JPH05194132A - Crystallized glass for restoring deficiency in dentin or tooth and its production - Google Patents

Abstract

PURPOSE:To obtain the subject crystallized glass, useful for restoring a deficiency in the dentin or tooth and capable of providing a restoration with a high accuracy due to its high mechanical strength, cutting properties (workability) and further excellent chemical durability, biocompatibility, aesthetic properties and moldability according to a casting method. CONSTITUTION:The objective crystallized glass for restoring a deficiency in the dentin or tooth has a composition within the ranges of 50-65wt.% SiO2, 3-11wt.% MgO, 8-17wt.% MgF2, 10-18wt.% K2O and 2.5-15wt.% ZrO2 and is obtained by mainly depositing a fluorotetrasilicic mica crystal phase. This crystallized glass has the effects and can be produced by melting oxides and fluorides of the composition as starting materials, forming the resultant melt together with amorphous glass into the same shape as that of the prescribed deficient part in the dentin or tooth, heat-treating the glass and depositing 60-80wt.% fluorotetrasilicic mica crystal phase having 1-2.0+ or -0.5mum average particle diameter in the glass matrix phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to restoration of functions such as occlusion and pronunciation by filling or prosthesis when discoloration, loss, breakage of teeth or lack of teeth due to caries, periodontal disease, trauma or the like. Alternatively, the present invention relates to an artificial material for dentistry, which can restore color tone, form, and the like, and at the same time, can recover aesthetically. More specifically, the present invention, as a material for repairing tooth deficiency or discoloration, or tooth deficiency, is composed of a specific crystal phase and a glass matrix phase of a specific composition, and has excellent physical and chemical properties and excellent aesthetics. The present invention relates to a crystallized glass for repairing tooth substance or tooth defect and a method for producing the same.

[0002]

2. Description of the Related Art One of the major fields of dentistry is the field of restorative medicine for dentine or tooth defects. This is to restore the original tooth structure by using various tooth restoration materials to restore the dentin defect or tooth defect part to a state in which the morphology and structure of the tooth are as close to human teeth as possible. It is intended to recover the existing form and function, that is, improve pronunciation, occlusion, and facial esthetic composition.

The conditions that the above-mentioned tooth restoration material must have are (1) a material that can withstand the masticatory force due to occlusion, such as a material that can withstand physical conditions in the oral environment, (2)
A material that can withstand chemical conditions such as being inert in the oral cavity, (3) a material that does not have a harmful effect on the living body, and (4) a material that has an aesthetic similar to the teeth of a living body. (5) Easy to use (adaptive) technology and reproducible material, (6) Economic cost is low, and manufacturing and application of restoration material is economical in a short time. It is an excellent material.

Currently, clinically used tooth restoration materials are alloys of gold, silver, palladium, nickel, titanium, stainless steel, etc., amalgam alloys, porcelain (ceramic or fine ceramics), high polymer materials and monomers. It is a composite material with a prepolymer and a ceramics filler. In the alloy or the application of the alloy, there is no serious defect in the physical properties, but it is not desirable in a site where aesthetics is important because the constituent materials are significantly different from those of natural teeth. Porcelain is brittle to chew, and polymeric materials are weak and hard to call completely inactive. The metal-bonded porcelain material, which is a combination of alloy and porcelain, is preferable for physical conditions, but sufficient thickness is required to improve aesthetics. Therefore, when the material is used, the amount of tooth substance to be removed increases, and it is technically difficult and there is a problem in economical efficiency. As described above, the completely satisfactory dental restorative material has not been developed up to now as it is considered.

In recent years, in addition to the above materials, it has been proposed to use mica-based crystallized glass as a tooth restoration material.
Physical properties of “castable” ceramic dental restorative materials (Physical preperties of a castable cera
mic dental restorative material). " A.
D. R, Abstracts (59) March 1980, P.474. Further, as a patent relating to the tooth restoration material of the above-mentioned mica-based crystallized glass, there is US Pat. No. 4,431,420.
No. 4,652,312 are known.

