Title: Effect of High-Speed Sintering on the Properties of Zirconia-Oxide Materials
McKinley Soult (Presenter)
Wen Lien, USAF
Francisco Gallardo, USAF
Kraig Vandewalle, USAF
Objectives: Digital dentistry has led to the popular success of same-day single crown delivery. However, traditional fabrication of zirconia materials typically requires several hours of sintering. A new sintering furnace is available that reportedly sinters zirconia in minutes versus hours. Limited research has been published evaluating the effect of high-speed sintering on the properties of zirconia. The purpose of this study was to compare the mechanical properties and translucency of CEREC Zirconia (Dentsply/Sirona) sintered using the CEREC SpeedFire high-speed sintering furnace (Dentsply/Sirona) for 30 minutes and Programat 1600 S1 (Ivoclar Vivadent) for 4.3 hours.
Methods: Beam-shaped specimens were designed using an Omnicam (Version 4.4.4; Dentsply/Sirona) and milled from CAD/CAM blocks using a MCXL milling unit (Dentsply/Sirona), polished, and sintered using the CEREC SpeedFire furnace or the Programat 1600 S1 for the CEREC Zirconia. The properties of the zirconia were also compared to a lithium-disilicate material, IPS e.max CAD (Ivoclar Vivadent). IPS e.max CAD beams were crystallized in the CEREC SpeedFire furnace or Programat P500. Flexural strength and modulus were determined by subjecting the beams (4 x 1.3 x 18mm) to a three-point bend test in a universal testing machine (Instron). Translucency Parameter and Opalescence Parameter were calculated using a spectrophotometer (VITA Easyshade, Vident) that measured L*, a*, and b* values. A mean and standard deviation was determined per group. Data were analyzed with a two-way ANOVA/Tukey’s and unpaired t-tests (alpha=0.05).
Results: No significant differences were found for any of the properties tested between the furnaces for both of the ceramic materials (p>0.05). CEREC Zirconia had significantly greater flexural strength than IPS e.max CAD, but had significantly less Translucency Parameter and Opalescence Parameter.
Conclusions: The SpeedFire furnace was capable of sintering the zirconia beams in significantly less time than with the Programat S1 furnace with no significant change in properties.