title: Effect of Thickness, Processing Technique and Cooling Rate Protocol on the μTBS of a Bilayer Ceramic System.
abstract: OBJECTIVE
  To evaluate the influence of different processing techniques, ceramic thicknesses, and cooling rate protocols on the μTBS of a veneering ceramic to zirconia (Y-TZP).
  
  
  METHODS
  Eighty Y-TZP ceramic blocks (VITA In-Ceram 2000) with dimensions of 10 x 7 x 5 mm were obtained. The blocks were sintered in a special furnace at 1500° for 2 h, wet ground, and divided into 8 groups according to the factors "processing technique" (P: pressed/veneering ceramic PM9; or V: layered/ veneering ceramic VM9), "thickness" (2 mm and 4 mm), and "cooling protocol" (S: slow [10°C/s]; F: fast [50°C/s]). The Y-TZP/veneering ceramic blocks were sectioned to produce non-trimmed bar specimens (bonded area: 1±0.1 mm2), which were submitted to 1200 thermal cycles (5°C and 55°C, 30-s dwell time) and stored for 1 week in distilled water (37°C) before microtensile testing in a universal test machine (EMIC, 1 mm/min). The data in MPa were analyzed statistically using three-way ANOVA and Tukey's test.
  
  
  RESULTS
  ANOVA revealed that only the factor processing technique was significant (p=0.015), unlike the factors thickness (p=0.111) and cooling protocol (p=0.202). The majority of the failures were classified as adhesive.
  
  
  CONCLUSIONS
  Layered application of a thin veneering ceramic using a fast cooling rate resulted in improved bonding between veneering ceramic and zirconia.
authors.forename: Fernanda
authors.initials: F
authors.lastname: de Cássia Papaiz Gonçalves
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Bottino
authors.forename: Renata Marinho
authors.initials: RM
authors.lastname: Marques de Melo
authors.forename: Rodrigo Othavio
authors.initials: RO
authors.lastname: Assunção Souza
mesh_terms: D000268:Adhesiveness; D000538:Aluminum Silicates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017680:Potassium Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; C499362:yttria stabilized tetragonal zirconia; D014867:Water; C016447:feldspar; D015019:Yttrium; D015040:Zirconium