title: [Comparison of clinically used shade guide systems with color range of natural teeth].
abstract: OBJECTIVE
  To analyze the limitation of currently used shade guide systems comparing with color range of nature teeth.
  
  
  METHODS
  Digital pictures of shade guide systems A (VITAPAN Classic), B (VINTAGE Halo), C (3D-MASTER), and 322 central incisors were taken under the same condition as light source of D65 with the observation method of d/0 degrees. The data obtained from nature tooth color were compared with the color range of three shade guide systems mentioned above in items of L * a * b */C * H degrees.
  
  
  RESULTS
  The normal chroma value (95%) of the natural teeth were L* 61.631-73.250, a * -0.719-1.879, and b * 8.701-17.790. Natural tooth colors were different from those of the shade guide system A which color range was narrower, short of red hue, higher values, and unevenly distribution of saturation. On the other hand, the range of red hue increased in shade guide system B while its saturation was slightly high. The color range of shade guide system C was greatest among the three shade guide systems. The saturation and value of shade guide system C covered all varieties of nature teeth measured in this research, but it still lacked red hue comparing to the nature teeth.
  
  
  CONCLUSIONS
  Comparing the color range of nature teeth, the shade guide systems used in clinic have uneven hue distribution and cannot cover all colors of nature teeth. Generally, all the shade guide systems are lack of the hues which are named under the category of red tone.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Shanghai Jiao Tong University, Shanghai 200011, China
authors.forename: Qi-min
authors.initials: QM
authors.lastname: Ge
authors.forename: Fu-qiang
authors.initials: FQ
authors.lastname: Zhang
mesh_terms: D000328:Adult; D003124:Colorimetry / Q000379:methods; D017267:Dental Prosthesis Design; D005260:Female; D006801:Humans; D007180:Incisor; D008297:Male; D017797:Prosthesis Coloring; D055815:Young Adult