Evaluation of the colour stability of different ceramic materials with two thicknesses

Society places a great emphasis on aesthetics, & there is a constant rise in the demands placed on dental restorations' aesthetics. The aim of this in-vitro research was to study the impact of the finishing protocol on the color stability parameter of different glass-ceramic materials with two different thicknesses, before & after thermocyling. One hundred twelve specimens had been prepared with standard dimensions of one mm & two mm thickness & ten mm diameter for the four different glass-ceramic materials. The ceramic specimens had been separated into 4groups according to ceramic material (n=28): IPS e.max Press, CeraMotion, Rosetta SP & CeltraPress, each group had been subdivided into two sub-groups according to the specimen thickness (n=14): 1 mm and 2 mm. Each sub-group was further split into 2 divisions according to the finishing protocol (n=7): glazed only & polished then glazed. The results of our study all samples have shown color change within visually perceptible but clinically acceptable level (more than 1 and less than 3.7), emax glazed samples (1mm&2mm) together with emax glazed and polished samples (1mm) have shown significantly higher ΔE beyond the clinically acceptable level. Increasing ceramic thickness from 1 mm to 2 mm has shown better color stability in Emax group. Polishing before glazing increased color stability in Emax while decreased it in Celtra.