The effect of repetitive firings on the color of an alumina ceramic system with varying ceramic shade and thickness

Abstract

Objective The color of all‐ceramic restorations is one of the main criteria to achieve esthetical success. Many factors such as ceramic thickness, condensation techniques, firing temperature, and numbers can affect the final color of restoration. The purpose of this study was to investigate the color changes in alumina‐based ceramic system according to ceramic shade and thickness during the multiple firings. Materials and Methods Sixty disc‐shaped specimens with two different veneering porcelain shades (A1 or A3), and with three different ceramic thicknesses (0.5, 1, or 1.5 mm), were fabricated from an alumina‐based ceramic system. Multiple firings (3, 5, 7, or 9 firings) were performed, and color changes (ΔE00) were determined using a spectrophotometer. Repeated‐measures ANOVA were used to analyze the data. The Duncan test was used for multiple comparisons (α = .05). Results The L*a*b* values of the specimens were affected by the number of firings (3, 5, 7, or 9), veneering ceramic shades (A1 or A3) and veneering ceramic thicknesses (0.5, 1, or 1.5 mm). Significant interactions were present between the number of firings, veneering ceramic shade, and veneering ceramic thickness for L* (p < .001), a* (p < .001), and b* (p < .001) values. Conclusions No statistically significant color change was observed between 3rd and 9th firings. Clinical Significance Veneering ceramic shade, veneering ceramic thickness, and number of firings should be carefully considered to obtain an acceptable color match of the definitive restorations.

Effect of Consecutive Firings on the Optical and Mechanical Properties of Silicate and Lithium Disilicate Based Glass‐Ceramics

“…Additionally, Barghi 12 observed that there was a slight change in color with the increase in the number of firings, but this difference was dependent on the type of porcelain used; moreover, the color remained stable after five firings. Studies which obtained alteration in color parameters emphasized that they were still within acceptable levels 3,7,9,13,31–36 . A study that evaluated lithium disilicate after seven firings noticed a small change in color (ΔE = 1.61) and related it to the highest homogeneity of the CAD/CAM material 3 …”

The Effect of Repeated Pressing on the Flexural Strength, Color Stability, Vickers Hardness, and Surface Topography of Heat-Pressed Lithium Disilicate

“…Despite the significant difference of the values of the color coordinates, ∆E values of ∆E 1–2 = 2.04 and ∆E 1–3 = 2.14 after the second and third pressing cycles, respectively, indicate the acceptable color stability of the repressed materials. In the dental literature, it is widely acknowledged that ΔE values below 2.7–3.3 are clinically acceptable [ 27 , 28 , 29 ]. The ΔE values of the current study were lower than those reported by ElNaggar et al [ 30 ], who reported a ΔE value of 3.78.…”