PRE-SINTERED CERAMIC BLOCK FOR DENTAL RESTORATION, PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

Disclosed is a pre-sintered ceramic block for a dental restoration, which has a low pre-sintering temperature, contains a silica main crystal phase, but does not contain or contains a small amount of lithium metasilicate crystal phase. The pre-sintered ceramic block has a low hardness, with a Vickers hardness of 0.5-3 GPa, which is significantly lower than that of a ceramic block containing a lithium metasilicate crystal phase, and same is suitable for dry machining and also wet machining when being machined into a dental restoration. (FIG. 2)

Claims

1. A pre-sintered ceramic block for a dental restoration, wherein the pre-sintered ceramic block contains a silica main crystal phase, has a Vickers hardness of 0.5-3 GPa, and is opaque.

2. The pre-sintered ceramic block according to claim 1, wherein the pre-sintered ceramic block has a three-point bending strength of 10-110 MPa.

3. The pre-sintered ceramic block according to claim 1, wherein the pre-sintered ceramic block does not contain a lithium metasilicate crystal phase.

4. The pre-sintered ceramic block according to claim 1, comprising the following components: SiO.sub.2 55-85% wt, Li.sub.2O: 10-25% wt, ZrO.sub.2 0-10% wt, Al.sub.2O.sub.3: 0.3-8% wt, La.sub.2O.sub.3: 0-7% wt, ZnO: 0-10% wt, K.sub.2O: 0.1-10% wt, GeO.sub.2: 0.1-7% wt, nucleating agent: 0-10% wt, colorant: 0-10% wt, other additives: 0-15% wt; wherein the nucleating agent is one of or a combination of at least two of P.sub.2O.sub.5, TiO.sub.2, V.sub.2O.sub.5, Cr.sub.2O.sub.3, and Fe.sub.2O.sub.3; the other additives are one of or a combination of at least two of B.sub.2O.sub.3, F, Na.sub.2O, BaO, SrO, CaO, and MgO.

5. The pre-sintered ceramic block according to claim 4, wherein the colorant is a glass colorant or a ceramic colorant.

6. A method for preparing the pre-sintered ceramic block according to claim 1, comprising the steps of: (1) preparing a matrix glass powder; (2) putting the prepared matrix glass powder into a mould, and carrying out pressing molding to obtain a matrix glass body; and (3) pre-sintering the matrix glass body under a vacuum condition to obtain a pre-sintered ceramic block, wherein a sintering temperature during pre-sintering is 530-590° C.

7. The method for preparing the pre-sintered ceramic block according to claim 6, wherein the matrix glass powder comprises the following components: SiO.sub.2 55-85% wt, Li.sub.2O: 10-25% wt, ZrO.sub.2 0-10% wt, Al.sub.2O.sub.3: 0.3-8% wt, La.sub.2O.sub.3: 0-7% wt, ZnO: 0-10% wt, K.sub.2O: 0.1-10% wt, GeO.sub.2: 0.1-7% wt, nucleating agent: 0-10% wt, colorant: 0-10% wt, other additives: 0-15% wt; wherein the nucleating agent is one of or a combination of at least two of P.sub.2O.sub.5, TiO.sub.2, V.sub.2O.sub.5, Cr.sub.2O.sub.3, and Fe.sub.2O.sub.3; the other additives are one of or a combination of at least two of B.sub.2O.sub.3, F, Na.sub.2O, BaO, SrO, CaO, and MgO.

8. The method for preparing the pre-sintered ceramic block according to claim 6, wherein the sintering temperature during pre-sintering is 530-560° C.

9. The method for preparing the pre-sintered ceramic block according to claim 6, wherein a holding time for pre-sintering is 20-240 min.

10. A pre-sintered ceramic block for a dental restoration, wherein the pre-sintered ceramic block contains a silica main crystal phase, has a Vickers hardness of 0.5-3 GPa, is opaque, and exhibits a gradual transmittance and/or color after dense-sintering of 800-1100° C.

11. The pre-sintered ceramic block according to claim 10, wherein the pre-sintered ceramic block has a three-point bending strength of 10-110 MPa.

12. The pre-sintered ceramic block according to claim 10, wherein the pre-sintered ceramic block does not contain a lithium metasilicate crystal phase.

13. The pre-sintered ceramic block according to claim 10, comprising the following components: SiO.sub.2 55-85% wt, Li.sub.2O: 10-25% wt, ZrO.sub.2 0-10% wt, Al.sub.2O.sub.3: 0.3-8% wt, La.sub.2O.sub.3: 0-7% wt, ZnO: 0-10% wt, K.sub.2O: 0.1-10% wt, GeO.sub.2: 0.1-7% wt, nucleating agent: 0-10% wt, colorant: 0-10% wt, other additives: 0-15% wt; wherein the nucleating agent one of or a combination of at least two of P.sub.2O.sub.5, TiO.sub.2, V.sub.2O.sub.5, Cr.sub.2O.sub.3, and Fe.sub.2O.sub.3; the other additives are one of or a combination of at least two of B.sub.2O.sub.3, F, Na.sub.2O, ZrO.sub.2, BaO, SrO, CaO, and MgO.

14. The pre-sintered ceramic block according to claim 13, wherein the colorant is a glass colorant or a ceramic colorant.

15. A method for preparing the pre-sintered ceramic block according to claim 10, comprising the steps of: (1) preparing at least two matrix glass powders with different transmittance and/or color; (2) putting the prepared at least two matrix glass powder into a mould in the order of transmittance and/or color gradient, and carrying out pressing molding to obtain a matrix glass body; and (3) pre-sintering the matrix glass body under a vacuum condition to obtain a pre-sintered ceramic block, wherein a sintering temperature during pre-sintering is 530-590° C.

16. The method for preparing the pre-sintered ceramic block according to claim 15, wherein the matrix glass powder comprises the following components: SiO.sub.2 55-85% wt, Li.sub.2O: 10-25% wt, ZrO.sub.2 0-10% wt, Al.sub.2O.sub.3: 0.3-8% wt, La.sub.2O.sub.3: 0-7% wt, ZnO: 0-10% wt, K.sub.2O: 0.1-10% wt, GeO.sub.2: 0.1-7% wt, nucleating agent: 0-10% wt, colorant: 0-10% wt, other additives 0-15% wt; wherein the nucleating agent is one of or a combination of at least two of P.sub.2O.sub.5, TiO.sub.2, V.sub.2O.sub.5, Cr.sub.2O.sub.3, and Fe.sub.2O.sub.3; the other additives are one of or a combination of at least two of B.sub.2O.sub.3, F, Na.sub.2O, BaO, SrO, CaO, and MgO.

17. The method for preparing the pre-sintered ceramic block according to claim 15, wherein the sintering temperature during pre-sintering is 530-560° C.

18. The method for preparing the pre-sintered ceramic block according to claim 15, wherein a holding time for pre-sintering is 20-240 min.

19. A method for preparing a ceramic block for a dental restoration, comprising the steps of: preparing the pre-sintered ceramic block of claim 1; and dense-sintering the pre-sintered ceramic block under a vacuum condition; wherein a temperature during dense-sintering is 800-1100° C.

20. A method for preparing a dental restoration, comprising the steps of: preparing the pre-sintered ceramic block of claim 1; processing the pre-sintered ceramic block into a dental restoration shape to obtain a restoration body; and dense-sintering the restoration body under a vacuum condition to obtain a dental restoration; wherein a temperature during dense-sintering is 800-1100° C.

21. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0153] To describe the technical solutions in the examples of the present application and the prior art more clearly, the following briefly describes the drawings required for the examples and the prior art. Obviously, the drawings in the following description show some examples of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative work.

[0154] FIG. 1 is an XRD pattern of a pre-sintered ceramic block prepared in Example 2;

[0155] FIG. 2 is an XRD pattern of a pre-sintered ceramic block prepared in Example 4; and

[0156] FIG. 3 is an XRD pattern of a pre-sintered ceramic block prepared in Example 17.

DETAILED DESCRIPTION OF THE INVENTION

[0157] To make the objectives, technical solutions, and advantages of this application more comprehensible, the following describes this application in detail with reference to embodiments and drawings. Obviously, the described embodiments are merely some but not all of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative efforts shall fall within the protection scope of this application.

Preparative Examples of Pre-Sintered Ceramic Blocks and Dental Restoration

EXAMPLE 1

[0158] The matrix glass powder comprises the following components and amounts:

SiO.SUB.2.: 67.1% wt

Li.SUB.2.O: 14.7% wt

ZrO.SUB.2.: 1.7% wt

[0159] Al.sub.2O.sub.3: 1.2% wt

K.SUB.2.O: 4.2% wt

[0160] P.sub.2O.sub.5: 3.3% wt

ZnO: 4.2% wt

CeO.SUB.2.: 0.9% wt

GeO.SUB.2.: 0.65% wt

MgO: 0.3% wt

[0161] La.sub.2O.sub.3: 0.9% wt
B.sub.2O.sub.3: 0.3% wt
V.sub.2O.sub.5: 0.25% wt
Er.sub.2O.sub.3: 0.1%
Tb.sub.4O.sub.7: 0.2% wt

MnO.SUB.2.: 0.08%

[0162] According to the components and the amounts of the matrix glass powder, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to all the components were ground and mixed uniformly, the mixed matrix raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm to obtain matrix glass powders.

