title: Optical properties of current ceramics systems for laminate veneers.
abstract: OBJECTIVE
  Full-ceramic systems can be produced by different techniques (layering, heatpressing, CAD/CAM) and have various compositions with different crystalline contents that may affect the optical properties of laminate restorations.
  
  
  METHODS
  A total of 60 specimens were prepared from e.max Press, e.max CAD, Empress Esthetic, e.max Ceram, Inline, and ZirPress systems (A1 shade; diameter 10mm; thickness 0.5 ± 0.05mm). The L*, a*, and b* values, chroma and translucency (TP) of each system were recorded before and after ageing. The statistical analyses were performed by ANOVA, Tukey's tests and the paired sample t-test (p<0.05).
  
  
  RESULTS
  The L* value of the shade guide was significantly different from those of the full-ceramic systems; however, there were no significant differences between the a* values of Ceram, Esthetic, Inline and Zirpress. There were significant differences between the b* values of the shade guide compared with the full-ceramics except for e.max Press. The L* values decreased, and the a* and b* values increased after the ageing process for all groups. There were no significant differences between the ΔE values of the ceramic systems (p>0.05). The TP values decreased, and the chroma value increased significantly after the ageing process (p>0.05). The chroma of the shade guide was found to be the highest.
  
  
  CONCLUSIONS
  None of the full-ceramic systems was able to match the color of the shade guide. The chemical structures of the ceramic systems were more effective for determining the optical parameters than the fabrication techniques. Ageing caused full-ceramics to become more opaque, darker, reddish and yellowish.
authors.affiliation: DDS Izmir Katip Celebi University, Faculty of Dentistry, Department of Prosthodontics, Izmir, Turkey. bbagis@yahoo.com
authors.forename: Bora
authors.initials: B
authors.lastname: Bagis
authors.forename: Sedanur
authors.initials: S
authors.lastname: Turgut
mesh_terms: D000465:Algorithms; D000538:Aluminum Silicates / Q000737:chemistry; D001031:Apatites / Q000737:chemistry; D003116:Color; D003124:Colorimetry; D003461:Crystallography; D003776:Dental Porcelain / Q000737:chemistry*; D003801:Dental Veneers; D006813:Humidity; D008027:Light; D049329:Nanostructures / Q000737:chemistry; D017797:Prosthesis Coloring / Q000295:instrumentation; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D001031:Apatites; C520133:IPS e.max CAD LT; C508050:IPS e.max Press; C075815:IPS-Empress ceramic; C493120:lithia disilicate; D014867:Water; D003776:Dental Porcelain; C078519:leucite; C025105:fluorapatite