JPH10323354A - Dental crystallized ceramic frame core and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material with excellent properties of high hardness, bending strength, and fracture toughness, by depositing crystal in glass impregnated into a porous ceramic material. SOLUTION: This dental ceramic frame core comprises a porous ceramic material and a crystallized glass impregnated part. The porous ceramic material is obtained by sintering a raw material containing either of alumina, zirconia, or spinel as the main component, and can contain noble metal powder of gold, platinum, or an alloy, etc. On the other hand, the crystallized glass impregnated part is made deposit crystal in impregnated glass impregnated in the porous ceramic material. A part or a whole of the crystal glass impregnated part can be made into crystallized glass. Leucite depositing high swelling crystallized glass, etc., are preferable for the crystallized glass. Further, when leucite crystal is deposited in impregnated glass, strength, hardness, and toughness can be further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dental porcelain frame core and a method for producing the same. An all-ceramic crown can be manufactured by laying porcelain on a dental porcelain frame core.

[0002]

2. Description of the Related Art At present, from the viewpoint of color tone, all-ceramic crowns having no metal lining are receiving attention.
Known methods of its production include dispersion strengthening of glass, partial crystallization of glass, and a method of forming a stress surface layer in porcelain by ion exchange. Only it was difficult to make.

In order to solve the above problem, a lanthanum oxide-based glass (La ₂ O ₃ -B ₂ O ₃ -Al ₂ O _{3) is used} for porous ceramics such as a porous alumina sintered body formed by the present inventors.
Dental porcelain frame core and a method for manufacturing method comprising impregnating the glass -SiO _2, etc.) are known. For example, JP-A-5-58835, JP-A-5-186
No. 310, JP-A-6-285091 and JP-A-7-16246.

According to the above method, a bending strength of about 40.0 k
gf / mm ² (392.4 N / mm ² ), fracture toughness of about 2
A glass-impregnated porcelain frame core having a strength characteristic up to about 0.0 kgf / mm ^3/2 (196.2 N / mm ^3/2 ) can be manufactured.

[0005]

However, an all-ceramic crown made by laying porcelain on a conventional glass-impregnated porcelain frame core has a flexural strength of about 6.2.
kgf / mm ² (60.8 N / mm ² ), fracture toughness 3.7
kgf / mm ^3/2 (36.3 N / mm ^3/2 ), and the strength properties are still insufficient. The reason is considered as follows.

That is, the all-ceramic crown is obtained by laying porcelain on a glass-impregnated porcelain frame core, and the thickness of the frame core is compared with the thickness of the porcelain laid on the frame core. Therefore, it is considered that the strength of the all-ceramic crown depends on the strength characteristics of the porcelain laid on the frame core because it is about 1/3 times thinner.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a dental porcelain frame core having higher strength characteristics and a method of manufacturing the same.

[0008]

SUMMARY OF THE INVENTION The present inventor has made it possible to produce a dental porcelain frame core having higher strength characteristics by precipitating crystals in an impregnated glass impregnated in a porous ceramic material. They found that they could do it, and completed the present invention. According to the present invention, the above object can be achieved by the following method for manufacturing a dental porcelain frame core and a dental porcelain frame core.

That is, it is a dental porcelain frame core composed of a porous ceramic material and crystallized glass. Further, the present invention is a dental porcelain frame core having a porous ceramic material and a crystallized glass impregnated portion containing a crystallized glass and impregnating the porous ceramic material.

Preferably, a dental porcelain frame core having the following configuration is provided. The above-mentioned dental porcelain frame core, wherein the crystallized glass is a leucite-deposited high expansion crystallized glass. The above dental porcelain frame core, wherein the crystallized glass is β-eucryptite precipitated low expansion crystallized glass or β-spodumene precipitated low expansion crystallized glass.

Further, the present invention relates to a method for manufacturing a dental porcelain frame core having a crystallization step of precipitating a crystal on an impregnated glass impregnated with a porous ceramic material. Preferably,
The method for producing a dental porcelain frame core described above, wherein at least one of a leucite crystal, a β-eucryptite crystal, and a β-spodumene crystal is precipitated in the crystallization step.

