title: Color variation induced by abutments in the superior anterior maxilla: anin vitrostudy in the pig gingiva.
abstract: OBJECTIVE
  The aim of this work is to evaluate different types of materials used for making implant abutments, by means of anin vitrostudy and a review of the literature, in order to identify the indications for a better choice of an implant-supported restoration in the anterior section.
  
  
  METHODS
  5 implant abutments were tested in a random order in the superior anterior maxilla of pig gingiva (n = 8): titanium dioxide (Nobel Biocare); zirconium dioxide, Standard BO shade (Nobel Biocare, Kloten, Switzerland); zirconium dioxide, Light BI shade (Nobel Biocare); zirconium dioxide, Intense A 3.5 shade (Nobel Biocare); and aluminium oxide. Each abutment was tested for 2 mm and 3 mm thickness. To determine color variation, VITA Easyshade Advance spectrophotometer (Vita Zahnfabrik, Bad Sackingen, Germany) was used.
  
  
  RESULTS
  Results showed that the color variation induced by the abutment would be affected by the abutment material and gingival thickness, when the gingival thickness is 2 mm. All materials except zirconium dioxide (Standard shade) caused a visible change of color. Then, as the thickness of the gingiva increased to 3 mm, the color variation was attenuated in a significant manner and became invisible for all types of abutments, except those made of aluminium oxide.
  
  
  CONCLUSIONS
  Zirconium dioxide is the material causing the lowest color variation at 2 mm and at 3 mm, whereas aluminium oxide causes the highest color variation no matter the thickness.
authors.affiliation: Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Ramin
authors.initials: R
authors.lastname: Atash
authors.affiliation: Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Mohamed-Reda
authors.identifier: 0000-0002-0446-5660
authors.initials: MR
authors.lastname: Boularbah
authors.affiliation: Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.; Laboratory of Physiology and Pharmaceutics, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Cetik
authors.identifier: 0000-0001-8338-3921
authors.initials: C
authors.lastname: Sibel
keywords: Abutment; Anterior restoration; Gingiva; Zirconium oxide