By the way, in summary of the above-mentioned US patents, the following techniques are disclosed. (1) dental materials of this patent U.S. Pat. No. 4,421,420, in weight percent on the oxide basis, SiO ₂ 55~65%, MgO 14~19
%, F 4 to 9%, K ₂ O 10 to 18%, and other important components Al ₂ O ₃ 0 to 2%, ZrO ₂ 0
-7%. This US patent corresponds to Japanese Examined Patent Publication No. 3-56731, and in the latter Japanese patent, Sb ₂ O is used as another important component.
It is positioned to use 0 to 2% of ₃ components. (2) U.S. Pat. No. 4,652,312 The dental material of this patent has a SiO ₂ content of 45 to 70% and a MgO content of 13 to 30 in weight percentage on an oxide basis.
%, F 4-9%, K ₂ O 5-20%, BaO 1-4
%, And Al ₂ O ₃ 0-2 as other important components
%, ZrO ₂ 0 to 7%. In particular, this U.S. patent is intended to prevent or control the micropores formed on the surface of the tooth restoration, and for that reason, the BaO component is an essential component.

[0007]

[Problems to be Solved by the Invention] The tooth restoration prepared based on the above-mentioned U.S. Pat. Is hard to say. The cause of destruction by occlusion in the oral cavity is that it must be subjected to an operation of cutting before making a tooth restoration (inlay, crown, etc.) based on the above-mentioned US patent and mounting it in the oral cavity. It is recognized that it is caused by. That is, it is considered that this cutting process causes deterioration in strength and results in damage to the restoration.

The object of the present invention is to satisfy all the properties required for the above-mentioned tooth restorative material, and in particular, the machinability (workability) and the cutting ability which are not provided in the tooth restorative materials of mica glass ceramics up to now. An attempt is made to provide a crystallized glass of mica glass ceramics having a specific composition, which is not found in the prior art, and a method for producing the same, which is characterized by controlling and precipitating a tetrasilicidized fluoromica crystal phase as a main crystal with little strength deterioration due to processing. It is a thing.

[0009]

The present invention will be summarized as follows.
The first aspect of the present invention is that the weight percentage is: SiO ₂ ………… 50 to 65%, MgO ………… 3 to 11%, MgF ₂ ………… 8 to 17%, K ₂ O …………. Crystallization for repairing tooth or tooth defects, characterized in that a tetrasilicidated fluoromica crystal phase is precipitated in the composition range of 10 to 18%, ZrO ₂ ............ 2.5 to 15%. It is about glass.

In the second aspect of the present invention, the weight percentage is: SiO ₂ ............ 50 to 65%, MgO ............ 3 to 11%, MgF ₂ ............ 8 to 17%, K ₂ O ............ 10 ~ 18%, ZrO 2 ............ 2.5~ 15%, with the oxides and fluorides of the composition of the glass of the melted amorphous as a starting material, the melt Molded into the same shape as the predetermined tooth substance or tooth defect, and then heat-treated to give tetrasilicified fluoromica crystal phase having an average particle size of 1 to 2.0 ± 0.5 μm in the glass matrix phase by weight percentage. The present invention relates to a method for producing a crystallized glass for repairing a tooth substance or tooth defect according to the first characteristic point, characterized in that 60 to 80% is deposited.

Thirdly, the present invention thirdly uses the starting material described in the second characteristic point and has an average particle size of 1 to 2.0 ± 0.
When a 5 μm tetrasilicidized fluoromica crystal phase was deposited in the glass matrix phase in an amount of 60 to 80% by weight,
The composition of the remaining 20 to 40% of the glass matrix phase is SiO ₂ ………… 30 to 70%, MgO ………… 0 to 6%, F ………… 0 to 12%, K ₂ O ……. ...... 13 to 30%, ZrO ₂ ............ 10 to 35%, and a method for producing a crystallized glass for repairing a tooth substance or tooth defect according to the first characteristic point.

The fact that the mica-based crystallized glass material has excellent machinability is described in, for example, US Pat. No. 3,689,293.
No. 3732087 and JP-A-62-7649.
And Japanese Patent Laid-Open No. 1-115848.
However, the bending strength of engineering materials such as Macor (made by Corning Glass Works), Macerite (made by Mitsui Mining Co., Ltd.), and Macerite SP (made by Mitsui Mining Co., Ltd.) and artificial marble manufactured using these materials are examined. Is as low as about 1500 Kgf / cm ² or less.

