Variations of L*a*b* Values among Vitapan^® Classical Shade Guides

Abstract

The differences observed between shade guides are larger than the variations induced by the experimental method. The difference in E values for the shades C1 and C2 is 2.19; hence the observed E(r) of 3.05 between shade tabs of the same shade (C1) is larger than the changes in color between shades. This large a variation in what are claimed as identical shade tabs is deemed of clinical importance, and therefore, the shade guides should not be considered interchangeable.

Could digital imaging be an alternative for digital colorimeters?

“…The use of such softwares on PCs has Fig. 3 a-b L* versus C*ab for representative A1, A2, A3 and A3,5 shade tabs obtained at a 2,700 K and 2700-6500 K colour temperature using the digital imaging method b 6,500 K colour temperature using the digital imaging method and the colorimeter controversial outcome [18][19][20]. In those studies, the studied material was the tooth brightness and translucency after vital bleaching using L* and RGB values.…”

Factors Affecting Color Reproducibility of Resin-veneered Prostheses

“…For example, Yilmaz et al reported that the replication of high-value shades was observed to be reliable [9], and Lagouvardos et al indicated that some shades produced a more reliable and valid match than others regardless of the brightness [14]. Other factors such as the region of the crown [15][16][17] and the type of shade guide used to select the color in the dental office and in the dental laboratory [2,13,14,[18][19][20] have also been reported to be related.…”

The Effect of Chemical Disinfectants on the Color of a Porcelain Shade Guide

“…(6)(7)(8)(9) There have also been reported discrepancies related within similar shade tab from the same manufacturer, and also between different shade guide systems. (10)(11) Therefore, absolute care must be followed in performing shade matching including handling and sterilization of the shade guide itself. Manufacturer's recommendation for sterilization of conventional shade guide includes chemical disinfectants with solutions that doesn't include component of phenol or methyl ethyl ketone.…”