Influence of firing times and temperature on color stability of low-fusing porcelains for high-functional gold alloys

The purpose of this study was to investigate the effect of firing conditions on color stability. Three commercially available porcelains for high functional gold alloys, Carrara (CA), Deguceram Gold (DE) and Duceragold (DU) were used. In this study color stability was investigated under fire treatment of 1st, 3rd, 5th times and firing temperatures of 0, 20, and 40 degrees C higher than the manufactures standard temperature (CA: 845 degrees C, DE: 780 degrees C, DU: 780 degrees C). L* was degreased in CA 5 times, DE 3 times, DU by repeated firing. No difference was observed among L* of firing temperatures DE and DU, but L* was degreased in CA with firing temperatures of 40 degrees C higher. a* was degreased in CA, DU, DE with repeated firing, a* was degreased 5 times at firing temperatures of higher. b* was degreased in DU, but b* was increased in CA and DE with 5 firings. b* was increased with 5 findings at firing temperatures of 40 degrees C higher.