The inventors of the present invention have made extensive studies as to a method for achieving high strength without deterioration of strength of the mica-based crystallized glass, and as a result, the grain size of the mica crystal to be precipitated in the glass matrix phase of the crystallized glass. Found that the size of the sword holds an important key. In addition, as will be described later,
Other important factors are crystallinity, glass matrix phase, and (amorphous phase) composition. That is, in order to manufacture a high-strength mica-based crystallized glass, as shown in FIG. 1, there is an optimum grain size range of mica crystals, and the value has a maximum point of about 1 to 2 μm. I stopped.

In the mica-based crystallized glass, the reason why the strength becomes high in the vicinity of the optimum grain size is that the crack propagation path during the strength test is bent in a zigzag manner along the cleaved surface of the mica crystal. It is thought to be because. However, even if the grain size of the precipitated crystals becomes extremely large or small, it affects the rate of bending (zigzag) that occurs during the course of crack propagation, and this is related to strength deterioration. Conceivable. The present invention proposes the above-mentioned concept, that is, that the optimum grain size should be set in order to achieve high strength, and this point has been overlooked in the prior art.

The present invention is characterized in that the strength is high in the range of the above-mentioned optimum (average) particle size of 1 to 2 ± 0.5 μm. Needless to say,
Needless to say, the range of the optimum crystal grain size of 1 to 2 ± 0.5 μm is influenced by the type of mica crystal, the crystallinity, or the aspect ratio (longitudinal) of the crystal grain size. That is.

Next, with respect to the improvement of the machinability (workability) of crystallized mica glass, as disclosed in the above-mentioned US patent, it is solved by growing a mica crystal which is said to have low hardness to a large size. The approach of saying is generally adopted. Needless to say, this approach is not preferable from the viewpoint of the optimum particle size. On the other hand, a mica-based crystallized glass that can be applied to a tooth restoration material having high machinability by increasing the crystallinity by precipitating a large amount of fine crystals having a predetermined grain size by the present inventor It has been found that can be manufactured. In the present invention, the correlation between crystallinity and machinability (workability) is shown in FIG.

Further, the present inventors have found that increasing the crystallinity increases the bending ratio of the crack propagation path in the strength test, and therefore the crystallinity can be adjusted to produce a high strength material. It turned out to be an important factor.
The crystallinity (wt%) and the strength after cutting (Kgf / cm
The correlation with ² ) is shown in Fig. 3.

From the above, in the production of mica-based crystallized glass, by controlling the crystal grain size and increasing the crystallinity, a material having good machinability (workability) and little deterioration in strength by cutting is obtained. It turned out to be.

Similar to the process disclosed in US Pat. No. 3,732,087, the crystallization process of the present invention proceeds as follows. That is, by heating the molten glass, which is the matrix of the mica-based crystallized glass, at a high temperature, the atoms in the glass become movable and an atomic arrangement is generated. First, above the glass transition point, an atomic arrangement of Mg ²⁺ atoms and F ⁻ atoms starts in the glass so as to lower the free energy, and the crystal phase that precipitates first is according to powder X-ray diffraction (Sellaite Mg
F ₂ ). When heating is further continued, a large number of Si, Mg, K, and O atoms existing around the celite crystal are arranged with the celite as a nucleus and grow into a mica crystal. This is in good agreement with the observation result of disappearance of the X-ray diffraction peak.

Further, based on the above crystallization step,
In the present invention, a method for controlling the grain size of the precipitated crystals of the mica-based crystallized glass to a relatively small grain size of 1 to 2 ± 0.5 μm will be described. As a method of controlling the grain size of such crystals,
For example, the following method may be adopted. 1: Total Mg in the glass that is the matrix of the mica crystallized glass
A composition is adopted in which the amount of F relative to O is increased, in particular, MgF ₂ is included in a large amount and a large amount of celite crystals, which are nuclei for mica crystal precipitation, are precipitated. 2: To control the growth of mica crystals, Zr was used to control the atom transfer in the glass that is the matrix of the mica crystallized glass.
Add O ₂ component. This is because the viscosity of the glass matrix around the crystal that changes momentarily during the precipitation of the mica crystal is Zr.
This is because it is controlled by O ₂ . Further, the addition of ZrO ₂ improves the chemical durability of the glass matrix and prevents dissimilar crystallization of the surface and the inside due to enstatite (MgSiO ₃ ), and further controls the refractive index of the glass matrix and the precipitated crystals, This is because the semi-translucency can be secured and the strength can be improved by the precipitation of fine ZrO ₂ crystals as a by-product.

