title: The Esthetic Effect of Veneered Zirconia Abutments for Single-Tooth Implant Reconstructions: A Randomized Controlled Clinical Trial.
abstract: OBJECTIVE
  The purposes of this study were to test whether or not veneering of the submucosal part of zirconia abutments can positively influence the esthetic outcome compared with nonveneered zirconia abutments; to evaluate the influence of the mucosal thickness on the esthetic outcomes of the veneered and nonveneered abutments; and to evaluate the thickness of the peri-implant mucosa compared with the thickness of the gingiva of contralateral tooth sites.
  
  
  METHODS
  Forty-four single-tooth implants in 44 patients were randomly restored with either cemented (CR) or screw-retained (SR) reconstructions based on white zirconia abutments (CR-W, SR-W) or pink-veneered zirconia abutments (CR-P, SR-P). Esthetic outcome measurements were performed based on a spectrophotometric evaluation of the peri-implant mucosal color. In addition, the thickness of the mucosa was measured. A two-way analysis of variance was conducted to test the effect of veneering (pink vs white) and mucosa thickness (<2 mm vs ≥2 mm) on the calculated color difference ΔE for pooled data of CR and SR reconstructions (p < .05).
  
  
  RESULTS
  Analyses grouping the sites according to veneering of the abutments and mucosal thickness demonstrated less discoloration for sites with a veneered abutment irrespective of the mucosal thickness: ΔE 4.50 ± 1.93 (<2 mm) and ΔE 6.88 ± 2.45 (≥2 mm); CR-P, SR-P) compared with sites without veneering ΔE 9.72 ± 3.82 (<2 mm; CR-W, SR-W) and ΔE 8.31 ± 2.98 (≥2 mm). The differences between veneered and nonveneered abutments were significant (p = .032).
  
  
  CONCLUSIONS
  Veneering of zirconia abutments with pink veneering ceramic positively influenced the peri-implant mucosal color.
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Thoma
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Francine
authors.initials: F
authors.lastname: Brandenberg
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, Clinic of Dental Medicine, University of Geneva, Zürich, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Fehmer
authors.affiliation: Center for Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Knechtle
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Christoph Hf
authors.initials: CH
authors.lastname: Hämmerle
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, Clinic of Dental Medicine, University of Geneva, Zürich, Switzerland.
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
mesh_terms: D000044:Dental Abutments; D003801:Dental Veneers; D004955:Esthetics, Dental; D006801:Humans; D015040:Zirconium
chemical_list: D015040:Zirconium
keywords: ceramic abutments; crowns; dental abutments; dental implants; zirconia