title: Translucency of zirconia-based pressable ceramics with different core and veneer thicknesses.
abstract: BACKGROUND
  Little information is available on the translucency of zirconia-based pressable ceramic restorations with a pressed ceramic veneer and zirconia core in various thickness combinations.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to assess the translucency of 3 types of zirconia-based pressable ceramics for different core-veneer thickness combinations.
  
  
  METHODS
  A bilayered ceramic specimen was prepared with a pressable ceramic (IPS e.max Zirpress, Initial IQ, Rosetta UltraPress) veneer over a zirconia core (Zenostar Zr). Three groups of specimens (n=7) were formed with the following core+veneer thicknesses: 1 +0.5 mm, 0.7 +0.8 mm, and 0.5 +1 mm. To obtain consistent thickness and high translucency, all specimens were subjected to surface grinding with a grinding machine. To eliminate the effect of differences in roughness on the translucency, the surface roughness of the ground specimens was measured with a scanning profiler, and the consistency of these measured values was verified through statistical analysis. The luminous transmittance of the specimens was measured with a spectrophotometer. The effects of the pressable ceramic type and core-veneer thickness combination on transmittance were assessed using a 2-way ANOVA (α=.05).
  
  
  RESULTS
  The consistency of the surface roughness among the tested specimens was confirmed using a 1-way ANOVA and the Tukey HSD post hoc test (P<.05). The luminous transmittance exhibited a statistically significant dependence on both the type of pressable ceramic and the core-veneer thickness combination (P<.05).
  
  
  CONCLUSIONS
  The type of pressable ceramic and core-veneer thickness combination affected the translucency of the restoration.
authors.affiliation: Doctoral student, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Il-Do
authors.initials: ID
authors.lastname: Jeong
authors.affiliation: Doctoral student, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Bae
authors.affiliation: Graduate student, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Dong-Yeon
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Ji-Hwan
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Professor, Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, Seoul, Republic of Korea. Electronic address: kuc2842@korea.ac.kr.
authors.forename: Woong-Chul
authors.initials: WC
authors.lastname: Kim
mesh_terms: D002516:Ceramics / Q000737:chemistry / Q000627:therapeutic use*; D003801:Dental Veneers; D006801:Humans; D008027:Light; D011176:Post and Core Technique; D013053:Spectrophotometry; D015040:Zirconium / Q000737:chemistry / Q000627:therapeutic use*
chemical_list: D015040:Zirconium; C028541:zirconium oxide