[0163] The matrix glass powders were loaded into a mould, uniaxial dry pressing molding was carried out under a molding pressure of 75 MPa, and then a matrix glass body with the weight of about 9-10 g was obtained.

[0164] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 550° C. for 60 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block;

[0165] The pre-sintered ceramic block was subjected to wet machining using CAD/CAM machining equipment (CEREC inLab MC XL, SIRONA) to obtain a restoration body.

[0166] The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 875° C. for 15 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a lithium disilicate glass ceramic restoration.

EXAMPLE 2

[0167] According to the components and amounts of the monochromatic matrix glass powder 1 in Table 1, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to other components except for colorants (V.sub.2O.sub.5, Er.sub.2O.sub.3, MnO.sub.2) were ground and mixed uniformly, the mixed raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm, followed by adding the colorants and mixing uniformly; to obtain matrix glass powder 1.

[0168] In the same way, monochromatic matrix glass powder 2 and monochromatic matrix glass powder 3 were prepared. They are mixed uniformly according to mass ratio of monochromatic matrix glass powder 1: monochromatic matrix glass powder 2: monochromatic matrix glass powder 3=4:3:2, to obtain a matrix glass powder. The matrix glass powders were loaded into a mould, uniaxial dry pressing molding was carried out under a molding pressure of 75 MPa, and then a matrix glass body with the weight of about 9-10 g was obtained.

[0169] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 570° C. for 60 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block; the pre-sintered ceramic block was subjected to XRD detection, the result was shown in FIG. 1, and it can be seen from FIG. 1 that the pre-sintered ceramic block prepared in this example contains a silica main crystal phase and a lithium metasilicate secondary crystal phase.

[0170] The pre-sintered ceramic block was subjected to dry machining by using CAD/CAM machining equipment (Roland DWX 51D) to obtain a restoration body, the processed restoration was complete, and there were no problems with incomplete edges, incomplete processing, and damage to the ceramic blocks.

[0171] The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 930° C. for 10 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a lithium disilicate ceramic restoration.

TABLE-US-00001 TABLE 1 Monochromatic Monochromatic Monochromatic Compo- matrix glass matrix glass matrix glass nent powder 1 powder 2 powder 3 SiO.sub.2 69.60%  69.67%  69.67%  Li.sub.2O 14.42%  14.44%  14.44%  ZrO.sub.2 1.50% 1.50% 1.50% Al.sub.2O.sub.3 1.16% 1.26% 1.26% K.sub.2O 3.58% 3.58% 3.58% P.sub.2O.sub.5 4.00% 4.00% 4.00% ZnO 2.44% 2.45% 1.45% CeO.sub.2 1.15% 1.15% 1.15% GeO.sub.2 0.85% 0.85% 0.85% MgO 0.30% 0.30% 0.30% La2O3 0.60% 0.60% 0.60% V.sub.2O.sub.5 —  0.2% — ErO.sub.2  0.3% — — MnO.sub.2 — —  0.2%

EXAMPLE 3

[0172] According to the components and the amounts of the matrix glass powder 1 in Table 2, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to all the components were ground and mixed uniformly, the mixed raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm to obtain matrix glass powder 1, respectively.

[0173] In the same way, monochromatic matrix glass powder 2 and monochromatic matrix glass powder 3 were prepared. They are mixed uniformly according to a ratio of monochromatic matrix glass powder 1: monochromatic matrix glass powder 2: monochromatic matrix glass powder 3=4:3:2 to obtain a matrix glass powder.

[0174] The pre-sintered ceramic block was obtained by molding and pre-sintering according to the method of Example 2; and the lithium disilicate ceramic restoration was obtained by wet machining and dense-sintering on the pre-sintered ceramic block according to the method of Example 1.

TABLE-US-00002 TABLE 2 Monochromatic Monochromatic Monochromatic Compo- matrix glass matrix glass matrix glass nent powder 1 powder 2 powder 3 SiO.sub.2 69.81%  69.81%  69.81%  Li.sub.2O 14.47%  14.47%  14.47%  ZrO.sub.2  1.5%  1.5%  1.5% Al.sub.2O.sub.3 1.76% 1.26% 1.26% K.sub.2O 3.60% 3.60% 3.60% P.sub.2O.sub.5 4.01% 4.01% 4.01% ZnO 2.35%  7.4%  7.4% CeO.sub.2 1.05%  1.1% 1.15% GeO.sub.2 0.85% 0.85% 0.85% MgO  0.3%  0.3%  0.3% La2O3  0.5%  0.5%  0.5% V.sub.2O.sub.5 —  0.2% — ErO.sub.2  0.3% — — MnO.sub.2 — — 0.15%

