Effect of extrinsic pigmentation and surface treatments on biaxial flexure strength after cyclic loading of a translucent ZrO2 ceramic

Breno Fortes Bittar, Jean Soares Miranda, Arthur Chaves Simões, Nathália de Carvalho Ramos, João P.B. Machado, Yu Zhang, Rodrigo Othávio Assunção Souza, Fabíola Pessôa Pereira Leite

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To evaluate the influence of extrinsic pigmentation on the biaxial flexural strength and surface topographic of translucent Y-TZP (InCoris TZI – Sirona – USA) subjected to several surface treatments. Methods: Sintered zirconia discs-shaped specimens (n = 120) (ø:12 mm; thickness:1.2 mm; ISO 6872) were prepared and divided (n = 15) according to various factors: “extrinsic pigmentation” (n: without; p: with) and “surface treatments” (C: control — as sintered; A: abraded with silica-coated alumina particles (30 μm); G: glazed with a thin film of low-fusing porcelain glaze; GH: glazed and etched with 10% hydrofluoridric acid for 60 s. Mechanical cycling (1.2 × 106 cycles, 200 N, 3.8 Hz) and flexural strength test (1 mm/min — 1000 kg cell) were performed. Two-way ANOVA and Tukey's were used for statistical test (α = 0.05). Weibull analysis was used to evaluate the strength reliability. Samples were analyzed via (1) an optical profilometer to determine the surface roughness (Ra); (2) an X-ray diffraction (XRD) to evaluate phase transformations; and (3) a SEM equipped with an energy dispersive X-ray spectroscopy (EDX) to elucidate morphological properties and chemical compositions. Results: Regardless of the surface treatment (p = 0.5459) (Cn: 560.16 MPa; Gn: 573.36 MPa; An: 643.51 MPa; GHn: 542.94 MPa; Cp: 628.04 MPa; Gp: 641.90 MPa; Ap: 554.47 MPa; GHp :602.84 MPa) and extrinsic pigmentation (p = 0.1280) there was no difference in the flexural strength among the experimental groups. According to the XRD analysis, phase transformations occurred in the An group (t → m) and in Ap group (t → c). Surface roughness was affected by surface treatments (An — p = 0.001) and extrinsic pigmentation (Gp — p = 0.001). Significance: The biaxial flexural strength of the tested samples was not affected neither by surface treatments nor by pigmentation, although it can cause phase transformation and promote surface roughness.

Original languageEnglish (US)
Pages (from-to)1644-1653
Number of pages10
JournalDental Materials
Volume35
Issue number11
DOIs
StatePublished - Nov 2019

Keywords

  • Biaxial flexural strength
  • Phase transformation
  • Surface characterization
  • Zirconia surface treatment

ASJC Scopus subject areas

  • Materials Science(all)
  • Dentistry(all)
  • Mechanics of Materials

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