title: Sintering behavior and mechanical properties of zirconia compacts fabricated by uniaxial press forming.
abstract: OBJECTIVE
  The purpose of this study was to compare the linear sintering behavior of presintered zirconia blocks of various densities. The mechanical properties of the resulting sintered zirconia blocks were then analyzed.
  
  
  METHODS
  Three experimental groups of dental zirconia blocks, with a different presintering density each, were designed in the present study. Kavo Everest® ZS blanks (Kavo, Biberach, Germany) were used as a control group. The experimental group blocks were fabricated from commercial yttria-stabilized tetragonal zirconia powder (KZ-3YF (SD) Type A, KCM. Corporation, Nagoya, Japan). The biaxial flexural strengths, microhardnesses, and microstructures of the sintered blocks were then investigated. The linear sintering shrinkages of blocks were calculated and compared.
  
  
  RESULTS
  Despite their different presintered densities, the sintered blocks of the control and experimental groups showed similar mechanical properties. However, the sintered block had different linear sintering shrinkage rate depending on the density of the presintered block. As the density of the presintered block increased, the linear sintering shrinkage decreased. In the experimental blocks, the three sectioned pieces of each block showed the different linear shrinkage depending on the area. The tops of the experimental blocks showed the lowest linear sintering shrinkage, whereas the bottoms of the experimental blocks showed the highest linear sintering shrinkage.
  
  
  CONCLUSIONS
  Within the limitations of this study, the density difference of the presintered zirconia block did not affect the mechanical properties of the sintered zirconia block, but affected the linear sintering shrinkage of the zirconia block.
authors.affiliation: BK21 project, School of Dentistry, Chonnam National University, Gwangju, Korea.
authors.forename: Gye-Jeong
authors.initials: GJ
authors.lastname: Oh
authors.forename: Kwi-Dug
authors.initials: KD
authors.lastname: Yun
authors.forename: Kwang-Min
authors.initials: KM
authors.lastname: Lee
authors.forename: Hyun-Pil
authors.initials: HP
authors.lastname: Lim
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Park