JPH05186310A - Dental ceramic material frame and its production - Google Patents

Abstract

PURPOSE:To obtain a dental ceramic material frame capable of producing an all ceramic crown having excellent strength and toughness and three or more crowns. CONSTITUTION:Ceramic constituting porcelain is made of a porous layer comprising spherical alumina and alumina fine powder. Since this porous ceramic layer has no cracks caused by shrinkage in burning, acts as a structural material to secure strength and toughness as a porcelain core material, particle size of spherical alumina and alumina fine powder constituting ceramic raw material powder is controlled, strength and a pore distribution capable of being impregnated with glass can be secured. Since a dental ceramic material frame of this invention is impregnated with glass, strength and toughness as a ceramic core material is ensured. Further, since a glass composition for impregnation contains La2O3 and Al2O3 and ZrO2 or Y2O3, viscosity advantageous for improvement in strength and hardness and impregnation can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental porcelain frame for restoration of anterior prosthesis and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, when a part or some of natural teeth are lost due to a disease such as tooth decay or an accident, prosthetic restoration is performed with artificial teeth made of ceramics, that is, metal-baked porcelain. The metal-baked porcelain is obtained by baking porcelain, that is, dental porcelain (hereinafter referred to as porcelain) in a portion that touches the appearance, and using metal, that is, a porcelain-baking alloy, in a portion that is not related to the appearance.

However, since the structure of this metal-baked porcelain is lined with a metal and 0.8 to 1.2 mm of porcelain is baked on the structure, incident light is blocked and reflected at this portion. Therefore, there is a drawback that the opaque layer baked in contact with the metal surface is strongly influenced, and a high reflectance and a raised color tone are likely to occur.
Moreover, it takes many years of skill to reproduce a natural color tone in this limited structure.

Therefore, from the viewpoint of color tone, an all-ceramic crown without a metal backing has attracted attention, and various porcelains have been proposed. For example, a glass dispersion strengthening method (conventional example A) for strengthening by dispersing a porcelain crystal (quartz, alumina) having high strength and elasticity in a glass matrix phase, alumina whiskers (whisker crystal)
Dispersion strengthening method of glass (conventional example B), a composite material in which an alumina high-concentration material (alumina 75% or more) is coated with an alumina sporoselene veneer layer (conventional example C), or a material in which mica crystals are deposited in glass or Examples include feldspar-based glass mixed with Al ₂ O ₃ as an aggregate (conventional example D) and generation of a stress surface layer in porcelain by ion exchange (conventional example E).

[0005]

However, ceramics themselves are significantly inferior in strength and toughness to metals, and none of the above proposals are satisfactory in terms of strength and toughness. That is, the bending strength and fracture toughness of the conventional material are as shown in Table 1.

[0006]

[Table 1]

Therefore, even if an all-ceramic crown is manufactured from the above-mentioned conventional material, the strength as a ceramic core material is insufficient, so it is difficult to manufacture only a single crown at most, and bridges with three or more crowns are manufactured at all. The current situation is that we cannot do it. Although the conventional example C is sufficient in strength as a dental porcelain frame, it has a drawback that the shrinkage during firing is large and cracks occur, and it has not been put to practical use as an all-ceramic crown. ..

The present invention has been made in view of the above-mentioned problem that conventional porcelain for all-ceramic crown is inferior in strength and toughness and can produce only a single crown at most, and is sufficient as a ceramic core material. It is an object of the present invention to provide a dental porcelain frame having strength and toughness and capable of producing not only a single crown but also a bridge having three or more crowns, and a method for manufacturing the same.

[0009]

SUMMARY OF THE INVENTION The inventors of the present invention first considered that in conventional porcelain, when an attempt was made to give ceramics a desired strength, shrinkage caused by shrinkage occurred during firing. We have repeatedly studied how to prevent the occurrence of. As a result, it was newly found that when the ceramic layer is made porous, cracks due to shrinkage do not occur. Further, in order to make the ceramic layer porous and further improve the strength, it is extremely effective to use a powder raw material composed of spherical alumina particles and alumina fine particles having a certain size or less. It was found that a pore distribution that can be impregnated with is obtained.

Next, in order to solve the above-mentioned problems, the inventors of the present invention thought of impregnating the porous ceramic layer with glass, and made repeated studies on the impregnating glass with which the porous ceramic layer was impregnated. the ₂ O ₃ glass strength and hard increase further in view of the favorable viscosity for impregnation and act as an achromatic agent and the Al ₂ O ₃ in terms of strength and hardness increase of the glass, it contains a predetermined amount The present invention has been completed by finding that the borosilicate glass to be used is extremely advantageous, and that the addition of ZrO ₂ or Y ₂ O ₃ to this glass material can further improve the strength. Further, as a color tone adjusting oxide, Fe
_{By using 2} O ₃ , MnO ₂ and CeO ₂ , it became possible to adjust the color tone without deterioration of the characteristics.

The dental porcelain frame of the present invention uses spherical alumina particles having an average particle size of 0.5 μm to 10.0 μm and alumina fine particles having an average particle size of 0.5 μm to 1.5 μm as powder raw materials. The gist is that it is composed of porous ceramics and glass impregnated into the porous ceramics. In addition, the method for manufacturing a dental porcelain frame of the present invention uses spherical alumina particles having an average particle size of 0.5 μm to 10.0 μm and alumina fine particles having an average particle size of 0.5 μm to 1.5 μm as powder raw materials. The gist is that it comprises a step of firing the porous ceramic material and a step of impregnating the porous ceramic material with glass.

The proportion of the alumina fine particles in the powder raw material is preferably 2 to 40% by weight. And
By setting the density of the porous ceramics to 62.0% or more, the effect of the present invention is further improved.

Further, the glass has B as its constituent component.
It is preferably composed of ₂ O ₃ , SiO ₂ , Al ₂ O ₃ and La ₂ O ₃ and contains ZrO ₂ or Y ₂ O ₃ as an additive component. Furthermore, by setting the molar ratio of B ₂ O ₃ and SiO ₂ which are the constituent components of the glass to the ratio shown by the following equation,
The effect of the invention is further improved. B ₂ O ₃ / (B ₂ O ₃ + SiO ₂ ) = 0.3 mol% or more

The glass contains Fe as a color adjusting oxide.
₂ O _3, MnO _2, 1 kind selected from CeO ₂ or 2
More than one species can be included.

In the present invention, the ceramic core can be formed by a conventionally known method. For example, a method may be used in which ceramic powder is melted with water, built up on a model, and then condensed. Further, the formed ceramic core is preferably fired at a temperature of about 1100 ° C., which is the most common firing temperature for dental porcelain, for about 2 hours. The heating rate is appropriately selected according to the material of ceramics, the method of building, and the like.

It is preferable to impregnate the fired porous ceramic layer with glass at a temperature slightly lower than the firing temperature for 4 to 6 hours. The heating rate is appropriately selected according to the material of ceramics, the method of building, and the like.

[0017]

In the present invention, a porous layer is formed by using spherical alumina having an average particle size of 0.5 μm to 10.0 μm and alumina fine particles having an average particle size of 0.5 μm to 1.5 μm as the ceramic constituting porcelain. Therefore, no cracks are generated due to shrinkage during firing. Moreover, this porous ceramic layer acts as a structural material that secures the strength and toughness of the porcelain core material, and the combination of spherical particles and fine particles can secure the strength and the pore distribution that can be impregnated with glass. In addition to this, it is easy to build up the ceramic layer with a brush and to form it by a dipping method.

In the dental porcelain frame of the present invention, since the porous ceramic layer is impregnated with glass, strength and toughness are secured as the ceramic core material. Further, since the impregnating glass contains Al ₂ O ₃ and La ₂ O ₃ , it not only enhances the strength and hardness, but also secures a viscosity advantageous for impregnation and acts as a physical decolorizing agent for the glass. ,
It is possible to reproduce a color tone with an excellent natural feeling.

In addition, ZrO ₂ or Y _{2 is} added as an additive component.
By containing O ₃ , the strength can be further improved. Further, MnO ₂ contained as a color tone adjusting oxide is from brown to purple, Fe ₂ O ₃ is red, CeO ₂ is contained.
Can be colored in any color from yellow to brown. Further, CeO ₂ is also effective in preventing discoloration due to changes with time due to sunlight.

In the present invention, the alumina particles used as the ceramic powder raw material have a spherical particle shape and an average particle diameter of 0.5 μm to 10.0 μm. This is because a possible pore distribution can be obtained, and by using a powder material having a spherical particle shape, the packing property is improved and the strength as a ceramic core is improved. If the average particle size of the spherical alumina particles is less than 0.5 μm, a sufficient pore distribution cannot be obtained, and conversely, if the average particle size exceeds 10.0 μm, the sinterability decreases and the desired strength cannot be obtained.

The average particle size of the powder raw material is 0.5 μm.
When the proportion of the alumina fine particles having a particle size of ˜1.5 μm is 2 to 40% by weight, the strength as a ceramic core can be increased by improving the sinterability. When the average particle size of the alumina fine particles is less than 0.5 μm, problems such as easy inclusion of bubbles during the production of the alumina core material may occur, and sinterability may occur when the average particle size exceeds 1.5 μm. And the desired strength cannot be obtained. Further, if the compounding ratio of the alumina fine particles is less than 2% of the powder raw material, the above effect cannot be obtained, and if it exceeds 40%, the pore distribution capable of being impregnated with glass cannot be obtained.

In the present invention, the bending strength is set to 3 by setting the density of the porous ceramic to 62.0% or more.
8.9 kg / mm ² or more, fracture toughness 26.8 kg / m
It can be improved to m ^2/3 or more. 62.0% density
In the following cases, the above effect cannot be obtained.

Further, the B ₂ O ₃ and mol ratio of SiO ₂ is a component of the glass in the present invention _{B 2 O 3 / (B 2} O 3 +
By setting SiO ₂ ) = 0.3 mol% or more, desired strength and hardness are imparted to the glass. This mol
If the percentage is less than 0.3%, the above effect cannot be obtained.

[0024]

The preferred embodiments of the present invention will be described in comparison with comparative examples to clarify the effects of the present invention. (Experimental Example 1) Alumina having an average particle size shown in Table 2 was blended at a ratio shown in Table 3, and was heated to 120 ° C for 6 hours and 1120 ° C for 2 hours.
The temperature was raised at a heating rate of 1 hour, and the temperature was maintained at 1120 ° C. for 2 hours to fire the sample composed of the porous ceramic layer. This porous ceramic was impregnated with glass containing the components shown in Table 4 for 20 minutes.
Impregnation was carried out under the impregnation conditions of 1 hour up to 0 ° C., 2 hours up to 1100 ° C. and 6 hours up to 1100 ° C., and the density and strength were measured.

In Table 3, Comparative Examples 1 to 8 use an alumina material having a non-spherical particle shape, and Comparative Example 9 uses spherical alumina but does not include fine alumina particles, Comparative Example In No. 10, the compounding amount of finely divided alumina exceeds the compounding range of the present invention. In Comparative Example 11, the particle size of the finely powdered alumina used exceeds the average particle size of the present invention. In Comparative Examples 12 and 13, the spherical alumina used had a particle size exceeding the average particle size of the present invention. The measured results are summarized in Table 3.

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

As shown in Table 3, Comparative Example 1 in which alumina material A and alumina material B having a non-spherical particle shape were blended
Nos. 6 to 6 had low densities of 1.91 to 2.36 g / cm ^3, and also had large variations in density. Also, because it lacked glass permeability and could not be impregnated with glass,
The strength could not be measured. Comparative Examples 7 and 8 had high densities, but lacked glass permeability and could not be impregnated with glass as in Comparative Examples 1 to 6, so that strength measurement was impossible.

Comparative Example 9 containing the spherical alumina material but not the fine alumina powder had a density of 2.44 g / c.
Although it was as low as m ³ , the glass could be impregnated, but the strength was as low as 25.5 kg / cm ³ . In addition, although the spherical aluminum material was blended, the density of the comparative example 10 in which the fine alumina powder was higher than the composition range of the present invention was 2.71 g.
Although it was as high as / cm ³ , the pore distribution was poor, so
It was impossible to impregnate glass because of poor permeability. In addition, Comparative Examples 11, 12 and 13 using spherical alumina having an average particle diameter of 10.0 μm or more or alumina fine particles having an average particle diameter of 1.5 μm or more,
Although the density was as high as 2.65 to 2.74 g / cm ³ , the hardness and strength of the alumina layer after firing were too weak to withstand use.

On the other hand, in Examples 1 to 8 of the present invention,
2.52 to 2.78 g / c with little variation in density
m ³ (64.0 to 70.6% of theoretical density), the strength after glass impregnation is 29.9 to 40.2 kg / cm ³ , and the strength is remarkably improved, confirming the effect of the present invention. It was

(Experimental Example 2) Using the porous ceramics obtained in Example 3 of Table 3, the glass for impregnation shown in Table 5 was heated to 200 ° C. for 1 hour and 1100 in the same manner as in Experimental Example 1.
Under the impregnation condition of holding for 2 hours at 1100 ° C for 6 hours,
Bending strength (kg / mm ² ) and fracture toughness value (kg / mm ^2/3 ) were measured after impregnation. The obtained results are also shown in Table 5. In Example 3, ZrO was used as the impregnating glass.
_It does not contain ₂ or Y ₂ O ₃ , and Comparative Example 14 has a B ₂ O ₃ / (B ₂ O ₃ + SiO ₂ ) ratio of 0.29 mol%.

[0033]

[Table 5]

As shown in Table 5, in Comparative Example 13 in which the mol% of B ₂ O ₃ was small, the viscosity advantageous for impregnation could not be ensured, so impregnation was impossible, and both bending strength and fracture toughness were not obtained. I could not measure.

On the other hand, Example 3 of the present invention is a comparative example 12 in which the glass for impregnation does not contain ZrO ₂ or Y ₂ O _3.
Had a bending strength of 3 because the strength of the glass was insufficient.
7.7 kg / mm ² , fracture toughness 26.8 kg / mm ^2/3
However, in Examples 9 and 10, the bending strength was 41.
^{35kg / mm 2, 41.37kg / mm} 2, fracture toughness 28.5 kg / mm ^2/3, a 27.2 kg / mm ^2/3, dental porcelain frame superior strength according to the present invention It was confirmed that

[0036]

The dental porcelain frame of the present invention comprises spherical alumina particles having an average particle size of 0.5 μm to 10.0 μm and alumina fine particles having an average particle size of 0.5 μm to 1.5 μm as powder raw materials. The gist consists of a porous ceramic and a glass impregnated into the porous ceramic, and the method for producing a dental porcelain frame of the present invention,
A step of firing a porous ceramic material using spherical alumina having an average particle diameter of 0.5 μm to 10.0 μm and alumina fine particles having an average particle diameter of 0.5 μm to 1.5 μm as a powder raw material; The gist is that it comprises a step of impregnating the material with glass,
Since the ceramic constituting porcelain is a porous layer, there is no occurrence of cracks due to shrinkage during firing, and this porous ceramic layer acts as a structural material that secures strength and toughness as a porcelain core material, Since the ceramic raw material powder is composed of spherical alumina and fine alumina, the strength and the pore distribution capable of being impregnated with glass can be secured by improving the packing property and the sinterability. Further, since the porous porcelain layer of the dental porcelain frame of the present invention is impregnated with glass, strength and toughness are secured as a ceramic core material. Furthermore, the impregnating glass composition has
Since ZrO ₂ and Y ₂ O ₃ are added as an additive containing a ₂ O ₃ and Al ₂ O ₃ , the strength and hardness are improved, the viscosity advantageous for impregnation is secured, and the physical decolorizing agent for glass is used. , And it is possible to reproduce a natural color tone. As a result, the dental porcelain frame material of the present invention is remarkably improved in bending strength and fracture toughness as compared with the conventional example, and is extremely excellent as a dental porcelain frame material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadao Kamiya Nishide, Nishiharu-cho, Nishikasugai-gun, Aichi 177 (72) Inventor Kiyoko Saka 1 701, Kitadamie, Nisshin-cho, Aichi-gun, Aichi

Claims (14)

[Claims] 1. An average particle diameter of 0.5 μm to 10.0 μm
Spherical alumina inside and the average particle diameter is 0.5 μm to 1.
A dental porcelain frame comprising a porous ceramic made of alumina fine particles of 5 μm as a powder raw material and glass impregnated in the porous ceramic. 2. The dental porcelain frame according to claim 1, wherein the proportion of the alumina fine particles in the powder raw material is 2 to 40% by weight. 3. The density of the porous ceramics is 62.
It is 0% or more, The dental porcelain frame of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The glass contains B ₂ O ₃ as a constituent component,
The dental porcelain frame according to any one of claims 1 to 3, which is composed of SiO ₂ , Al ₂ O ₃ and La ₂ O ₃ . 5. Zr as an additive component to the glass
The dental porcelain frame according to any one of claims 1 to 4, which contains O ₂ and Y ₂ O ₃ . 6. B ₂ O ₃ and S, which are constituent components of the glass,
The dental porcelain frame according to any one of claims 1 to 5, wherein the molar ratio of iO _{2 is} a ratio represented by the following formula. B ₂ O ₃ / (B ₂ O ₃ + SiO ₂ ) = 0.3 mol% or more 7. The glass comprises F as a color tone adjusting oxide.
The dental porcelain frame according to any one of claims 1 to 6, which contains one or more selected from e ₂ O ₃ , MnO ₂ , and CeO ₂ . 8. The average particle diameter is 0.5 μm to 10.0 μm.
Spherical alumina inside and the average particle diameter is 0.5 μm to 1.
A method of manufacturing a dental porcelain frame, comprising: a step of firing a porous ceramic material using alumina fine particles having a diameter of 5 μm as a powder raw material; and a step of impregnating the porous ceramic material with glass. 9. The method for manufacturing a dental porcelain frame according to claim 8, wherein the proportion of the alumina fine particles in the powder raw material is 2 to 40% by weight. 10. The density of the porous ceramics is 6
It is 2.0% or more, The manufacturing method of the dental porcelain frame of Claim 8 or Claim 9 characterized by the above-mentioned. 11. The glass comprises B as a constituent component.
_The method for manufacturing a dental porcelain frame according to any one of claims 8 to 10, characterized in that it comprises ₂ O ₃ , SiO ₂ , Al ₂ O ₃ and La ₂ O ₃ . 12. ZrO is added to the glass as an additive component.
The dental porcelain frame according to any one of claims 8 to 11, which contains ₂ , Y ₂ O ₃ . 13. The dental composition according to claim 8, wherein a molar ratio of B ₂ O ₃ and SiO ₂ which are constituent components of the glass is a ratio represented by the following formula. Porcelain frame manufacturing method. B ₂ O ₃ / (B ₂ O ₃ + SiO ₂ ) = 0.3 mol% or more 14. The glass according to claim 8, wherein the glass contains one or more selected from Fe ₂ O ₃ , MnO ₂ and CeO ₂ as a color tone adjusting oxide. The method for manufacturing a dental porcelain frame according to any one of 1.