Impact of background on color, transmittance, and fluorescence of leucite based ceramics

Abstract

This study evaluated the impact of tooth shade on differences in color (∆E), lightness (∆L), chromaticity coordinates a*/b* (∆a and ∆b), transmittance and the degree of fluorescence of CAD/CAM leucite based ceramic (LBC). Ten disks were fabricated of LBC; Empress CAD, A2, thickness of 1.5 mm and eight disks of resin-nano-ceramic (RNC; Lava Ultimate) in different colors to simulate variations in substrate shade. The associations of LBC disks with different color substrates were analyzed with a spectrophotometer; ∆E, ∆L*, ∆a*, ∆b*, and transmittance were measured and calculated. Fluorescence was evaluated with a fluorescence system (Fluorescence System, Biopdi). All substrate shades influenced the optical properties of LBC, with regard to color, luminosity, coordinate a* and b*, transmittance, and fluorescence (p<0.001). Substrate colors with high saturation (A3.5 and C2) presented highest impact, whereas colors with lowest saturations (BL, B1) showed less impact. Substrate color influenced the optical properties of ceramic restorations.

Fluorescence of natural teeth and restorative materials, methods for analysis and quantification: A literature review

“…The studies cited above employ various devices and methods to analyze and quantify fluorescence intensity in aesthetic materials (Table ). Authors have analyzed the fluorescence by means of computational measurement of images obtained with photographic cameras, or devices that capture and photograph fluorescence . The photographs are made under UV light using filters so that the image obtained contains the information on the tooth and/or the tested material .…”

“…To date, studies evaluating, quantifying and comparing the fluorescence intensity of dental ceramic materials are rather scarce (Table ) . The first fluorescent ceramics used uranium as a luminophore, and it was introduced into porcelain in combination with cerium oxide, thus producing a bluish‐white fluorescence very close to that of natural teeth .…”

“…Moreover, when the degree of saturation of the ceramic increased, the fluorescence varied with the relative increase in the lines' amplitude in relation to the bands, and the resulting color was close to yellow‐greenish . When we look for scientific information on the fluorescence of current ceramic systems, only one investigation is available to date . This lack of information makes the behavior of fluorescence in these materials difficult to understand, and represents a gap in this area of knowledge.…”

“…In 2017, a study evaluated the color, translucency, and fluorescence of lithium disilicate samples that were superimposed on different color substrates. The association of ceramic with substrates, especially darker substrates, resulted in a reduction in fluorescence intensity . Traditional zirconia is a nonfluorescent material.…”

“…To date, studies evaluating, quantifying and comparing the fluorescence intensity of dental ceramic materials are rather scarce (Table 2). [45][46][47][69][70][71][72][73] The first fluorescent ceramics used uranium as a luminophore, and it was introduced into porcelain in combination with cerium oxide, thus producing a bluish-white fluorescence very close to that of natural teeth. 74 However, since the salts and isotopes of uranium are highly radioactive, it has been banned from dental use and replaced by other luminescent species such as europium, terbium, cerium, and ytterbium.…”