EXAMPLE 4

[0175] The matrix glass powder comprises the following components and contents:

SiO.SUB.2.: 70.42% wt

Li.SUB.2.O: 14.97% wt

ZrO.SUB.2.: 0.74% wt

[0176] Al.sub.2O.sub.3: 1.01% wt

K.SUB.2.O: 2.58% wt

[0177] P.sub.2O.sub.5: 3.6% wt

ZnO: 3.9% wt

CeO.SUB.2.: 0.65% wt

GeO.SUB.2.: 1.03% wt

MgO: 0.2% wt

[0178] La.sub.2O.sub.3: 0.5% wt
V.sub.2O.sub.5: 0.15% wt
Er.sub.2O.sub.3: 0.2% wt

MnO.SUB.2.: 0.05% wt

[0179] According to the components and amounts of the matrix glass powder, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to other components except for colorants (V.sub.2O.sub.5, Er.sub.2O.sub.3, and MnO.sub.2) were ground and mixed uniformly, the mixed matrix raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm, followed by adding the colorants and mixing uniformly; to obtain a matrix glass powder.

[0180] The matrix glass powders were loaded into a mould, uniaxial dry pressing molding was carried out under a molding pressure of 75 MPa, and then a matrix glass body with a weight of about 9-10 g was obtained.

[0181] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 540° C. for 120 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block; the pre-sintered ceramic block was subjected to XRD detection, the result was shown in FIG. 2, it can be seen that the diffraction peaks of the sample treated at this temperature correspond to those of SiO.sub.2 standard PDF card, and the pre-sintered ceramic block prepared in this example contains a silica crystal phase but does not contain a lithium metasilicate crystal phase.

[0182] The pre-sintered ceramic block was subjected to dry machining using CAD/CAM machining equipment (Roland DWX-51D) to obtain a restoration body.

[0183] The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 880° C. for 8 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a lithium disilicate ceramic restoration.

EXAMPLES 5-10

[0184] The matrix glass powders of Examples 5-10 were prepared and molded according to the method of Example 1 and the components in Table 3.

[0185] The matrix glass body of Examples 5-10 was pre-sintered in a vacuum furnace under a vacuum atmosphere to obtain a pre-sintered ceramic block, wherein the sintering temperature and the holding time were shown in Table 3, and the pressure (absolute pressure) in the vacuum furnace was 3000 Pa; the pre-sintered ceramic blocks of each example were machined using the corresponding CAD/CAM machining equipment in Table 3 to obtain a restoration body. The restoration body of Examples 5-10 was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere to obtain a lithium disilicate glass ceramic restoration, wherein the sintering temperature and holding time were shown in Table 3, and the pressure (absolute pressure) in the vacuum furnace was 3000 Pa.

TABLE-US-00003 TABLE 3 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 SiO.sub.2 64.02%  66.5%  66.8% 70.1% 68.62% 71.17% Li.sub.2O 13.06% 14.05%  14.2% 14.8%  14.9% 15.23% ZrO.sub.2   1.3%  3.91%   0.5% —  1.58% — Al.sub.2O.sub.3  2.05%  1.15%  3.97% 2.15%  2.04%   0.5% K.sub.2O  4.05%  3.48%  3.65% 3.75%   0.5%  1.75% P.sub.2O.sub.5  4.02%  3.85%  3.25% 3.65%  4.95%  2.75% ZnO   3.9%   2.6%   1.6%  1.3%  1.01%   0.1% CeO.sub.2  1.75%  1.55%   0.5%  1.1%  1.31%   2.5% GeO.sub.2  3.98%   1.4%   1.0%  0.5%  2.06%   1.0% La.sub.2O.sub.3   1.2%   0.8%  3.98% 0.73%  0.82%   1.7% MgO — — — —   0.1%  0.18% B.sub.2O.sub.3 — — — — —   0.5% V.sub.2O.sub.5   0.2%  0.15%   0.1% 0.27%  0.32%  0.20% ErO.sub.2  0.17%  0.25%  0.15% 0.15%  0.25%  0.15% Tb.sub.4O.sub.7   0.3%   0.3%   0.2%  0.4%  0.43%  0.27% Pre-sintering 550° C./ 550° C./ 540° C./ 560° C./ 560° C./ 530° C./ temperature/ 60 min 60 min 60 min 60 min 60 min 60 min holding time Dense- 875° C./ 880° C./ 900° C./ 910° C./ 875° C./ 930° C./ sintering 10 min  5 min  3 min  5 min 10 min  1 min temperature/ holding time Machining Roland Roland CEREC CEREC Roland Roland equipment DWX-51D DWX-51D inLab MC inLab MC DWX-51D DWX-51D XL XL

EXAMPLES 11-15

[0186] The matrix glass powders of Examples 11-15 were prepared and molded according to the method of Example 4 and the components in Table 4.

