title: Factors involved in the spectrophotometric measurement of soft tissue: A clinical study of interrater and intrarater reliability.
abstract: BACKGROUND
  The reliability of spectrophotometric measurements of gingival color has not been tested.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the repeatability and reproducibility of gingival color measurements with a digital spectrophotometer. Measurement error was estimated by determining the interrater agreement and by repeating measurements in different illumination environments with and without contact of the device with the gingiva.
  
  
  METHODS
  Two trained examiners measured the gingival shade around 30 central incisors with a spectrophotometer with and without external illumination and with and without contact of the device with the gingiva. Color data obtained (CIELab color coordinates; L*, c*, h*, a*, b*) were analyzed with the intraclass correlation coefficient (ICC) and the Student t test for paired samples.
  
  
  RESULTS
  Mean L*, c*, a*, and b* values differed significantly between measurements made with and without contact of the device with the tissue, but no difference was found in h* values. An ICC of >0.9 was obtained for interrater and intrarater agreements in all cases. Shade measurements did not differ between the presence and absence of stable ambient light.
  
  
  CONCLUSIONS
  The repeatability and reproducibility of soft tissue shade measurements were almost perfect (ICC >0.9) under the examination conditions tested. The measurements were affected by pressure but not by ambient light.
authors: Graduate student, Department of Periodontology, School of Dentistry, Complutense University of Madrid, Madrid, Spain. Electronic address: letisala@hotmail.com.
authors: Leticia
authors: L
authors: Sala
authors: Professor, Department of Periodontology, School of Dentistry, Complutense University of Madrid, Madrid, Spain.
authors: Ana
authors: A
authors: Carrillo-de-Albornoz
authors: Associate Professor, Department of Orthodontics, School of Dentistry, Complutense University of Madrid, Madrid, Spain.
authors: Conchita
authors: C
authors: Martín
authors: Chief Professor, Department of Periodontology, School of Dentistry, Complutense University of Madrid, Madrid, Spain.
authors: Antonio
authors: A
authors: Bascones-Martínez
mesh_terms: D000328:Adult; D003116:Color; D005260:Female; D005881:Gingiva / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000706:statistics & numerical data; D007633:Keratins; D008029:Lighting / Q000295:instrumentation; D008297:Male; D015588:Observer Variation; D011312:Pressure; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000295:instrumentation / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D007633:Keratins