The effect of repeated firings on the color of zirconia-based all-ceramic system / 대한치과보철학회지

ABSTRACT

PURPOSE: The aim of this study was to evaluate the effect of repeated firings on the color of zirconia restoration with different shading method. MATERIALS AND METHODS: Three different types of zirconia frameworks (adding metallic pigments to the initial zirconia powder before sintering (Group NM), dipping the milled frameworks in dissolved coloring agents (Group KI), or application of liner material to the sintered white frameworks (Group KW) were used to support A3 shade dentin porcelain. Repeated firings (3, 5, or 7) were performed, color differences among ceramic specimens were measured using a colorimeter. Repeated measurements analysis of variance (ANOVA) was used to analyze the data for significant difference. The Tukey Honestly Significant Different (HSD) test was used to perform multiple comparisons (alpha = .05). RESULTS: 1. L*a*b* values of the ceramic systems were affected by the number of firings (1, 3, 5 or 7 firings) (P 1) for group KW and KI fired after 3 times, except for group NM fired after 7 times. 4. In order of decreasing DeltaE value fired after 7 times, the values were group KI(DeltaE = 2.26) > group KW (DeltaE = 1.47) > group NM (DeltaE = 1.08) (P < .001). CONCLUSION: Repeated firings influenced the color of the zirconium-oxide all-ceramic specimens with different shading methods.