Colour stability of a new light-cured ceramic stain system subjected to glazing temperature.

A light-cured ceramic stain system (Orbit LC) offers promise as an effective method for surface characterization of ceramic restorations. This study evaluated colour change after glazing procedures for six commonly used stains from this novel system. One hundred and five ceramic specimens were made of the same enamel porcelain powder and standardized in size. The stains were applied on ceramic blocks and light-cured according to the manufacturer's recommendations. Porcelain colour was then measured with a calibrated colorimeter before and after each glazing procedure. The CIEL*a*b* colour co-ordinates were obtained as a measure of the direction and magnitude of colour change. Colour changes were noted for all six stains when subjected to the first glazing procedure (DeltaE* = 1.25-4.73). Brown, orange and green stains showed the greatest colour shifts (DeltaE* > 3.3), which might be considered clinically significant. However, the colour change is not of the same pattern in the colour space. Compared with the first glazing procedure, the second and third glazing procedures demonstrated less effect on the colour stability of the stains (DeltaE* = 0.36-1.12). The results provide important information about colour shifts in the system, which require overcorrection during stain application.