In the present invention, the description of the numerical range is as follows:
It shall include not only the end values but also any arbitrary intermediate values contained therein.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

[Dental porcelain frame core] The dental porcelain frame core of the present invention preferably comprises a porous ceramic material and a crystallized glass impregnated portion.

(Porous Ceramic Material) The porous ceramic material preferably contains alumina, zirconia or spinel as a main component. The porous ceramic material may contain a noble metal powder such as gold, platinum, silver, palladium or an alloy thereof. The ratio of porosity (porosity) in the porous ceramic material is preferably 15 to 35% by volume, more preferably 20 to 25% by volume. The maximum pore diameter of the pores in the porous ceramic material is preferably 1 to 5 μm (more preferably 1 to 2 μm).
m), and the average pore diameter of the pores is 0.1 to 0.5 μm (more preferably 0.15 to 0.3 μm).

(Crystalized Glass Impregnated Portion) The crystallized glass impregnated portion impregnates a porous ceramic material and contains crystallized glass. The crystallized glass impregnated part can be partially or entirely made of crystallized glass, and in addition to crystallized glass, a color tone adjusting oxide and glass other than crystallized glass (for example, non-crystallized glass or hardly crystallized glass) Glass).

As the color tone adjusting oxide, MnO ₂ , Fe ₂
There are O ₃ and CeO ₂ . MnO ₂ from brown to purple, F
e ₂ O ₃ can be arbitrarily colored to a color tone of red and CeO ₂ can be colored to yellow or brown. In addition, CeO ₂ is also effective in preventing a change in color tone over time due to sunlight irradiation. The content of crystals in the crystallized glass-impregnated portion is preferably 20 to 95% by weight, more preferably 30 to 80% by weight.

(Crystallized glass) A crystallized glass is a crystal obtained by reheating glass and a glass (matrix).
This is an inorganic material having excellent features that cannot be obtained with ordinary glass. Examples of the crystal, for example, leucite _{(K 2 O · Al 2 O} 3 · 4SiO 2), β
-Eucryptite (Li ₂ O.Al ₂ O ₃ .2Si
O ₂ ), β-spodumene (Li ₂ O.Al ₂ O ₃ .4S)
iO ₂ ), quartz (SiO ₂ ), lithium metasilicate (Li ₂
O.SiO ₂ ), lithium disilicate (Li ₂ O.2Si)
O ₂ ), rutile (TiO ₂ ), cordierite (2MgO
.2Al ₂ O ₃ .5SiO ₂ ), Garnite (ZnO.A)
l ₂ O _3), willemite is (2ZnO · SiO _2), fluorine phlogopite _{(NaMg 3 (Si 3 AlO 10} ) F 2) or the like.

The crystallized glass is preferably leucite precipitated high expansion crystallized glass, β-eucryptite precipitated low expansion crystallized glass or β-spodumene precipitated low expansion crystallized glass. Further, a low expansion crystallized glass in which both β-eucryptite and β-spodumene are precipitated can be obtained.

The crystal content in the crystallized glass can be preferably 20 to 95% by weight (more preferably 30 to 80% by weight). The crystal grain size in the crystallized glass is not particularly limited, but is preferably small from the viewpoint of strength.

[Method of Manufacturing Dental Porcelain Frame Core] The method of manufacturing the dental porcelain frame core of the present invention is characterized by having a crystallization step. (Crystallization Step) The crystallization step is a step of depositing crystals on the impregnated glass impregnated in the porous ceramic material. Normally, crystals can be generated in the impregnated glass by maintaining the crystallization temperature according to the composition of the impregnated glass for a predetermined time.

Preferably, as the impregnated glass impregnated in the porous ceramic material, leucite crystals (K ₂ O · A
l ₂ O ₃ .4SiO ₂ ), β-eucryptite crystals (L
_{i 2 O · Al 2 O 3} · 2SiO 2) and β- spodumene crystal _{(Li 2 O · Al 2 O} 3 · 4SiO 2) a glass composition range capable of precipitating one or more of.