In the present invention, as a method for improving the crystallinity, as in the case of controlling the growth of mica crystals, a large amount of celite crystals, which are nuclei for the precipitation of mica crystals, may be deposited. Increasing the amount of F relative to the total MgO in the glass that is the matrix of the crystallized glass, and adding ZrO ₂ and the addition of SiO ₂ , MgO, and K ₂ O, which are the constituents of the mica crystal. It is important that the amount be adjusted to the ratio of the tetrasilicidated fluoromica crystals KMg _2.5 Si ₄ O ₁₀ F ₂ and that a small amount of the glass matrix other than the crystal part has a composition that is well compatible with the tetrasilicidated fluoromica crystals. .. To this end, after completion of the heat treatment, i.e. the crystals are in the weight percentage of 60-80%.
The glass composition range of the glass matrix when deposited is SiO ₂ 30 to 70%, MgO 0 to 6.0%,
K ₂ O 13-30%, F 0-12%, ZrO ₂ 1
It is preferably in the range of 0 to 35%, and thus, according to the present invention, the strength, chemical durability and translucency are better than before, and the machinability is good, and the strength deterioration after cutting is small and excellent. A mica-based crystallized glass is obtained.

The glass composition range of the crystallized glass of the present invention is, as a percentage by weight, SiO ₂ ............ 50 to 65%, MgO ............ 3 to 11%, MgF ₂ ............ 8 to 17%. , K ₂ O: 10-18%, ZrO _2: 2.5-15%.

In the glass composition of the above-mentioned crystallized glass of the present invention, when the SiO ₂ content is less than 50%, the chemical durability of the matrix glass phase is extremely deteriorated to 65%.
When it is more, the precipitation of different crystals such as cristobalite increases, the aesthetics deteriorates, the glass viscosity at the time of melting increases, and the formability deteriorates.

When the content of MgO is less than 3%, the degree of crystallinity is lowered, the strength is lowered, and the hardness is increased so that the workability is deteriorated and the strength is deteriorated. On the other hand, when it is more than 11%, enstatite crystals are deposited on the surface during crystallization, cracks occur, the strength is lowered, and the aesthetics and heat resistance are deteriorated.

When MgF ₂ is less than 8%, the crystallinity is lowered, the control of the crystal grain size becomes difficult, and the viscosity at the time of melting the glass increases, so that the formability deteriorates. It also leads to a large amount of precipitation of dissimilar crystals such as enstatite crystals. If MgF ₂ exceeds 17%, the devitrification of the glass increases, and it becomes difficult to control the crystal precipitation.

When the content of K ₂ O is less than 3%, the viscosity at the time of melting the glass is increased and the moldability is deteriorated, and the refractive index of the matrix glass phase is changed, resulting in poor aesthetics.
Sometimes the crystallinity also decreases. If it exceeds 18%, not only the chemical durability of the matrix glass phase is deteriorated but also the heat resistance is deteriorated, and K ₂ O is formed on the surface of the material by heating.
But the aesthetics and translucency deteriorate.

When the content of ZrO ₂ is less than 2.5%, it becomes impossible to control the precipitated crystals, the chemical durability is deteriorated, and it becomes difficult to secure the translucency. On the other hand, if it exceeds 15%,
This leads to a decrease in the crystallinity of mica crystals.

The crystallized glass for repairing tooth substance or tooth defect of the present invention has a semi-translucent milky white color tone, which is very similar to the appearance color tone of human teeth. Needless to say, the color tone of a human body tooth can be made more similar to that of a human body tooth by coloring the above-mentioned material of the present invention because the color tone is slightly different for each human body. As a coloring method, the glass composition of crystallized glass may be colored with CeO ₂ , F ₂ O ₃ , NiO ₂ ,
A method of adding at least one kind of transition metal oxide or noble metal oxide, such as MnO ₂ , halides and salts;
There is a method of applying a color tone material such as glass or porcelain on the surface of the material of the present invention and baking it. When a coloring material is added to the glass composition, it is preferable that the amount is not more than 5% by weight, which is larger than 100% by weight of the glass. When it is more than 5%, it is not preferable because the coloring becomes excessively dark and the crystallization characteristics are affected to lower the crystallinity, resulting in deterioration of physical properties.

