Colour stability of low fusing porcelains:: an in vitro study

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 (Delta E > 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).