 4.0 and 42.0 ± 4.7 for CE; 72.0 ± 11.5 and 63.6 ± 5.8 for NS. A numerical decrease in the mean flexural strength was observed for all groups when specimens were tested under artificial saliva; however, the difference was only statistically significant for VM.
  
  
  CONCLUSIONS
  The results indicate that the effect of water immersion on the flexural strength of dental porcelains varies according to their leucite content, as only the material without leucite in its microstructure (VM) showed significant strength degradation when tested under water.
authors.affiliation: Department of Dental Materials, University of São Paulo, Brazil.
authors.forename: Vinicius
authors.initials: V
authors.lastname: Rosa
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.forename: Carlos Felipe Sarmento
authors.initials: CF
authors.lastname: Pereira
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Pinto
authors.forename: Humberto N
authors.initials: HN
authors.lastname: Yoshimura
mesh_terms: D000538:Aluminum Silicates; D003460:Crystallization; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D008422:Materials Testing / Q000379:methods*; D018583:Pliability; D012464:Saliva, Artificial; D013718:Tensile Strength; D014732:Vibration; D014867:Water
chemical_list: D000538:Aluminum Silicates; D012464:Saliva, Artificial; D014867:Water; D003776:Dental Porcelain; C078519:leucite