As a glass on which leucite crystals can be precipitated, glass containing SiO ₂ , Al ₂ O ₃ and K ₂ O as main components is preferable.
_It may contain one or more of ₂ O, Na ₂ O, MgO, and CaO. The preferred content ratio by weight of each component in 100 parts by weight of glass capable of precipitating leucite crystals is 50 to 82 parts by weight (more preferably 65 to 75 parts by weight) for SiO _{2 and} 5 to 15 parts by weight for Al ₂ O _3. Parts by weight (preferably 7 to 12 parts by weight), K ₂ O is 1 to 15 parts by weight (preferably 2 to 10 parts by weight, more preferably 4 to 8 parts by weight).
Parts by weight), 0 to 15 parts by weight of Na ₂ O (more preferably 12 parts by weight or less, further preferably 8 to 11 parts by weight),
Li ₂ O, each of MgO and CaO is 0-5 parts by weight respectively. Such a glass is harmless and highly safe, and thus is preferable as a material for manufacturing a dental porcelain frame core.

Glasses from which β-eucryptite crystals can be precipitated include SiO ₂ , Al ₂ O ₃ and L
Glass containing i ₂ O as a main component is preferable, and a glass containing at least one of Na ₂ O, K ₂ O, MgO, and CaO in addition to these main components may be used. The preferred content ratio by weight of each component in 100 parts by weight of glass capable of precipitating β- eucryptite crystals, SiO ₂ is 50-7
5 parts by weight (more preferably 55 to 70 parts by weight), Al ₂
O ₃ is 5 to 15 parts by weight (preferably 7 to 12 parts by weight),
Li ₂ O is 5 to 15 parts by weight (preferably 7 to 15 parts by weight, more preferably 8 to 15 parts by weight), and Na ₂ O is 0 to 5 parts by weight.
6 parts by weight (more preferably 5 parts by weight or less, more preferably 2 to 4 parts by weight), K ₂ O 0 to 10 parts by weight (more preferably 8 parts by weight or less, more preferably 2 to 6 parts by weight), Each of MgO and CaO is 0 to 5 parts by weight. Such a glass is harmless and highly safe, and thus is preferable as a material for manufacturing a dental porcelain frame core.

Glasses on which β-spodumene crystals can be deposited include SiO ₂ , Al ₂ O ₃ and Li ₂
A glass containing O as a main component is preferable, and a glass containing at least one of Na ₂ O, K ₂ O, MgO, and CaO in addition to these main components may be used. The preferred content ratio of each component in 100 parts by weight of glass capable of precipitating β-spodumene crystals is 50 to 82 parts by weight (more preferably 65 to 77 parts by weight) of SiO _{2 and} 5 to 5 parts by weight of Al ₂ O _3.
To 20 parts by weight (preferably 7 to 15 parts by weight), Li ₂ O
There 4-16 parts by weight (preferably 5 to 16 parts by weight, more preferably 6 to 16 parts by weight), Na ₂ O 0 to 5 parts by weight (more preferably 0.1 to 3 parts by weight, more preferably 0 0.2 to ₂ parts by weight), K2O is 0 to 10 parts by weight (more preferably 8 parts by weight or less, more preferably 2 to 6 parts by weight), and each of MgO and CaO is 0 to 5 parts by weight. . Such a glass is harmless and highly safe, and thus is preferable as a material for manufacturing a dental porcelain frame core.

The crystallization of the impregnated glass is preferably 700
An arbitrary amount of crystals according to the holding time can be precipitated by a heat treatment of holding at a temperature of 1 to 1100 ° C (more preferably 800 to 1000 ° C, further preferably 850 to 950 ° C) for a certain period of time. Then, preferably, at least one crystal of leucite, β-eucryptite and β-spodumene is precipitated in the impregnated glass. By precipitating such crystals, each of the strength, hardness and toughness can be further increased.

In the method for manufacturing a dental porcelain frame core of the present invention, a step of forming a porous ceramic material and a step of impregnating glass may be provided before the crystallization step.

(Porous Ceramic Material Forming Step) In the porous ceramic material forming step, a ceramic raw material powder containing alumina (preferably spherical alumina), zirconia or spinel as a main component is molded to obtain a molded body. This is a step of sintering the formed body by primary firing to obtain a porous ceramic material (sintered body).