Further, in addition to the above-mentioned components, the crystallized glass of the present invention is useful for controlling the properties of alkali metal, alkaline earth metal oxides and matrix glass phase which are compatible with tetrasilicidated fluoromica crystals. Considered to be effective. For example, it is acceptable to add a transition metal or the like up to a total of 10 weights. However, the inclusion of Na ₂ O and LiO ₂ results in swelling mica crystals, which deteriorates the chemical durability and translucency, which is not preferable.

The crystallized glass for repairing tooth defects or tooth defects of the present invention is manufactured as follows. The following production methods should be understood as examples, and the present invention is not limited to these. That is, SiO ₂ composed of the above-mentioned composition 50 to 65%, MgO 3 to 1
1%, MgF ₂ 8-17%, K ₂ O 10-18%,
ZrO ₂ 2.5-15% oxide and fluoride
Amorphous glass is obtained by melting in a platinum crucible with a lid at 00 ° C to 1550 ° C for 2 to 6 hours (hereinafter referred to as an oxide melting method). Next, from this melt, a molded product formed by casting by the lost wax method or the like is added to the crystallization temperature 60
The crystallized glass of the present invention is produced by heat treatment at 0 ° C to 1200 ° C for 1 to 6 hours. In particular, the preferred embodiment of the crystallization method of the present invention is that the heat treatment conditions suitable for precipitating tetrasilicified fluoromica crystals having an average particle size of 1 to 2 ± 0.5 μm in the crystallized glass of the present invention are 600 to
It is selected from a temperature range of 1200 ° C. and a heat treatment time of 1 to 6 hours.

In the present invention, in order to uniformly precipitate tetrasilicidated fluoromica crystals having an average particle size of 1 to 2 ± 0.5 μm in the glass matrix phase, fine crystal nuclei are sufficiently precipitated, It grows and precipitates, and the grain size is 1-2.
It must be grown to a crystal of ± 0.5 μm. As such a method, for example, an oxide and a fluoride having the above-described specific composition are melted as starting materials to form an amorphous glass and molded, and crystal nuclei are precipitated in a cooling process at a glass transition temperature or higher. Then, there are two methods: a method of heat treatment for crystal growth, and a method of once cooling below the glass transition point and then heating again to precipitate crystal nuclei and grow crystals.

In the present invention, the range of crystal nucleus formation is 5
50 ° C. to 750 ° C. (range from glass transition point to slightly higher temperature) is preferable, and holding time at that temperature is 0 to 5 hours. This is because the formation rate of crystal nuclei depends well on the temperature, that is, the glass viscosity, and when the temperature is high, the crystal nucleation is completed in a short time, while when the temperature is low, it takes a long time. Further, since the grain size of the formed crystal nuclei depends on the temperature, that is, the degree of supercooling of the glass, the fine crystal nuclei are preferable as described above.
The temperature may be maintained for 0 to 5 hours in a temperature range from a glass transition point of ˜750 ° C. to a slightly higher range. Thereafter, the crystal nuclei are controlled to grow into mica crystals having an average particle size of 1 to 2 ± 0.5 μm, and the growth rate of this crystal depends on the temperature, that is, the viscosity, like the formation rate of the crystal nuclei. If it is high, the crystal growth is completed by holding heat for a short time, and if it is low, it takes a long time.
From the above, in order to grow the crystal grain size to an average of 1 to 2 ± 0.5 μm, the crystal nucleus forming condition is 550 to 750.
The temperature is 0 ° C., and the holding time is 0 to 5 hours within a suitable range. In the present invention, within the range of the above-mentioned conditions, innumerable methods can be used as a crystallization method. Particularly, when heating at a slow heating rate from the glass transition point of 5 ° C./min No heat treatment process to form nuclei is necessary.

