title: [Chromatic study of all-ceramic restorations--influence of abutment tooth color on color tone of copings].
abstract: OBJECTIVE
  Recently, the use of all-ceramic crowns has spread widely in clinical applications to meet the demand for both functional and esthetically-pleasing restorations. In making all-ceramic crowns, it is necessary to reproduce the shape and color near to those of the natural teeth. However, the color shades of abutments might influence the color of the copings which are made of material with high transparency. This study examined the influence of the color shades of the abutments on the final color of copings for three kinds of all-ceramic core materials: Empress, Empress 2 (IVOCLAR VIVADENT), and Procera AllCeram (Nobel Biocare).
  
  
  METHODS
  Copings with 0.5 mm in thickness were fabricated by using Empress (TC1), Empress 2 (100), and Procera AllCeram (white) core materials for an upper-right central incisor. Abutments were made by using six kinds of die materials of the Empress system (ST1, ST2, ST3, ST5, ST8, ST9), gold-silver-palladium alloy, gold alloy, and experimental black body. Copings were inserted in each abutment and the final color of the central part of the buccal surface was measured using a spectrophotometer according to the L*a*b* color system.
  
  
  RESULTS
  Regardless of the color shades of the abutments, the chroma values of the copings rose in the order of Empress, Empress 2, and Procera, and the values of lightness rose in the order of Empress, Procera, and Empress 2. When the final color of each coping measured under the wet and dry conditions were compared, the difference in chroma was great.
  
  
  CONCLUSIONS
  Within the limitations of this study, the results suggest that the influence of the color shades of the abutments on the final color of the three kinds of copings is small in the order of Empress, Procera, and Empress 2. In clinical and dental laboratory operations, it is hoped to observe and measure the color of copings and restorations under the wet condition.
authors.affiliation: Department of Prosthodontics, Division of Oral Functional Science and Rehabilitation, Asahi University School of Dentistry. utako@dent.asahi-u.ac.jp
authors.forename: Utako
authors.initials: U
authors.lastname: Hata
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamamura
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kawauchi
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Fujii
mesh_terms: D002516:Ceramics; D003116:Color; D000044:Dental Abutments; D003764:Dental Materials; D003793:Dental Restoration, Permanent / Q000379:methods*
chemical_list: D003764:Dental Materials