The ceramic raw material powder preferably has an average particle size of 1 to 5 μm, more preferably 8 to 35% by weight of fine particles having a particle size of 1 μm or less and other particles having a particle size of 1 μm. Use powder that exceeds Ceramic powders include metal powders, preferably gold, platinum, silver,
A noble metal powder such as palladium or an alloy thereof can be added. The average particle size of the metal powder is preferably set to 0.1 to 2 μm. The addition amount of the metal powder,
It is preferably 0.01 to 1 part by weight based on 100 parts by weight of the ceramic raw material powder.

As a method of forming a ceramic raw material powder (or a ceramic raw material powder and a metal powder) to obtain a molded body, for example, a condensing method in which a ceramic raw material powder is dissolved in water, laid on a model, and then condensed, a slip casting method Alternatively, a brush molding method or the like can be used. The firing temperature of the primary firing is preferably 1100 to 1100.
Bring to 1250 ° C. The holding time at the firing temperature is preferably 10 minutes to 4 hours. Further, the temperature raising time from normal temperature to the firing temperature is, for example, 20 minutes to 2 minutes.
Can be time.

(Glass Impregnation Step) The glass impregnation step is a step of impregnating a porous ceramic material with glass. As the porous ceramic material, those obtained in the porous ceramic material forming step can be used. In the glass impregnation process,
The glass is placed on the porous ceramic material, and preferably a temperature slightly lower than the primary firing temperature for forming the porous ceramic material (more preferably a temperature of 1000 to 1200 ° C. and a temperature lower than the primary firing temperature) The porous ceramic material is impregnated with the molten glass by holding at 4 to 8 hours at a slightly lower temperature to obtain a porous ceramic material impregnated with the molten glass.

As the glass to be impregnated in the porous ceramic material, glass capable of precipitating crystals is used. To the impregnating glass, a color tone adjusting oxide or a glass in which crystals are difficult to precipitate can be added.

After the porous ceramic material is impregnated with the molten glass, the molten glass can be kept at the crystallization temperature of the glass to precipitate crystals. A surplus glass removing step of removing the used surplus glass by sandblasting or the like can be provided.

[0033]

【Example】

[Example 1] A ceramic raw material powder whose main component is alumina and has a spherical shape (the content of ceramic particles having a particle size of 1 µm or less is 21% by weight, and the content of ceramic particles having a particle size of 1 µm or less is 79%) The temperature was raised to 1120 ° C. in 2 hours, and the temperature was maintained for 1 hour to fire a sample formed of a porous ceramic layer. Further, 11
The temperature was kept at 00 ° C. for 4 hours to impregnate the porous ceramic layer with glass.

The composition of the impregnating glass is SiO ₂ 7
2.0 parts by weight, 9.5 parts by weight of Al ₂ O ₃ , Na ₂ O 1
0.0 parts by weight, 6.0 parts by weight of K ₂ O, and other components such as lithium oxide, magnesium oxide, and calcium oxide. In addition, Fe ₂ O ₃ was added to the glass for impregnation as a color adjusting oxide. After impregnating the porous ceramic layer with the impregnating glass or the like, a temperature of 900
Heat treatment was performed at a temperature of 1 ° C. for 1 hour to precipitate leucite crystals in the impregnated glass. Thereby, further strength, hardness and toughness were enhanced.

A porcelain material having the composition shown in Table 1 is applied to the upper surface of the porous ceramic layer impregnated with the impregnating glass or the like, and is built up to a thickness about twice that of the core portion. The temperature was raised for 30 minutes, and then held and fired for 10 minutes. Then, an all-ceramic crown was obtained. The porcelain of Examples 4 and 5 described below also had the same composition as the porcelain of Example 1.

[0036]

[Table 1]

Example 2 A spherical ceramic raw material powder whose main component is alumina (the content of ceramic particles having a particle diameter of 1 μm or less is 21% by weight and the particle diameter is 1%)
The content of ceramic particles exceeding μm is 79% by weight. ), The temperature was raised to 1120 ° C. in 2 hours, and the temperature was maintained for 1 hour to fire the sample formed of the porous ceramic layer.
Further, the temperature was kept at 1100 ° C. for 4 hours, and the porous ceramic layer was impregnated with glass. As the impregnating glass, a glass having a composition of SiO ₂ —Al ₂ O ₃ —K ₂ O—Li ₂ O was used. Note that CeO ₂ was added to the glass for impregnation as a color tone adjusting oxide.

