EP-4736808-A1 - ZIRCONIA PORCELAIN BLOCK, PREPARATION METHOD AND APPLICATION THEREOF

EP4736808A1EP 4736808 A1EP4736808 A1EP 4736808A1EP-4736808-A1

Abstract

A zirconia porcelain block, a preparation method and an application thereof are provided. The zirconia porcelain block includes an inner zirconia block and an outer zirconia block wrapping the inner zirconia block. The outer zirconia block includes a plurality of zirconia layers provided vertically in order of transparency, and the thickness of the zirconia layer with the maximum transparency and the thickness of the zirconia layer with the minimum transparency are both greater than the thickness of the zirconia layers between the maximum transparency and minimum transparency. The transparency of the inner zirconia block is the same as the maximum transparency of the plurality of zirconia layers, and the bottom end of the inner zirconia block is located in the zirconia layer with the minimum transparency. The height of the inner zirconia block is not less than two-thirds of the height of the outer zirconia block.

Inventors

LI, ZONGYU
LIU, WEI
ZHANG, YU
YANG, Qiangwen
ZHANG, XU
LIU, JIANJUN

Assignees

Shenzen Yurucheng Dental Materials Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20251030

Claims (10)

A zirconia porcelain block, characterized by comprising: an inner zirconia block made of a micron-sized zirconia mixture and an outer zirconia block made of a nanozirconia mixture wrapping the inner zirconia block; wherein the outer zirconia block comprises a plurality of zirconia layers provided sequentially in a vertical direction in order of transparency, a thickness of the zirconia layer with maximum transparency and a thickness of the zirconia layer with minimum transparency both are greater than a thickness of the zirconia layer between the maximum transparency and the minimum transparency; and a transparency of the inner zirconia block is the same as maximum transparency of the plurality of zirconia layers, a bottom end of the inner zirconia block is located in the zirconia layer with the minimum transparency, and a height of the inner zirconia block is no less than two-thirds of a height of the outer zirconia block.
The zirconia porcelain block according to claim 1, wherein the inner zirconia block is a zirconia block with an arched cross section.
The zirconia porcelain block according to claim 1, wherein the inner zirconia block is made of a zirconia mixture with a particle size between 0.2 µm to 0.5 µm, and the outer zirconia block is made of a zirconia mixture with a particle size between 10 nm to 80 nm.
The zirconia porcelain block according to claim 3, wherein the zirconia mixture of the outer zirconia block comprises high light-transmitting powder with transparency of 57% and low light-transmitting powder with transparency of 43%, and each of the zirconia layers is made by mixing the high light-transmitting powder and the low light-transmitting powder in a certain proportion.
The zirconia porcelain block according to claim 4, wherein the zirconia mixture comprises following components in parts by weight: 90 to 95 parts of ZrO 2 , 5 to 8 parts of Y 2 O 3 , 0.01 to 0.3 parts of Fe 2 O 3 , 0.01 to 0.3 parts of Er 2 O 3 , 0 to 0.2 parts of Mn 2 O 3 and 0 to 0.5 parts of Al 2 O 3 .
The zirconia porcelain block according to claim 1, wherein the thickness of the zirconia layer with the maximum transparency and the thickness of the zirconia layer with the minimum transparency among the plurality of zirconia layers are the same.
A method for preparing a zirconia porcelain block, characterized by comprising: obtaining inner layer zirconia powder of an inner zirconia block having same maximum transparency as outer layer zirconia powder, and pre-pressing the inner layer zirconia powder to form an inner zirconia green body; obtaining outer layer zirconia powder with different transparencies for preparing a zirconia layer, providing sequentially a plurality of zirconia layers wrapping the inner zirconia green body from bottom to top in an axial direction of the inner zirconia green body in order of transparency of the outer zirconia powder from small to large, and dry-pressing the inner zirconia green body and the plurality of zirconia layers as a whole to form a zirconia porcelain block green body; cold isostatic pressing the zirconia porcelain block green body; and sintering the zirconia porcelain block green body after cold isostatic pressing to obtain the zirconia porcelain block.
The method for preparing the zirconia porcelain block according to claim 7, wherein a pre-pressing pressure of the inner zirconia green body is no greater than 5 MPa, an overall dry-pressing pressure is 60 MPa to 70 MPa, and a pressure maintaining time is 10 seconds to 40 seconds; and a cold isostatic pressing pressure is 100 MPa to 300 MPa, a pressure maintaining time is 10 minutes to 15 minutes, and a sintering temperature is 1000°C to 1100°C.
The method for preparing the zirconia porcelain block according to claim 7, wherein a thickness of the zirconia layer with maximum transparency and a thickness of the zirconia layer with minimum transparency among the plurality of zirconia layers are both greater than a thickness of the zirconia layers between the maximum transparency and the minimum transparency, and a height of the inner zirconia block is no less than two-thirds of a sum of heights of the plurality of zirconia layers.
A denture made of the zirconia porcelain block according to any one of claims 1-6.

