COMPOSITION AND METHOD FOR GENERATING A SHADE GRADIENT IN ZIRCONIA DENTAL RESTORATION
Disclosed are compositions and methods for bleaching and optionally coloring a shaded zirconia, particularly mono-chromatic pre-shaded dental zirconia. The compositions and methods are useful in generating a shade gradient in milled dental restorations. The compositions comprise metal salts or complex dissolved in a solvent.
1 . A liquid for bleaching pre-shaded zirconia, the liquid comprising:
a metal compound or metal compounds comprising one or more metal selected from zinc, gallium, and aluminum in an amount sufficient to cause bleaching; and optionally solvent,
wherein the liquid reduces the intensity of color in the pre-shaded zirconia to generate a shade gradient in a dental restoration.
2 . The liquid of claim 1 , wherein the metal compound is a metal salt or complex comprising a metal and a counterpart selected from halides (Cl, F, Br, and I), nitrate, acetate, sulfate, lactate, propionate, formate, and alkoxides.
3 . The liquid of claim 1 , wherein the metal compound is a solid salt or complex of zinc, aluminum, or gallium and is present at about 0.1 wt % to about 80 wt % by weight of the bleaching liquid.
4 . The liquid of claim 1 , wherein the metal compound is a liquid metal compound of zinc, aluminum, or gallium and is present at about 0.1 wt % to about 100 wt % of the bleaching liquid.
5 . The liquid of claim 1 , wherein the metal comprises zinc.
6 . The liquid of claim 1 , wherein the metal comprises gallium.
7 . The liquid of claim 1 , wherein the metal comprises aluminum.
8 . The liquid of claim 2 , wherein the metal compound comprises zinc, gallium, and aluminum.
9 . The liquid of claim 2 , wherein the metal salt or complex is selected from:
Conc.
salt/complex
(wt %)
ZnCl 2
1-80
Zn(NO 3 ) 2 •6H 2 O
1-80
Ga(NO 3 ) 3 •xH 2 O
1-80
Al(NO 3 ) 3 •9H 2 O
1-80
10 . The liquid of claim 1 , wherein the metal compound is a zinc salt or zinc complex.
11 . The liquid of claim 1 , wherein the metal compound is a gallium salt or gallium complex.
12 . The liquid of claim 1 , wherein the metal compound is an aluminum salt or aluminum complex.
13 . The liquid of claim 1 , further comprising at least one coloring agent.
14 - 19 . (canceled)