Thereafter, heat treatment was performed at 900 ° C. for 4 hours to crystallize β-eucryptite in the impregnated glass. Thereby, the strength, hardness, and toughness were further improved. The porcelain shown in Table 1 was laid and fired on the porous ceramic layer impregnated with the impregnating glass and the like in the same manner as in Example 1 to obtain an all-ceramic crown.

Example 3 A spherical ceramic raw material powder whose main component is alumina (the content of ceramic particles having a particle size of 1 μm or less is 21% by weight and the particle size is 1%)
The content of ceramic particles exceeding μm is 79% by weight. ), The temperature was raised to 1120 ° C. in 2 hours, and the temperature was maintained for 1 hour to fire the sample formed of the porous ceramic layer.
Further, the temperature was kept at 1100 ° C. for 4 hours, and the porous ceramic layer was impregnated with glass.

As the impregnating glass, the composition SiO ₂ -A
using _{l 2 O 3 -K 2 O-} Li 2 O system glass. Note that MnO ₂ was added to the glass for impregnation as a color tone adjusting oxide. Thereafter, heat treatment was performed at a temperature of 900 ° C. for 6 hours to precipitate and crystallize β-spodumene in the impregnated glass. Thereby, the strength, hardness, and toughness were further improved. The porcelain shown in Table 1 was laid and fired on the porous ceramic layer impregnated with the impregnating glass and the like in the same manner as in Example 1 to obtain an all-ceramic crown.

Example 4 Ceramic raw material powder whose main component is zirconia (the content of ceramic particles having a particle size of 1 μm or less is 15% by weight, and the content of ceramic particles having a particle size of 1 μm or more is 85% by weight. 1)
The temperature was raised to 120 ° C. in 2 hours, and the temperature was maintained for 1 hour to fire the sample formed of the porous ceramic layer. Further, 1100 ° C
, And the porous ceramic layer was impregnated with glass. The composition of the impregnating glass is SiO ₂ 7
2.0 parts by weight, 9.5 parts by weight of Al ₂ O ₃ , Na ₂ O 1
0.0 parts by weight, 6.0 parts by weight of K ₂ O, and other components such as lithium oxide, magnesium oxide, and calcium oxide. In addition, Fe ₂ O ₃ was added to the glass for impregnation as a color adjusting oxide.

Thereafter, a heat treatment was performed at a temperature of 900 ° C. for 1 hour to precipitate leucite crystals in the impregnated glass. Further, the strength, hardness and toughness were further improved.
Porcelain having the composition shown in Table 1 was laid and fired on the porous ceramic layer impregnated with the glass for impregnation in the same manner as in Example 1 to obtain an all-ceramic crown.

Examples 5 to 7 A porous ceramic layer impregnated with glass or the like was obtained in the same manner as in Example 1 except that the glass to be impregnated and the color tone adjusting oxide were as shown in Table 3. After impregnating the porous ceramic layer with the impregnating glass or the like, in Example 5, heat treatment was performed at 900 ° C. for 1 hour to precipitate leucite crystals in the impregnated glass. In Examples 6 and 7, heat treatment was performed at 900 ° C. for 5 hours to precipitate β-eucryptite and β-spodumene crystals in the impregnated glass.
Thereby, further strength, hardness and toughness were enhanced. Porcelain having the composition shown in Table 1 was laid and fired on the porous ceramic layer impregnated with the glass for impregnation in the same manner as in Example 1 to obtain an all-ceramic crown. Table 2 summarizes the materials of the porous ceramic layers, the precipitated crystals in the impregnated glass, and the heat treatment conditions (temperature (° C.) and holding time (hour)) in Examples 1 to 7.

