Effect of number of firings on the color and translucency of ceramic core materials with veneer ceramic of different thicknesses.

Statement Of Problem: Whether masking or translucency should be the goal for achieving an esthetic restoration with ceramic materials is unknown.

Purpose: The purpose of this in vitro study was to examine the effect of the number of firings on the color and translucency of ceramic core material with different thicknesses of veneer ceramic.

Material And Methods: Three different ceramic systems were used: IPS Empress (IE), IPS e.max Press (IEP), and Turkom Cera (TC). Ninety disk-shaped cores, 10 mm in diameter and 0.8 mm in thickness were prepared using each system (n=30). The specimens were divided into 3 subgroups (n=10) according to the thickness of the veneering ceramic: 0.5, 1.0, and 1.5 mm. The specimens were fired 1, 3, and 5 times, and the color parameters of the specimens were measured. The color measurements were repeated, and the data were statistically evaluated using 2-way and multifactorial analysis of variance, the Duncan test, and the Bonferroni post hoc test.

Results: The number of firings affected the translucency parameter and CIELab values. Increased porcelain thickness led to decreased translucency parameter and L* values and increased a* and b* values (P<.05). The IE system was the most translucent (P<.001). The changes with increased firing periods were not statistically significant (P>.05). The number of firings affected the color change of the IE and IEP systems but not of the translucency parameter system.

Conclusions: Repeated firings and porcelain thickness affected the final color and translucency of the ceramic systems tested. These 2 factors adversely affected the esthetic result and should be considered in both the preparation and the laboratory phase.