Effect of Repeated Firings the Colour of Porcelain

An invitro study

Abstract

Context: Dental ceramics are one of the widely used esthetic restorative materials and these are attractive because of their biocompatibility, long term color stability. Duplicating the appearance of tooth structure is a complex process that requires careful control of the form, surface texture, translucency and color of the restoration. Repeated firings of dental porcelain may change porcelain shades.

Aims & Objectives: To evaluate and compare the effect of multiple firings on metal ceramics before and after glazing

Materials and methods: A total of 70 base metal alloy disks with a thickness of 0.5mm were made. Then oxidation, opaque porcelain application and firing, followed by dentin porcelain is applied to all specimens and subjected to 1^st and 2^nd dentin firings. They were subdivided into 7groups (n=10). 1^st group is the control group and other groups were subjected to repeated second dentin firings for 3,4,5,6,7 and 8 dentin firings and analysed for color with spectrophotometer. All the specimens were glazed and again analysed for color.

Results: The color difference was observed at 5^th dentin firing before glazing and at 8^th dentin firings after glazing compared to control group.

Conclusion: Color and microhardness are noticeably affected by repeated firings.

Keywords: Color, ceramics