The crystallized glass of the above-mentioned composition of the present invention is
Since it is intended to be used for biomedical treatment, and because aesthetics are strongly demanded, impurities should be minimized as much as possible. For that purpose, the starting materials must be carefully selected, but as one of the methods, it is preferable to use the sol-gel method described below (hereinafter referred to as the sol-gel method). For example, in the above-mentioned composition, the starting material has Si (OC ₂ H ₅ ) ₄ , Mg (OCH ₃ ) ₂ , K as components corresponding to the oxide components.
_{OCH 3, Zr (O-i} -C 4 H 9) 4, metal alkoxides such as, by using a NH ₂ C ₆ H ₄ CF ₃ as a fluorine compound, these in a polar solvent, when the oxide SiO ₂ 50-65%, MgO 3
11%, K ₂ O 10-18%, ZrO ₂ 25-15
%, MgF ₂ 8 to 17% are mixed and dissolved, and water is added to this to tilt PH toward the alkali side, a hydrolysis reaction is performed, and then dehydration drying is performed to prepare a desired glass. it can. Amorphous glass is obtained by melting the glass thus prepared. After molding this into a predetermined shape, it is heat-treated in the temperature range of 600 to 1200 ° C. for 1 to 6 hours in the same manner as described above to control tetrasilicified fluoromica crystals having an average particle diameter of 1 to 2 ± 0.5 μm. It can be deposited.

By the above-mentioned method, that is, the sol-gel method using a metal alkoxide as a starting material of an oxide, a biomaterial having extremely few impurities can be produced, and glass having a low melting temperature can be obtained, so that the energy consumption is small. There is an advantage that. The manufacturing method using the sol-gel method described above will be described more specifically. For example, 102 parts of silicon tetraoxide (Si (OC ₂ H ₅ ) ₄ ), 16 parts of magnesium methoxide (Mg (OCH ₃ ) ₂ ), 9 parts of potassium methoxide (KOCH ₃ ), zirconium tetrabutoxide (Zr (O _{-i-C 4 H 9) 4} 16 parts were dissolved in 1500 parts of ethanol, 3-amino-benzotrifluoride _{(NH 2 C 6 H 4 CF} 3) benzene 5 14 parts
A solution dissolved in 00 parts was added and mixed. Next, water adjusted to PH11 with ammonia was added dropwise (about 200 parts),
When the solution becomes a completely white gel, it is dried at 120 ° C and further heat treated (about 700 to 950 ° C, or 1000 to 13 ° C).
(00 ° C.) to produce a glass raw material. After the glass raw material is melted, it is made amorphous and formed into a desired shape, and then heat treatment for crystallization is performed to convert it into a tetrasilicified fluoromica-based crystallized glass.

In the case of the sol-gel method described above, it is preferable to use an alkoxide having a C ₁ -C ₄ alkyl group as the metal alkoxide compound, and the fluorine compound may be any one as long as it is soluble in a polar solvent. Since 3-aminobenzotrifluoride (NH ₂ C ₆ H ₄ CF ₃ ) is hardly soluble in alcohols or ketones, it was dissolved in benzene which is a nonpolar solvent. 5 for 1 kg of mother glass produced
It is preferred to use ˜13 l of polar solvent.

In the hydrolysis method in the sol-gel method, the amount of water required for the hydrolysis of each alkoxide is preferably 2 to 12 times the theoretical value. Under this usage amount, a relatively uniform gel body can be obtained although the hydrolysis rate varies depending on each alkoxide component, and if the usage amount is deviated, the gel becomes non-uniform, which is not preferable.

In general, the pH of hydrolysis is preferably 6.0 or more, and when it is less than 6.0, the hydrolysis rate becomes slow and a non-uniform gel is produced, and Mg ₂ SiO ₄ etc. are generated in the composition. Is not preferable. The hydrolysis temperature is generally in the range of 20 to 100 ° C., and particularly 60 to 6
About 5 ° C is preferable. After the solution becomes a completely white gel, it is dried at 100 to 150 ° C., and the dried body is subsequently heat-treated at 700 to 950 ° C. or 1000 to 1300 ° C. to obtain an amorphous glass. This amorphous glass is melted again, shaped into a desired shape, and heat-treated in the range of 600 to 1100 ° C. for 1 to 6 hours to give an average of 1 to 2
A crystallized glass having excellent transparency is obtained by depositing a tetrasilicidated fluoromica crystal phase having a particle diameter of ± 0.5 μm in a glass matrix phase in an amount of 60 to 80% by weight. The crystallized glass prepared by the sol-gel method described above did not change in crystallinity or characteristics as compared with those manufactured by the oxide melting method.

