Colour stability of porcelain repair materials with accelerated ageing.

The purpose of this study was to measure and compare the colour stability of three porcelain repair materials (Charizma, Clearfil and Silux Plus) with an all-ceramic material following accelerated ageing. Three composites and one ceramic control were subjected to accelerated ageing for a period of 300 h. Initial specimen colour parameters were determined in the Commission International de I'Eclairage Lab (CIELAB) colour order system with a colorimeter. Colour changes were calculated before (DeltaE) and after 300 h of accelerated ageing (DeltaE*). Colour difference data were subjected to one-way analysis of variance (anova) followed by Duncan's test to examine the interaction between material and time interval of ageing. There were no significant difference between DeltaL values of Porcelain-Charizma and Porcelain-Silux Plus. All mean DeltaL* values were negative after 300 h ageing. Porcelain-Silux Plus demonstrated the highest DeltaL* of the investigated groups. There were significant differences between baseline 300-h aged specimens with respect to Deltaa*, Deltaa for either of the investigated materials. For Silux Plus, Deltaa and Deltaa* values were significantly higher than the others. Significant differences were observed between baseline and 300-h values for Deltab and Deltab*. Deltab and Deltab* values were significantly higher for Silux Plus. There were significant differences between baseline and 300-h values of colour difference, DeltaE, DeltaE*. Highest DeltaE* value was obtained using the microfilled composite, Silux Plus. Lowest value of DeltaE was recorded with the hybrid composite, Charizma.