[0187] The matrix glass body of Examples 11-15 was pre-sintered in a vacuum furnace under a vacuum atmosphere to obtain a pre-sintered ceramic block, wherein the sintering temperature and the holding time were shown in Table 4, and the pressure (absolute pressure) in the vacuum furnace was 3000 Pa; the pre-sintered ceramic blocks of each example were machined using the corresponding CAD/CAM machining equipment in Table 3 to obtain a restoration body.

[0188] The restoration body of Examples 11-15 was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere to obtain a lithium disilicate glass ceramic restoration, wherein the sintering temperature and holding time were shown in Table 4, and the pressure (absolute pressure) in the vacuum furnace was 3000 Pa.

TABLE-US-00004 TABLE 4 Example Example Example Example Example 11 12 13 14 15 SiO.sub.2 70.9% 69.14%  71.28%  72.05%  74.59%  Li.sub.2O 14.8% 14.71%  16.82%  15.60%  13.44%  ZrO.sub.2 — 0.79% 0.50% — — Al.sub.2O.sub.3  1.0% 1.09% 1.09% 0.40% 0.99% K.sub.2O 2.95% 4.45% 3.77% 3.91% 4.08% P.sub.2O.sub.5  3.9% 3.26% 3.97% 0.50% 3.33% ZnO  3.5% 3.08% 0.25% 4.91% 2.59% CeO.sub.2 2.15% 0.91% 0.60% 0.30% — GeO.sub.2  0.5% 0.50% 0.30% 0.50% 0.10% La.sub.2O.sub.3 — — — 0.45% — MgO  0.3% 0.60% 0.20% 0.20% B.sub.2O.sub.3 — 0.79% 0.48% 0.40% 0.36% V.sub.2O.sub.5 — 0.15% 0.20% 0.18%  0.1% ErO.sub.2 — 0.15% 0.44%  0.3% 0.07% Tb.sub.4O.sub.7 — 0.38%  0.1% 0.30% 0.35% Pre-sintering 550° C./ 540° C./ 550° C./ 560° C./ 545° C./ temperature/ 60 min 60 min 60 min 60 min 60 min holding time Dense- 875° C./ 850° C./ 890° C./ 875° C./ 875° C./ sintering 15 min 15 min 10 min 15 min 15 min temperature/ holding time Machining CEREC Roland Roland CEREC Roland equipment inLab DWX-51D DWX-51D inLab DWX-51D MC XL MC XL

EXAMPLE 16

[0189] According to the components and amounts of the matrix glass powder 1 in Table 5, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to other components except for colorants (V.sub.2O.sub.5, ErO.sub.2, Tb.sub.4O.sub.7) were ground and mixed uniformly, the mixed matrix raw materials were placed into a platinum crucible that was put into a sintering furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm, followed by adding the colorants and mixing uniformly; to obtain matrix glass powder 1. In the same way, the matrix glass powder 2 and the matrix glass powder 3 were prepared. The obtained three matrix glass powders had the same transmittance but different color.

[0190] The matrix glass powder 1 was added into a dry pressing mould, the upper surface of the powder was flattened to be flat, then the matrix glass powder 2 was added, the upper surface of the powder was flattened to be flat, and then the matrix glass powder 3 was added, wherein the matrix glass powder 1 has a thickness of 5.5 mm, the matrix glass powder 2 has a thickness of 5 mm, and the matrix glass powder 3 has a thickness of 5.5 mm; uniaxial dry pressing molding was carried out under a pressure of 50 MPa, and then a matrix glass body with a weight of about 9-10 g was obtained.

[0191] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 555° C. for 60 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block;

[0192] The pre-sintered ceramic block was subjected to wet machining using CAD/CAM machining equipment (CEREC inLab MC XL, SIRONASIRONA) to obtain a restoration body. The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 920° C. for 5 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a three-layer colored lithium disilicate ceramic restoration.

