Rade D. Paravina, DDS, MS
Ljubisav N. Igic, DDS, PhD
Faculty of Medicine, University of Nis
Nis, Yugoslavia

Colorimetric analysis of certain commercial shade guides was done. The aim of the study was to examine color differences between average tooth color and color in gingival, middle and incizal third and the color differences between these thirds of dental shade guide samples. Previously prepared samples from commercial shade guide were examined. Samples were recorded using color scanner. Digital image analysis was done using computer. Shade determination was done 9 times in four measured areas for each of the 63 samples. The results were presented in the CIELAB color system. Total color differences between average tooth color and color in gingival, middle and incizal third were 3.43, 0.96 and 3.29 DE units, respectively. Total color differences between gingival and middle, gingival and incizal and middle and incizal third were 3.94, 6.33 and 3.53 DE units, respectively. Differences in color coordinate values in gingival, middle and incizal third explain the origin of total color differences among them. Samples were the darkest, the most saturated and with the lowest hue values in the gingival third and vice versa in the incizal third. Small color difference between the middle third and average tooth's color indicates that the middle third could represent tooth's color. (Acta Stom Naissi 1999;16:25-29)

Reprint requests to: RADE D. PARAVINA, DEPARTMENT OF PROSTHODONTICS, FACULTY OF MEDICINE, UNIVERSITY OF NIS, 52 BRACE TASKOVIC STR, 18000 NIS, YUGOSLAVIA, FAX: +381 18 33 38 39; E-MAIL: paravina@junis.ni.ac.yu