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Multi-layered Zirconia Dental Mill Blank and Process of Production

IP.com Disclosure Number: IPCOM000248276D
Publication Date: 2016-Nov-14

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention relates to a porous multi-layered coloured zirconia dental mill blank comprising a bottom layer B having the composition COMP-B which comprises ceramic components CER-COMP-B, colouring components COL-COMP-B and stabilizing components STAB-COMP-B, a top layer E having the composition COMP-E which comprises ceramic components CER-COMP-E, colouring components COL-COMP-E stabilizing components STAB-COMP-E, at least one intermediate layer Ex having the composition COMP-E of top layer E, at least one intermediate layer Bx having the composition COMP-B of bottom layer B, x being an integer and indicating the number of intermediate layers, wherein the layers with compositions COMP-B and COMP-E are arranged in alternating order, and wherein the thickness of the individual layers B, Bx is decreasing from bottom to top and the thickness of the individual layers E, Ex is decreasing from top to bottom. The dental mill blank can be used for producing dental articles.

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Multi-layered Zirconia Dental Mill Blank and Process of Production

Abstract

The invention relates to a porous multi-layered coloured zirconia dental mill blank comprising a bottom layer B having the composition COMP-B which comprises ceramic components CER- COMP-B, colouring components COL-COMP-B and stabilizing components STAB-COMP-B, a top layer E having the composition COMP-E which comprises ceramic components CER-COMP-E, colouring components COL-COMP-E stabilizing components STAB-COMP-E, at least one intermediate layer Ex having the composition COMP-E of top layer E, at least one intermediate layer Bx having the composition COMP-B of bottom layer B, x being an integer and indicating the number of intermediate layers, wherein the layers with compositions COMP-B and COMP-E are arranged in alternating order, and wherein the thickness of the individual layers B, Bx is decreasing from bottom to top and the thickness of the individual layers E, Ex is decreasing from top to bottom. The dental mill blank can be used for producing dental articles.

Field of the Invention

The invention relates to a pre-coloured zirconia dental mill blank having a layered structure. The invention also relates to a process of producing such a dental mill blank, a process of producing a dental restoration out of such a dental mill blank and dental articles obtained or obtainable by applying such a process.

Background Art

Dental mill blanks based on zirconia ceramic materials are described in various documents and are also commercially available.

Dental mill blanks are typically used for producing dental restorations (e.g. crowns and bridges) by a milling process. The zirconia material, the dental mill blank is made of, is typically in a pre-sintered and porous stage which facilitates its milling. The obtained dental article is then sintered to its final density before it is placed in the mouth of the patient.

A natural appearing tooth shows a colour and translucency gradient from dentin to enamel.

Enamel is more translucent and less colour intense compared to the dentin and therefore the top enamel area of a tooth is looking brighter compared to the bottom part of a tooth.

Pure zirconia, however, is white and does not match to the natural colour of the tooth in the mouth of a patient.

To address this issue, the milled zirconia dental ceramic is often treated with colouring solutions before sintering.

Another approach suggests to use zirconia mill blanks containing multiple coloured layers, so called multi-layer mill blanks, for producing dental restoration.

But using only two differently coloured materials does not give a natural gradient and therefore mill blanks with four or more differently coloured layers are suggested.

However, manufacturing a multi-layer mill blank containing many differently shaded raw materials makes the product expensive and the manufacturing process complicated.

There is some patent literature related to this topic:

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