TABLE-US-00005 TABLE 5 Matrix glass Matrix glass Matrix glass Component powder 1 powder 2 powder 3 SiO.sub.2 68.96%  68.965%   68.96%  Li.sub.2O 15.22%  15.22%  15.22%  ZrO.sub.2 1.67% 1.67% 1.67% Al.sub.2O.sub.3 1.00% 1.00% 1.00% K.sub.2O 3.68% 3.68% 3.68% P.sub.2O.sub.5 3 63% 3.63% 3.63% ZnO 2.69% 2.69% 2.69% CeO.sub.2 1.58% 1.58% 1.58% GeO.sub.2 0.77% 0.77% 0.77% La.sub.2O.sub.3 0.30% 0.30% 0.30% V.sub.2O.sub.5 0.11% 0.09% 0.07% ErO.sub.2 0.09% 0.08% 0.07% Tb.sub.4O.sub.7 0.30% 0.33% 0.36%

EXAMPLE 17

[0193] According to the components and amounts of the matrix glass powder 1 in Table 6, the matrix raw materials such as oxides, carbonate compounds, and phosphates compound corresponding to other components except for colorants were ground and mixed uniformly, the mixed raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm, followed by adding the colorants and mixing uniformly; to obtain matrix glass powder 1. In the same way, the matrix glass powder 2 and the matrix glass powder 3 were prepared. The obtained three matrix glass powders were different in transmittance and color.

[0194] The matrix glass powder 1 was added into a dry pressing mould, the upper surface of the powder was flattened to be flat, then the matrix glass powder 2 was added, the upper surface of the powder was flattened to be flat, and then the matrix glass powder 3 was added, wherein the matrix glass powder 1 has a thickness of 5.7 mm, the matrix glass powder 2 has a thickness of 4.9 mm, and the matrix glass powder 3 has a thickness of 5.4 mm; uniaxial dry pressing molding was carried out under a pressure of 50 MPa, and then a matrix glass body with a weight of about 9-10 g was obtained.

[0195] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 560° C. for 120 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block; the pre-sintered ceramic block was subjected to XRD detection, the result was shown in FIG. 3, the diffraction peaks of the sample treated at this temperature correspond to those of SiO.sub.2 standard PDF card, and the pre-sintered ceramic block prepared in this example contains a silica crystal phase but does not contain a lithium metasilicate crystal phase.

[0196] The pre-sintered ceramic block was subjected to dry machining using CAD/CAM machining equipment (Roland DWX-51D) to obtain a restoration body.

[0197] The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 875° C. for 15 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a three-layered lithium disilicate glass ceramic restoration with gradual transmittance and color.

TABLE-US-00006 TABLE 6 Compo- Matrix glass Matrix glass Matrix glass nent powder 1 powder 2 powder 3 SiO.sub.2 68.96%  69.41%  69.94%  Li.sub.2O 15.22%  14.58%  14.28%  ZrO.sub.2 1.51% 1.49% 1.19% Al.sub.2O.sub.3 1.00% 1.24% 1.00% K.sub.2O 3.73% 3.18% 3.78% P.sub.2O.sub.5 3.63% 3.88% 4.00% ZnO 1.69% 3.00% 2.89% CeO.sub.2 1.58% 1.17% 1.10% GeO.sub.2 0.77% 0.75% 0.62% La.sub.2O.sub.3 0.40% 0.70% 0.70% V.sub.2O.sub.5 0.11% 0.09% 0.07% ErO.sub.2 0.09% 0.08% 0.07% Tb.sub.4O.sub.7 0.26% 0.30% 0.36% MnO.sub.2 0.04% 0.03% —

EXAMPLE 18

[0198] According to the components and amounts of the matrix glass powder 18-1 in Table 7, the matrix raw materials such as oxides, carbonate compounds, and phosphates corresponding to other components except for colorants were ground and mixed uniformly, the mixed raw materials were placed into a platinum crucible that was put into a furnace, heating to 1550° C., holding for 1 h, and clarifying and homogenizing to obtain a matrix molten glass; water-quenching was carried out on the prepared matrix molten glass to obtain glass fragments, and the glass fragments were dried for 1 h at 120° C.; and the dried glass fragments were ground to an average particle size of 5-30 μm, followed by adding the colorants and mixing uniformly; to obtain monochromatic matrix glass powder 18-1. In the same way, monochromatic matrix glass powder 18-2 and monochromatic matrix glass powder 18-3 were prepared. They are mixed uniformly according to a ratio of monochromatic matrix glass powder 18-1: monochromatic matrix glass powder 18-2: monochromatic matrix glass powder 18-3=2:4:3 to obtain matrix glass powder 18-L.

[0199] According to the components and amounts of each matrix glass powder in Table 8, monochromatic matrix glass powder 18-4, monochromatic matrix glass powder 18-5, and monochromatic matrix glass powder 18-6 were prepared respectively according to the preparation method of monochromatic matrix glass powder 18-1. They are mixed uniformly according to a ratio of monochromatic matrix glass powder 18-4: monochromatic matrix glass powder 18-5: the monochromatic matrix glass powder 18-6=2.5:3.5:3 to obtain matrix glass powder 18-M.