[0044]

[Table 2]

Comparative Example 1 A ceramic raw material powder having a main component of alumina and having a spherical shape (the content of ceramic particles having a particle size of 1 μm or less is 21% by weight,
The content of ceramic particles exceeding μm is 79% by weight. ), The temperature was raised to 1120 ° C. in 2 hours, and the temperature was maintained for 1 hour to fire the sample formed of the porous ceramic layer. Further, the temperature was kept at 1100 ° C. for 4 hours, and the porous ceramic layer was impregnated with glass. The composition of this impregnating glass is lanthanum oxide glass (La ₂ O ₃ 45 parts by weight-B ₂
O ₃ 45 parts by weight—Al ₂ O ₃ 15 parts by weight—SiO ₂ 13 parts by weight).

A porcelain material having the composition shown in Table 1 was laid and fired on the porous ceramic layer impregnated with the glass for impregnation in the same manner as in Example 1 to obtain an all-ceramic crown.

The content ratio (weight) of each component of the impregnating glass used in Examples 1 to 7 and Comparative Example 1 (each component of the impregnating glass and the color tone adjusting oxide when the color adjusting oxide is added). Ratio), the hardness, bending strength and fracture toughness of the porous ceramic layer impregnated with the glass and the like, and the bending strength of the all-ceramic crown composed of the porous ceramic layer impregnated with the glass and the like and laid with porcelain and fired Table 3 shows the fracture toughness.

[0048]

[Table 3]

(Characteristic evaluation method) The evaluation method of hardness, bending strength and fracture toughness is as follows. Hardness: Depends on Vickers hardness. Bending strength test: Based on a three-point bending test. Fracture toughness test: by the IF method. -Equipment used: Vickers hardness tester DVK-1 manufactured by Matsuzawa Seiki-Test conditions: temperature-normal temperature Load-20 kgf Load application speed-70 m / s Holding time-15 seconds Number of indentations-5 / sample

Calculation method of test results K _c = (0.073 × P) ÷ C ^1.5 K _c : fracture toughness value (kgf / mm ^3/2 ) P: load (kgf) c: half length of crack (mm) The measurement of 2c was performed 10 minutes after indentation.

[0051]

The dental porcelain frame core of claim 1 is
Since the dental porcelain frame core according to claim 2 is composed of the porous ceramic material and the crystallized glass, the dental ceramic frame core contains the crystallized glass while impregnating the porous ceramic material. The presence of the crystallized glass impregnated portion provides the following basic effects. Has high strength properties. In particular, it has excellent strength properties, such as high hardness, bending strength and fracture toughness. Therefore, an all-ceramic crown having high strength characteristics can be manufactured. Since each of the dental porcelain frame cores according to claims 3 and 4 further has the specific components, the above-described basic effects are remarkable and have higher strength characteristics. All ceramic crowns can be manufactured.

The method for manufacturing a dental porcelain frame core according to claims 5 to 6 has a crystallization step of depositing crystals on impregnated glass impregnated with a porous ceramic material. The basic effect is that the frame core can be easily manufactured. Since the method for manufacturing a dental porcelain frame core according to claim 6 further includes the specific components, the above-described basic effects are remarkable,
A dental porcelain frame core having higher strength properties can be manufactured.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Otsuka 3-36, Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Pref. No. 36 Noritake Company Limited

Claims (6)

[Claims] 1. A dental porcelain frame core comprising a porous ceramic material and crystallized glass. 2. A dental porcelain frame core comprising: a porous ceramic material; and a crystallized glass impregnated portion that impregnates the porous ceramic material and contains crystallized glass. 3. The dental porcelain frame core according to claim 1, wherein the crystallized glass is leucite-precipitated high expansion crystallized glass. 4. The crystallized glass according to claim 1, wherein the glass is β-eucryptite precipitated low expansion crystallized glass or β-spodumene precipitated low expansion crystallized glass.
A dental porcelain frame core according to any one of the above. 5. A method for manufacturing a dental porcelain frame core, comprising a crystallization step of precipitating a crystal on an impregnated glass impregnated in a porous ceramic material. 6. The dental porcelain according to claim 5, wherein in the crystallization step, at least one of leucite crystal, β-eucryptite crystal and β-spodumene crystal is precipitated. Manufacturing method of frame core.