Description

TECHNICAL FIELD The present application relates to the technical field of denture materials, and in particular to a zirconia porcelain block, a preparation method and an application thereof. BACKGROUND Human teeth consist of a plurality of layers of structures from the inside out, including pulp, dentin and enamel. The strength of dentin is lower than that of enamel. Therefore, during normal chewing and abrasion, the dentin can buffer the wear of enamel, thus preventing teeth from being broken by sudden huge force. The material currently used for mid-end and low-end dental zirconia all-porcelain restorations is a single homogeneous material, which has the same strength from the inside to the outside. Without the buffering dentin, the service life of the denture is reduced. In appearance, it also shows certain color and transparency, which cannot well simulate the aesthetics of the gradient of teeth and the mechanical effects of different hardness inside and outside the teeth. SUMMARY In order to solve existing shortcomings, the present application provides a zirconia porcelain block, a preparation method and an application thereof. The technical solution adopted by the present application to solve the technical problems is as follows. The zirconia porcelain block includes an inner zirconia block made of a micron-sized zirconia mixture and an outer zirconia block made of a nanozirconia mixture wrapping the inner zirconia block. The outer zirconia block includes a plurality of zirconia layers provided sequentially in a vertical direction in order of transparency, a thickness of the zirconia layer with maximum transparency and a thickness of the zirconia layer with minimum transparency both are greater than a thickness of the zirconia layer between the maximum transparency and the minimum transparency; and a transparency of the inner zirconia block is the same as maximum transparency of the plurality of zirconia layers, a bottom end of the inner zirconia block is located in the zirconia layer with the minimum transparency, and a height of the inner zirconia block is no less than two-thirds of a height of the outer zirconia block. In an embodiment, the inner zirconia block is a zirconia block with an arched cross section. In an embodiment, the inner zirconia block is made of a zirconia mixture with a particle size between 0.2 µm to 0.5 µm, and the outer zirconia block is made of a zirconia mixture with a particle size between 10 nm to 80 nm. In an embodiment, the zirconia mixture of the outer zirconia block includes high light-transmitting powder with transparency of 57% and low light-transmitting powder with transparency of 43%, and each of the zirconia layers is made by mixing the high light-transmitting powder and the low light-transmitting powder in a certain proportion. In an embodiment, the zirconia mixture includes the following components in parts by weight: 90 to 95 parts of ZrO2, 5 to 8 parts of Y2O3, 0.01 to 0.3 parts of Fe2O3, 0.01 to 0.3 parts of Er2O3, 0 to 0.2 parts of Mn2O3 and 0 to 0.5 parts of Al2O3. In an embodiment, the thickness of the zirconia layer with the maximum transparency and the thickness of the zirconia layer with the minimum transparency among the plurality of zirconia layers are the same. The present application further provides a method for preparing a zirconia porcelain block, including: obtaining inner layer zirconia powder of an inner zirconia block having same maximum transparency as outer layer zirconia powder, and pre-pressing the inner layer zirconia powder to form an inner zirconia green body; obtaining outer layer zirconia powder with different transparencies for preparing a zirconia layer, providing sequentially a plurality of zirconia layers wrapping the inner zirconia green body from bottom to top in an axial direction of the inner zirconia green body in order of transparency of the outer zirconia powder from small to large, and dry-pressing the inner zirconia green body and the plurality of zirconia layers as a whole to form a zirconia porcelain block green body; cold isostatic pressing the zirconia porcelain block green body; andsintering the zirconia porcelain block green body after cold isostatic pressing to obtain the zirconia porcelain block. In an embodiment, a pre-pressing pressure of the inner zirconia green body is no greater than 5 MPa, an overall dry- pressing pressure is 60 MPa to 70 MPa, and a pressure maintaining time is 10 seconds to 40 seconds; and a cold isostatic pressing pressure is 100 MPa to 300 MPa, a pressure maintaining time is 10 minutes to 15 minutes, and a sintering temperature is 1000°C to 1100°C. In an embodiment, a thickness of the zirconia layer with maximum transparency and a thickness of the zirconia layer with minimum transparency among the plurality of zirconia layers are both greater than a thickness of the zirconia layers between the maximum transparency and the minimum transparency, and a height of the inner zirconia block is n