The Effect of Ceramic Surface Treatment and Measurement Geometry of Spectrophotometric Shade Devices on the Color of All Ceramic Systems

Objectives: To optimize the clinical outcome of ceramic restorations it is important to determine the effect of different ceramic characteristics on the final color. However there is a lack of information how color information of different shade measurement devices is affected by surface conditioning. Therefore the purpose of this study is to evaluate the effect of surface topography and color measuring geometry on the color of ceramic restorations.
Methods: Thirty all ceramic monolithic crowns (IPS e.max CAD, Ivoclar Vivadent AG, Schaan Liechtenstein) were fabricated using a CAD/CAM-System. The selected color was A2 and the crowns were divided into two groups in accordance to their translucencies (LT/HT). Three surface groups were spectrophotometrically evaluated with a spot-measurement device (VITA Easyshade compact, VITA Zahnfabrik GmbH, Bad Säckingen Germany) and an area-measurement device (DeguDent ShadePilot, DeguDent GmbH, Hanau, Germany). The color data was expressed in CIE L*a*b* system coordinates. Color differences (ΔE) among surface modifications were calculated and repeated measurements were analyzed using one-way anova and Bonferroni post-hoc test (α=.05).
Results: The color coordinates differ significantly between the color measuring devices used (p<.05). The modifications of the ceramic surface and the translucency shows a significant influence on the color coordinates (p<.05) of both devices. The color differences (ΔE) between the surface groups differ by shade measuring device and translucency. Nevertheless the ΔE values never crosses the threshold value for a clinically unacceptable color difference of ΔE>3.7.
Conclusions: The modification of the ceramic surface has a definite effect on the final color of the all-ceramic system tested. However, the mean ΔE values were always under the threshold value for a clinically unacceptable color difference (ΔE<3,7). Therefore these color measurement devices are suited to specify the color of the restoration within the process of fabrication and enhance the predictability of color reproduction.