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 effectiv e method for surface characterization of ceramic restorations. This study e valuated colour change after glazing procedures for six commonly used stain s from this novel system. One hundred and five ceramic specimens were made of the same enamel porcelain powder and standardized in size. The stains we re applied on ceramic blocks and light-cured according to the manufacturer' s recommendations. Porcelain colour was then measured with a calibrated col orimeter before and after each glazing procedure. The CIE-L*a*b* colour co- ordinates were obtained as a measure of the direction and magnitude of colo ur change. Colour changes were noted for all six stains when subjected to t he first glazing procedure (DeltaE* = 1.25-4.73). Brown, orange and green s tains showed the greatest colour shifts (DeltaE* > 3.3), which might be con sidered clinically significant. However, the colour change is not of the sa me pattern in the colour space. Compared with the first glazing procedure, the second and third glazing procedures demonstrated less effect on the col our stability of the stains (DeltaE*=0.361-1.2). The results provide import ant information about colour shifts in the system, which require overcorrec tion during stain application.