title: Influence of implant abutment material on the color of different ceramic crown systems.
abstract: BACKGROUND
  Ceramics are widely used for anterior restorations; however, clinical color reproduction still constitutes a challenge particularly when the ceramic crowns are used on titanium implant abutments.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to investigate the effect of implant abutment material on the color of different ceramic material systems.
  
  
  METHODS
  Forty disks (11×1.5 mm, shade A2) were fabricated from medium-opacity (mo) and high-translucency (ht) lithium disilicate (IPS e.max) blocks, an aluminous ceramic (VITA In-Ceram Alumina), and a zirconia (Zirkonzahn) ceramic system. Disks were fabricated to represent 3 different implant abutments (zirconia, gold-palladium, and titanium) and dentin (composite resin, A2 shade) as background (11×2 mm). Disk-shaped composite resin specimens in A2 shade were fabricated to represent the cement layer. The color measurements of ceramic specimens were made on composite resin abutment materials using a spectrophotometer. CIELab color coordinates were recorded, and the color coordinates measured on composite resin background served as the control group. Color differences (ΔE00) between the control and test groups were calculated. The data were analyzed with 2-way analysis of variance (ANOVA) and compared with the Tukey HSD test (α=.05).
  
  
  RESULTS
  The ceramics system, abutment material, and their interaction were significant for ΔE00values (P<.001). Clinically unacceptable results (ΔE00>2.25) were observed for lithium disilicate ceramics on titanium abutments (2.46-2.50). The ΔE00values of lithium disilicate ceramics for gold-palladium and titanium abutments were significantly higher than for other groups (P<.05).
  
  
  CONCLUSIONS
  The color results (ΔE00>2.25) of an implant-supported lithium disilicate ceramic restoration may be clinically unacceptable if it is fabricated over a titanium abutment. Zirconia may be a more suitable abutment material for implant-supported ceramic restorations.
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Ordu University, Ordu, Turkey.
authors.forename: Doğu Ömür
authors.initials: DÖ
authors.lastname: Dede
authors.affiliation: Practitioner, Samsun Public Oral Health Center, Samsun, Turkey.
authors.forename: Arzu
authors.initials: A
authors.lastname: Armağanci
authors.affiliation: Professor, Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Gözlem
authors.initials: G
authors.lastname: Ceylan
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Ordu University, Ordu, Turkey.
authors.forename: Ersan
authors.initials: E
authors.lastname: Celik
authors.affiliation: Professor, Department of Biostatistics, Faculty of Medicine, Ordu University, Ordu, Turkey.
authors.forename: Soner
authors.initials: S
authors.lastname: Cankaya
authors.affiliation: Associate Professor, Division of Restorative Science and Prosthodontics, The Ohio State University, College of Dentistry, Columbus, Ohio. Electronic address: yilmaz.16@osu.edu.
authors.forename: Burak
authors.initials: B
authors.lastname: Yilmaz
mesh_terms: D002516:Ceramics; D003116:Color; D003442:Crowns; D003738:Dental Cements; D003764:Dental Materials; D003776:Dental Porcelain; D006801:Humans; D008422:Materials Testing; D015040:Zirconium
chemical_list: D003738:Dental Cements; D003764:Dental Materials; C483026:In-Ceram Alumina; D003776:Dental Porcelain; D015040:Zirconium