[0200] According to the components and amounts of each matrix glass powder in Table 9, monochromatic matrix glass powder 18-7, monochromatic matrix glass powder 18-8, and monochromatic matrix glass powder 18-9 were prepared respectively according to the preparation method of monochromatic matrix glass powder 18-1. They are mixed uniformly according to a ratio of monochromatic matrix glass powder 18-7: monochromatic matrix glass powder 18-8: the monochromatic matrix glass powder 18-9=2:3.5:3.5 to obtain matrix glass powder 18-H.

[0201] Some of matrix glass powder 18-L and some of matrix glass powder 18-M were mixed according to a mass ratio of 1:1.5 to obtain glass powder 18-LM;

[0202] Some of matrix glass powder 18-M and some of matrix glass powder 18-H were mixed according to a mass ratio of 1:2 to obtain glass powder 18-MH;

[0203] The matrix glass powder L was added into a dry pressing mould, the upper surface of the powder was flattened to be flat, then the matrix glass powder LM was added, the upper surface of the powder was flattened to be flat, and then the matrix glass powder M was added, the upper surface of the powder was flattened to be flat, then the matrix glass powder MH was added, the upper surface of the powder was flattened to be flat, then the matrix glass powder H was added, wherein the matrix glass powder L has a thickness of 4 mm, the matrix glass powder LM has a thickness of 3 mm, the matrix glass powder M has a thickness of 2.5 mm, the matrix glass powder MH has a thickness of 2.5 mm, and the matrix glass powder H has a thickness of 4 mm; uniaxial dry pressing molding was carried out under a pressure of 75 MPa, and then a matrix glass body with a weight of about 9-10 g was obtained.

[0204] The matrix glass body was sintered in a vacuum furnace under a vacuum atmosphere at 550° C. for 60 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a pre-sintered ceramic block;

[0205] The pre-sintered ceramic block was subjected to dry machining using CAD/CAM machining equipment (Roland DWX-51D) to obtain a restoration body.

[0206] The restoration body was subjected to dense-sintering in a sintering furnace under a vacuum atmosphere at 875° C. for 10 min, with a pressure (absolute pressure) in the vacuum furnace of 3000 Pa, to obtain a five-layered lithium disilicate glass ceramic restoration with gradual transmittance and color.

TABLE-US-00007 TABLE 7 Compo- Matrix glass Matrix glass Matrix glass nent powder 18-1 powder 18-2 powder 18-3 SiO.sub.2 69.06%  69.06%  69.06%  Li.sub.2O 15.15%  15.25%  15.25%  ZrO.sub.2 1.52% 1.52% 1.52% Al.sub.2O.sub.3 1.01% 1.01% 1.01% K.sub.2O 3.73% 3.73% 3.73% P.sub.2O.sub.5 3.64% 3.64% 3.64% ZnO 2.69% 2.69% 2.69% CeO.sub.2 1.58% 1.58% 1.58% GeO.sub.2 0.77% 0.77% 0.77% La.sub.2O.sub.3 0.40% 0.40% 0.40% V.sub.2O.sub.5 — —  0.3% ErO.sub.2 — 0.35% — Tb.sub.4O.sub.7 0.15% — 0.05% MnO.sub.2 0.20% — —

TABLE-US-00008 TABLE 8 Compo- Matrix glass Matrix glass Matrix glass nent powder 18-4 powder 18-5 powder 18-6 SiO.sub.2 69.54%  69.54%  69.54%  Li.sub.2O 14.61%  14.61%  14.61%  ZrO.sub.2 1.50% 1.50% 1.50% Al.sub.2O.sub.3 1.25% 1.25% 1.25% K.sub.2O 3.28% 3.28% 3.28% P.sub.2O.sub.5 3.89% 3.89% 3.89% ZnO 3.01% 3.01% 3.01% CeO.sub.2 1.18% 1.18% 1.18% GeO.sub.2 0.75% 0.75% 0.75% La.sub.2O.sub.3 0.70% 0.70% 0.70% V.sub.2O.sub.5 — — 0.24% ErO.sub.2 — 0.29% — Tb.sub.4O.sub.7 0.15% — 0.05% MnO.sub.2 0.14% — —

