title: Evaluation of an optimized shade guide made from porcelain powder mixtures.
abstract: BACKGROUND
  Color errors associated with current shade guides and problems with color selection and duplication are still challenging for restorative dentists.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate an optimized shade guide for visual shade duplication.
  
  
  METHODS
  Color distributions (L*, a*, and b*) of the maxillary left central incisors of 236 participants, whose ages ranged from 20 to 60, were measured with a spectrophotometer. Based on this color map, an optimized shade guide was designed with 14 shade tabs evenly distributed within the given color range of the natural incisors. The shade tabs were fabricated with porcelain powder mixtures and conventional laboratory procedures. A comparison of shade duplication by using the optimized and Vitapan Classical shade guides was conducted. Thirty Chinese participants were involved, and the colors of the left maxillary incisors were selected by using 2 shade guides. Metal ceramic crowns were fabricated according to the results of the shade selection. The colors of the shade tabs, natural teeth, and the ceramic crowns were measured with a spectrophotometer. The color differences among the natural teeth, the shade tabs, and the corresponding metal ceramic crowns were calculated and analyzed (α=.017).
  
  
  RESULTS
  Significant differences were found in both phases of shade determination and shade duplication (P<.017). The total number of color errors with the optimized shade guide was 3.5, which was significantly less than that of Vitapan, 5.1 (P<.001).
  
  
  CONCLUSIONS
  The optimized shade guide system improved performance not only in the color selection phase but also in the color of the fabricated crowns.
authors.affiliation: Doctoral student, State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Doctoral student, State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: Jiaqiang
authors.initials: J
authors.lastname: Wei
authors.affiliation: Associate Professor, State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: Chief and Professor, State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China. Electronic address: wang.yn@whu.edu.cn.
authors.forename: Yining
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D003116:Color; D003442:Crowns; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008875:Middle Aged; D011208:Powders / Q000737:chemistry; D017797:Prosthesis Coloring / Q000295:instrumentation*; D013053:Spectrophotometry / Q000295:instrumentation; D055815:Young Adult
chemical_list: D016876:Metal Ceramic Alloys; D011208:Powders; D003776:Dental Porcelain