Colour stability of low fusing porcelains: an in vitro study

Abstract

Developing porcelain manufacturing technology provides lower fusing porcelains to avoid thermal stresses in metal substructure, particularly for titanium and gold alloys. So far, aesthetic properties of low fusing ceramics have not been well documented. The purpose of this study was, therefore, to estimate the long-term colour stability of low fusing ceramics by using an accelerated aging procedure. Four different ceramics (Vita Omega 900, Vita Titankeramik, Ceramco Finesse, Ceramco II) were used. Porcelain samples 11 +/- 0.5 mm in diameter and 1.4 +/- 0.2 mm in thickness were prepared in three commonly used shades to provide 10 samples of each group. The samples were fired in accordance with the recommendations of the manufacturers. CIE Lab readings were recorded with a spectrophotometer prior to experiments and after a 100 h accelerated aging. The results revealed that only Ceramco Finesse porcelain had a colour change (DeltaE > 1) that is noticeable by human eye. When the shades of porcelains were compared, C3 had greater colour change compared with A3 and B3 shades (P < 0.05).

Color and Luminescence Stability of Selected Dental Materials In Vitro

“…Haselton et al 30 suggested that ΔE ab = 3.7, whereas Kolbeck et al 31 assumed it as ΔE ab = 1.5. According to some other researchers the threshold is ΔE ab = 1 32–34 . However, in contrast, Guan et al 35 and Tung et al 29 assume that the maximum color difference acceptable in dental materials is ΔE = 2, while others claim that this value is ΔE ab = 3.3 33,36 .…”

Effect of Accelerated Aging on the Color and Opacity of Resin Cements

“…The manufacturer of the weathering instrument has estimated that 300 hours of aging is equivalent to one year of clinical service. 18 Khokhar and others stated that the greatest amount of color change occurred in the first 100 hours of accelerated aging. 7 In the current study, 100 hours of accelerated aging was found to be satisfactory for demonstrating the early color change of the resin cement.…”

Effects of fibers on the color change and stability of resin composites after accelerated aging

“…To relate the quantity of color change (∆E) recorded by the colorimeter to a clinical environment, color change data were converted to National Bureau of Standards (NBS) units as follows: NBS unit=0.92×∆E 26,27) . The defined critical remarks of color change according to the quantified NBS units are given in Table 2.…”