TABLE-US-00009 TABLE 9 Compo- Matrix glass Matrix glass Matrix glass nent powder 18-7 powder 18-8 powder 18-9 SiO.sub.2 70.29%  70.29%  70.29%  Li.sub.2O 14.35%  14.35%  14.35%  ZrO.sub.2  1.2%  1.2%  1.2% Al.sub.2O.sub.3 1.01% 1.01% 1.01% K.sub.2O 3.75% 3.75% 3.75% P.sub.2O.sub.5 4.02% 4.02% 4.02% ZnO 2.85% 2.85% 2.85% CeO.sub.2 1.11% 1.11% 1.11% GeO.sub.2 0.62% 0.62% 0.62% La.sub.2O.sub.3  0.7%  0.7%  0.7% V.sub.2O.sub.5 — —  0.1% ErO.sub.2 —  0.1% — Tb.sub.4O.sub.7 0.05% — — MnO.sub.2 0.05% — —

[0207] In the above Tables 1-9, the percentages of each component are mass percentages. XRD detection conditions for Examples 1-18 were as follows: the samples were detected using X-ray diffraction (XRD) with a D8 Advance X-ray diffractometer obtained by Bruker, Karlsruhe, Germany, wherein a radiation source is Cu target, an applied voltage is 40.0 kV, an anode current is 40.0 mA, a slit width is 1.0 mm, and a scanning range is 10°-80°.

Performance Test

[0208] Vickers hardness and three-point bending strength of the pre-sintered ceramic blocks, and three-point bending strength and visible light transmittance of the pre-sintered ceramic blocks subjected to dense-sintering in Examples 1-18 were tested respectively, and the test results were shown in Table 10; wherein,

[0209] (1) Vickers hardness was measured using a HVS-50 Vickers hardness tester according to the method described in ISO 14705:2016 and calculated according to the following formula:

[00001]$\mathrm{HV}=0.001854\frac{F}{d^2}$

wherein:
HV—Vickers hardness, in GPa
F—Load on the pressure head (N)
d—Arithmetic average of two diagonal lines of indentation (mm)

[0210] (2) Three-point bending strength was measured according to the method described in ISO 14704:2016 and calculated according to the following formula:

[00002]${\sigma }_f=\frac{3\mathrm{Fa}}{2{\mathrm{bd}}^2}$

wherein:
σ.sub.f—Flexural strength, in MPa
F—Breaking load, in N
a—Span, in mm
b—Width of test sample, in mm
d—Thickness of test sample, in mm

[0211] (3) The visible light transmittance was measured according to the method described in ISO 9050: 2003, and the visible light transmittance was calculated according to the following formula:

[00003]${\tau }_v=\frac{\underset{\lambda =380\mathrm{nm}}{\overset{780\mathrm{nm}}{.Math.}}\tau \left(\lambda \right)D_{\lambda }V\left(\lambda \right)\mathrm{\Delta \lambda }}{\underset{\lambda =380\mathrm{nm}}{\overset{780\mathrm{nm}}{.Math.}}{D}_{\lambda }V\left(\lambda \right)\mathrm{\Delta \lambda }}$

wherein:

[0212] τ.sub.v—Visible light transmittance of the sample, %;

[0213] τ(λ)—Visible spectral transmittance of the sample, %

[0214] D.sub.λ—Relative spectral power distribution of standard illuminant D.sub.65

[0215] V(λ)—Photopic vision spectral luminous efficiency

[0216] Δλ—Wavelength interval

TABLE-US-00010 TABLE 10 Strength of pre- Strength sintered after Vickers ceramic dense- hardness block sintering Visible light (Gpa) (MPa) (MPa) transmittance Example 1 1.84 41.17 354.04 45.23% Example 2 2.09 63.39 310.72 54.56% Example 3 2.12 55.93 330.29 55.49% Example 4 1.71 40.03 373.47 46.68% Example 5 1.65 40.70 340.79 57.01% Example 6 1.76 51.43 342.34 47.12% Example 7 1.56 37.66 353.1 45.90% Example 8 1.99 49.22 377.52 45.95% Example 9 1.92 55.38 360.6 44.27% Example 10 1.39 36.89 339.05 41.05% Example 11 1.87 39.63 397.75 55.98% Example 12 1.60 40.60 355.32 43.44% Example 13 1.80 46.14 369.49  42.9% Example 14 1.91 46.57 359.07 38.25% Example 15 1.80 41.06 338.66 46.49% Example 16 2.05 47.52 355.60 42.74% Example 17 1.89 50.94 376.08 Mpa 43.08%-47.92%- 54.20% (gradual) Example 18 1.72 47.90 344.83 Mpa 43.11%-45.01%- 47.39%-50.83%- 54.44% (gradual)
Note: the strength in the table refers to the three point bending strength

[0217] The foregoing descriptions are merely preferred embodiments of this application, but are not intended to limit this application. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of this application shall fall within the protection scope of this application.