title: Clinical study of the color stability of veneering ceramics for zirconia frameworks.
abstract: OBJECTIVE
  The purpose of this study was to compare 3 veneering ceramics for zirconia frameworks regarding color stability and predictability of the esthetic result.
  
  
  METHODS
  Six patients with 1 maxillary central incisor to be restored were enrolled in the study. The contralateral incisor had to be nonrestored and vital to serve as a reference tooth. For each patient, 4 single crowns with zirconia frameworks were fabricated. Three veneering ceramics were assessed and masked to eliminate bias. Choice of the veneering ceramics was done at random. The veneering was performed by 4 dental technicians. Three veneering ceramics were compared: ceramic A (Initial, GC), ceramic B (Triceram, Esprident), and ceramic C (Cercon Ceram S, DeguDent). The color of the crowns and reference teeth was captured using spectrophotometric analysis (SpectroShade, MHT), and the color difference (deltaE) was calculated (objective method). In addition, the crowns and reference teeth were compared subjectively by 11 observers blind to the ceramic used for veneering. Statistical analysis was performed with analysis of variance (ANOVA).
  
  
  RESULTS
  Regardless of the veneering ceramic used, all crowns showed a high color deviation from the reference teeth when applying the objective analysis (deltaE(A) 6.8 +/- 2.5, deltaE(B) 5.6 +/- 1.2, deltaE(C) 5.7 +/- 2.1). In addition, no significant differences were found between the deltaE of crowns and teeth for the 3 ceramics. In the framework-supported area, ceramic B showed a significantly lower difference in value (deltaL) compared to the reference teeth than the other 2 ceramics (deltaL(A) 4.9 +/- 2.3, deltaL(B) 1.1 +/- 2.1, deltaL(C) 4.1 +/- 1.5; P < .01 ANOVA). When performing the subjective analysis, ceramic B was chosen as the best match by a majority of observers (> 60%) in 4 of 6 patients.
  
  
  CONCLUSIONS
  All 3 ceramics met the esthetic demands only to a limited extent. Ceramic B allowed for the most predictable result in terms of color stability.
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Dental Materials, School of Dentistry, University of Zürich, Plattenstr 11, 8032 Zürich, Switzerland. irena.sailer@zzmk.unizh.ch
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
authors.forename: Claudia
authors.initials: C
authors.lastname: Holderegger
authors.forename: Ronald Ernst
authors.initials: RE
authors.lastname: Jung
authors.forename: Ana
authors.initials: A
authors.lastname: Suter
authors.forename: Bertrand
authors.initials: B
authors.lastname: Thiévent
authors.forename: Nicola
authors.initials: N
authors.lastname: Pietrobon
authors.forename: Walter
authors.initials: W
authors.lastname: Gebhard-Achilles
authors.forename: Christoph Hans Franz
authors.initials: CH
authors.lastname: Hämmerle
mesh_terms: D000704:Analysis of Variance; D003116:Color; D003124:Colorimetry; D003442:Crowns; D003776:Dental Porcelain; D003801:Dental Veneers; D006801:Humans; D007180:Incisor; D016876:Metal Ceramic Alloys; D017797:Prosthesis Coloring; D013674:Technology, Dental; D015040:Zirconium
chemical_list: D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide