JP2578076B2 - Dental refractory profile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphate-based dental material which can be used as a tooth base for molding dental crowns, inlays, laminates and the like with ceramics and as an investment material (mold material) for glass casting. The present invention relates to a fire-resistant mold material.

[0002]

2. Description of the Related Art As a method of forming a ceramic dental crown, inlay, and laminate, a dental refractory model material is kneaded with an aqueous solution of colloidal silica to form a tooth base.
An embedding method is known in which firing is repeated several times to apply a mud-like body obtained by kneading ceramic powder with water to the surface of the tooth base with a brush, and firing is performed to obtain a desired shape. The first refractory model material is kneaded with 10 parts by weight of monobasic ammonium phosphate, 10 parts by weight of magnesia clinker having a small diameter of less than 30 μm, and 80 parts by weight of quartz.
There are known a blending example, a second blending example in which 10 parts by weight of quartz in the first blending example is replaced with cristobalite, and a third blending example in which 10 parts by weight of quartz in the first blending example is replaced with tridymite. In addition, attempts have been made to cast the above-mentioned dental crowns and the like using the same compound as the above as an investment material.

[0003]

However, quartz, cristobalite, tridymite, and the like have a transition point, and the coefficient of thermal expansion rapidly increases at the transition point during heating. At the stage of firing, there is a large difference in the coefficient of thermal expansion between the porcelain and the porcelain, such as a crown and an inlay, which causes cracks and shrinkage in the porcelain, and causes the porcelain to peel off or roll off from the boundary of the tooth base. There was a problem. Also, when used as an investment material, even if it is suitable for casting metal, in the case of glass casting or ceramic casting, the coefficient of thermal expansion does not match that of glass or ceramic, similar to the case of the above-mentioned embankment method There were problems such as cracks.

The present invention can be used as a model material for a building method and as an investment material for glass casting or ceramic casting. The difference in the coefficient of thermal expansion between porcelain and glass is small, and It is intended to provide a dental refractory mold for dental use which does not cause cracks in porcelain or glass at the time of casting or rolling up from the boundary with the tooth base and is easy to knead.

[0005]

The first invention comprises 5 to 15 parts by weight of ammonium monophosphate, 5 to 15 parts by weight of magnesia clinker having a particle size of less than 30 μm, 10 to 50 parts by weight of quartz, and 30 to 300 μm in particle size. Is a dental refractory mold comprising 20 to 80 parts by weight of magnesia clinker. That is, the amount of conventional quartz is reduced, and instead, a magnesia clinker having a large particle size is added.

[0006] The second invention is directed to a method for preparing ammonium phosphate monobasic.
A dental refractory mold material comprising 15 parts by weight, 5 to 15 parts by weight of magnesia clinker having a particle size of less than 30 μm, 10 to 50 parts by weight of quartz, and 20 to 80 parts by weight of magnesium silicate. That is, the entire amount of the magnesia clinker having a particle size of 30 to 300 μm of the first invention is replaced with magnesium silicate such as magnesium metasilicate or magnesium orthosilicate (including olivine containing magnesium orthosilicate as a main component). Incidentally, as the magnesium silicate, magnesium orthosilicate is preferable in that it is easily available.

A third invention is directed to a method for preparing a monoammonium phosphate
15 parts by weight, 5 to 15 parts by weight of magnesia clinker having a particle size of less than 30 μm, 10 to 50 parts by weight of quartz, and particle size of 3
A dental refractory mold material comprising a total of 20 to 80 parts by weight of a magnesia clinker of 0 to 300 μm and a magnesium silicate as described above. That is, the particle diameter of the first invention is 30 to
Magnesia clinker of 300 μm is obtained by substituting a part of magnesium silicate such as magnesium metasilicate or magnesium orthosilicate (including olivine mainly containing magnesium orthosilicate), preferably magnesium orthosilicate.

[0008]

The first aspect of the present invention is a magnesia clinker having the property of reducing the quartz content of the conventional compound and instead increasing the coefficient of thermal expansion linearly with temperature.
Since a relatively large magnesia clinker of μm was added, a tooth base was manufactured with the composition of the first invention, and when porcelain was fired, the coefficient of thermal expansion gradually increased with a rise in temperature in a linear manner. There is no crack in the porcelain and no curling at the boundary with the tooth base. Also,
The same applies when a mold is manufactured and glass casting or ceramic casting is performed. However, when the amount of the small magnesia clinker having a particle diameter of less than 30 μm is increased, instead of the large magnesia clinker having a particle diameter of 30 to 300 μm, the kneading is not performed because the reaction proceeds too quickly and the viscosity increases. Will be possible. On the other hand, when only the large magnesia clinker is used, it is not mixed uniformly with other ingredients because of the large particles. When the amount of the large magnesia clinker is less than 20 parts by weight, the effect is too small and no effect is obtained.
If it exceeds 0 parts by weight, the feeling of kneading is poor and 900 ° C.
The difference in the coefficient of thermal expansion between porcelain and glass in the vicinity increases, causing cracks and curling.

[0009] If the amount of the monoammonium phosphate is less than 5%, the strength is reduced. On the other hand, if it exceeds 15 parts by weight, the shrinkage at the time of heating becomes too large and the accuracy is reduced. . When the amount of the magnesia clinker having a particle size of less than 30 μm is less than 5 parts by weight, the strength decreases,
Conversely, when the amount exceeds 15 parts by weight, the curing reaction proceeds too quickly and hardens during kneading. In addition, the compounding amount of quartz is 10
If the amount is less than 100 parts by weight, the difference in thermal expansion coefficient between porcelain and glass at around 900 ° C. becomes large, causing cracks and bending. On the other hand, if it exceeds 50 parts by weight, the influence of the transition point of quartz is exerted. As a result, a large difference in the coefficient of thermal expansion occurs between porcelain and the like at around 573 ° C., and cracks and shrinkage occur in the porcelain and the like.

In the second invention, magnesium silicate having the same thermal expansion coefficient as that of the magnesia clinker is added in the same amount as the large magnesia clinker in place of the large magnesia clinker of the first invention. When the porcelain is manufactured and the porcelain is fired, cracks do not occur in the porcelain and no curling occurs at the boundary between the porcelain and the porcelain. The same applies when used as investment material. However, the amount of magnesium silicate is 20
When the amount is less than part by weight, the effect is too small, and when the amount is more than 80 parts by weight, a difference in thermal expansion coefficient between porcelain and the like at around 900 ° C. becomes large, causing cracks and curling.

In the third invention, a part of the large magnesia clinker of the first invention is replaced with the magnesium silicate of the second invention. Therefore, a tooth base is manufactured with the composition of the third invention, and porcelain is fired. In this case, cracks do not occur in the porcelain as in the first and second inventions, and no bending occurs at the boundary with the tooth base. The same applies when used as investment material. However, when the total amount of the large magnesia clinker and magnesium silicate is less than 20 parts by weight, the effect is too small to have an effect. When the total amount exceeds 80 parts by weight, the heat between porcelain and the like at around 900 ° C. The difference in expansion coefficient becomes large, causing cracks and curling.

[0012]

【Example】

Example 1 10 parts by weight of primary ammonium phosphate, 10 parts by weight of magnesia clinker having a particle size of less than 30 μm, 25 parts by weight of quartz,
15 parts by weight of a colloidal silica aqueous solution was added to a refractory mold material consisting of 30 parts by weight of magnesia clinker having a particle size of 30 to 70 μm and 25 parts by weight of magnesium orthosilicate, and kneaded, and a plate having a thickness of 3.5 mm, a width of 8 mm and a length of 30 mm was obtained. A test piece in the shape of a bar was molded and fired at 1100 ° C. After the test piece was cooled, a porcelain for metal baking ("GSERA Orbit Vest" manufactured by GC Dental Products Co., Ltd.) having a thickness of 1.5 mm was laid on the test piece, and 950 was stacked.
When baked at ℃, the coefficient of thermal expansion of the test piece increases linearly with the temperature, and there is no large difference in coefficient of thermal expansion with porcelain, and it occurs when a large amount of quartz is used The rapid rise in the coefficient of thermal expansion at around 573 ° C. was alleviated, and the occurrence of cracks, shrinkage, floating, curling, etc. was eliminated.

Example 2 Example 1 was repeated except that 30 parts by weight of magnesia clinker having a particle size of 74 to 300 μm was added instead of 30 parts by weight of magnesia clinker having a particle size of 30 to 70 μm.
In the same manner as in Example 1, a fire-resistant mold material of Example 2 was prepared. A test piece similar to that of Example 1 was manufactured using this refractory mold material, and porcelain was laid and fired in the same manner as in Example 1.
As in the case of Example 1, no crack, shrinkage, uplifting or curling occurred.

Example 3 The refractory mold material of Example 3 was prepared in exactly the same manner as in Example 2 except that 30 parts by weight of magnesia clinker having a particle size of 74 to 300 μm was increased to 55 parts by weight, and magnesium orthosilicate was omitted. did. Example 1 using this fire-resistant mold material
When a porcelain was laid up and fired in the same manner as in Example 1, cracks, shrinkage, lifting, turning up, and the like were not generated.

Example 4 Example 4 was carried out in the same manner as in Example 3 except that 55 parts by weight of magnesia clinker having a particle size of 74 to 300 μm were replaced with 55 parts by weight of magnesium orthosilicate.
Was prepared, a test piece similar to that of Example 1 was manufactured using the fire-resistant mold material, and porcelain was laid and fired in the same manner as in Example 1. There was no occurrence of shrinkage, uplift, or curl.

Comparative Example 1 25 parts by weight of quartz of Example 3 was increased to 70 parts by weight.
A fire-resistant mold of Comparative Example 1 was prepared in the same manner as in Example 3, except that 10 parts by weight of tridymite was added instead of 55 parts by weight of magnesia clinker having a particle size of 74 to 300 μm in Example 3. When a test piece similar to that of Example 1 was manufactured using porcelain, and porcelain was laid and fired, a rapid increase in the coefficient of thermal expansion due to tridymite was present at around 150 ° C., and a sudden increase in the coefficient of thermal expansion due to quartz was observed at around 573 ° C. , Cracks occurred in the porcelain.

Comparative Example 2 In Comparative Example 1, except that 10 parts by weight of cristobalite was used instead of 10 parts by weight of the tridymite.
A fire-resistant mold material of Comparative Example 2 was prepared in the same manner as in Comparative Example 1,
A test piece similar to that of Comparative Example 1 was manufactured using this refractory mold material, and porcelain was laid and fired. As a result, a rapid increase in the coefficient of thermal expansion due to cristobalite was present at around 220 ° C. Was present at around 573 ° C., and cracks occurred in the porcelain.

Comparative Example 3 A fire-resistant mold material of Comparative Example 3 was prepared in the same manner as in Comparative Example 1 except that 10 parts by weight of the tridymite was omitted and 70 parts by weight of quartz was increased to 80 parts by weight. And
A test piece similar to that of Comparative Example 1 was manufactured using this refractory mold material, and porcelain was laid and fired. As a result, the rapid increase in the coefficient of thermal expansion due to quartz at about 573 ° C. was larger than that of Comparative Examples 1 and 2. And porcelain had cracks larger than those of Comparative Examples 1 and 2.

[0019]

As described above, the first aspect of the present invention provides
5 to 15 parts by weight of primary ammonium phosphate, particle size 30 μm
5 to 15 parts by weight of magnesia clinker, quartz 10
５０50 parts by weight and 20 to 80 parts by weight of magnesia clinker having a particle size of 30 to 300 μm. The dental refractory mold material has a reduced amount of quartz compared to the conventional ones. Magnesia clinker having a property of increasing in size, particularly having a particle size of 30 to 300 μm
Because it uses a relatively large magnesia clinker, the mold material is used to build a tooth profile base, build up porcelain, fire it, or make a mold and use it for glass casting. The coefficient of thermal expansion increases in a gently linear manner, so that cracks do not occur. In particular, when a tooth base is manufactured, no curling occurs.

The invention according to claim 2 uses magnesium silicate having substantially the same thermal expansion coefficient as that of the magnesia clinker in place of the magnesia clinker having a particle diameter of 30 to 300 μm according to the invention of claim 1. Thus, a tooth base and a mold can be manufactured in the same manner as in the first aspect of the invention, and no cracks occur during porcelain build-up firing or glass casting. In particular, when the tooth base is used, no bending occurs.

The third aspect of the present invention uses the magnesia clinker having a particle size of 30 to 300 μm according to the first aspect of the present invention in combination with the magnesium silicate according to the second aspect of the present invention. A tooth base and a mold can be manufactured in the same manner as in the inventions described in the first and second aspects. No cracks are generated during porcelain build-up firing or glass casting.

Claims (3)

(57) [Claims] 1. A magnesia clinker having a particle size of less than 30 μm.
Parts by weight, 10 to 50 parts by weight of quartz, and particle size of 30 to 300
A refractory dental material consisting of 20 to 80 parts by weight of a magnesia clinker of μm. 2. Magnesium clinker having a particle size of less than 30 μm and a particle size of less than 30 μm.
1 part by weight, 10 to 50 parts by weight of quartz and 20 to 80 parts by weight of magnesium silicate. 3. A magnesia clinker having a particle size of less than 30 μm and a particle size of less than 30 μm.
Parts by weight, 10 to 50 parts by weight of quartz, and particle size of 30 to 30
A refractory dental material comprising a total of 20 to 80 parts by weight of 0 μm magnesia clinker and magnesium silicate.