A casting method or the like is adopted as the molding method of the present invention, and a centrifugal casting method or a vacuum pressure casting method is used as the casting method. In the centrifugal casting method, a refractory casting mold made by the lost wax method is set in a spring type or motor type centrifugal casting machine, the glass raw material of the present invention is melted and an appropriate amount is poured into a casting mold crucible, and immediately subjected to centrifugal rotation. After starting, glass is cast in a casting mold to obtain a molded product. Further, in the vacuum pressure casting method, the glass raw material of the present invention is put in a platinum or heat-resistant magnetic container, the glass raw material is melted by a heater set around the container, and then the inside of the caster is -60 to 70 mm by a vacuum pump. / The pressure is reduced in mercury, and the molten glass is immediately pressurized at 2-3 atmospheric pressure to perform casting. It goes without saying that, in the molding method of the present invention, the glass composition of the crystallized glass of the present invention can be melted, molded and cooled once as glass pellets, and then melted again to be cast by the above method.

[0039]

EXAMPLES The present invention will now be described in more detail with reference to Examples. Needless to say, the present invention is not limited to the examples. Table 1 below shows the glass compositions of Examples (1 to 8) and Comparative Examples (1 to 2) used for preparing crystallized glass for repairing tooth defects or tooth defects. Incidentally, those of Comparative Examples 1 and 2 are disclosed in JP-A-47-2.
The composition described in No. 1420 is adopted. Also,
In Table 1, the oxide melting method means that the starting material was prepared with an oxide and a fluoride, and the sol-gel method means that the starting material was prepared with a metal alkoxide and a fluoride.

[0040]

[Table 1]

Starting materials were oxides and fluorides adjusted to have the compositions shown in Table 1 of Examples 1 to 6 and Comparative Examples 1 and 2, and they were placed in a platinum crucible with a lid and placed in an electric furnace for about 14 minutes.
It was melted at 50 ° C. for about 4 hours. On the other hand, in Examples 7 to 8, glass was prepared by using the sol-gel method (the composition of the oxide is exactly the same as in Examples 5 and 6 as shown in Table 1). ), The glass at about 700-950 ° C or about 1000-1300 ° C at about 4 ° C.
Thawed for hours. Then, these molten glasses were molded into blocks and heat-treated at 950 to 1050 ° C. for about 2 to 6 hours as shown in Table 2 to produce crystallized glass. Next, when the crystal phase of each crystallized glass was observed by the powder X-ray diffraction method, tetrasilicified fluoromica-based crystals were precipitated in all the crystallized glasses. Then, the crystallinity was measured using a calibration curve from the peak height of X-ray diffraction, and the crystallinity was also confirmed by an electron microscope (SEM) to determine the average particle size of tetrasilicidated fluoromica crystals. In addition, various crystallized glass prepared as described above was used as a 3 × 4 × 36 mm prism.
It was processed into a 0 × 10 × 20 mm prism, a 20 × 20 × 5 mm prism plate, and a φ8 × 1 mm plate, and various physical properties shown in Table 2 were evaluated.

(1) Bending strength was determined by subjecting crystallized glass formed into a prism of 3 × 4 × 36 mm to scratches with a # 320 abrasive paper under anhydrous conditions, and then by a test method according to JIS R 1601. It is measured at a span of 30 mm and a crosshead speed of 0.5 mm / min. (2) The workability was evaluated by displaying the cutting amount when cutting a 10 × 10 × 20 mm prism using a dental air turbine and an electric engine in two grades, excellent and good. (3) Chemical durability was measured by measuring the weight loss relative to the surface area after immersion in a 0.5% HCl aqueous solution at 37 ° C. for 24 hours using crystallized glass obtained by mirror-finishing a 20 × 20 × 5 mm plate. is there. (4) Biocompatibility was determined by culturing human skin fibroblasts on a plate processed with φ8 × 1 mm crystallized glass with a mirror surface and a rough surface for 48 hours at 37 ° C. to determine the degree of cell growth. It was evaluated on a two-grade scale. (5) As for biotoxicity, a sterilized processed plate of φ8 × 1 mm is shaved on a rat back of 70 to 80 g for about φ10 mm,
An 8 mm skin incision was made, and the skin was peeled off to form a capsule, which was transferred into the capsule and the skin was sutured. One month later, the rat was slaughtered, the transferred part was excised, pathological tissue sections were prepared by conventional methods, and microscopic observation was performed. Those that did not show inflammatory findings and remained in the tissue (excellent), slightly inflammatory. In all cases, the transfer plate (processed plate) was covered with a thin connective tissue membrane, which was judged to be excellent (good) or inflammatory (good). Therefore, it was retained in the tissue without harm. Table 2 shows the above evaluation results.

[0043]

[Table 2]

When the bending strength and workability of the crystallized glass of the present invention (Examples 1 to 8) and the conventional products (Comparative Examples 1 and 2) are compared, the crystallized glass of the present invention has high bending strength and workability. It is clear that it is superior to. Further, it can be seen that the chemical durability and the biocompatibility are very good and there is no harm to the living body.

<Application Example> Next, an application example in which a gypsum model is made by impressing a form of repairing a tooth having a tooth defect and a jacket crown whose defective portion covers the entire crown is required, It was tested whether the crystallized glass of the invention was effective. That is, paraffin wax (inlay wax) is melt-laid on the model to form a crown wax pattern, and a spool wax wire for introducing molten glass is welded, and then, an ethyl silicate silica embedding material or a phosphate embedding material. Buried in wood. After the investment material was cured, the temperature was raised to 900 ° C. to incinerate the wax pattern to make a crown mold. On the other hand, glass obtained by melting the glass pellet of the present invention at 1300 to 1550 ° C. was poured into a crucible on the upper surface of the crown mold and cast using a centrifugal casting machine. After the casting has cooled, it is removed from the mold
It heat-processed at 1050 degreeC for 2 to 6 hours, and was made to crystallize.
The glass composition of the present invention exhibits physical properties equivalent to those of human teeth and exhibits good semi-translucency, that is, an opal effect. In particular, those of Examples 1 and 2 containing a coloring material It had a color tone similar to that of a tooth and was extremely aesthetic. The glass composition of the present invention using the sol-gel method exhibited a more beautiful translucency or opal effect.
In addition, the crystallized glass of the present invention shows very good biocompatibility and harm, and it can be seen that it is excellent as a biomaterial.

[0046]

INDUSTRIAL APPLICABILITY The crystallized glass for repairing tooth deficiency or tooth deficiency produced by the method of the present invention has excellent chemical durability and biocompatibility in addition to high mechanical strength and cutting control (workability). It is suitable for obtaining restorations with high dimensional accuracy (inlays, crowns, bridges, artificial teeth, etc.) because it has both good and aesthetic properties and can be molded by a casting method. The crystallized glass of the present invention is CA
D, CAM method for restoration of tooth structure (inlay, crown)
Needless to say, it can be used as a cutting material for the above, and also as a model tooth for cutting training and viewing in the dental education process.

[Brief description of drawings]

FIG. 1 Mica particle size (μm) of mica-based crystallized glass
It is a graph which shows the relationship between and the strength after cutting.

FIG. 2 is a graph showing the relationship between crystallinity and machinability of mica-based crystallized glass.

FIG. 3 is a graph showing the relationship between the crystallinity of mica-based crystallized glass and the strength after cutting.

Claims (8)

[Claims] 1. A weight percentage of SiO ₂ ............ 50 to 65%, MgO ............ 3 to 11%, MgF ₂ ............ 8 to 17%, K ₂ O ............ 10 to 18%, ZrO ₂ ............ 2.5 to 15%, and a crystallized glass for repairing tooth defects or tooth defects, characterized in that a tetrasilicidated fluoromica crystal phase is mainly precipitated. .. 2. The weight percentage is SiO ₂ ............ 50 to 65%, MgO ............ 3 to 11%, MgF ₂ ............ 8 to 17%, K ₂ O ............ 10 ~. 18%, ZrO ₂ ...... 2.5 to 15%, is used as a starting material to melt the oxides and fluorides to form amorphous glass. Molding into the same shape as the defect portion, and then heat treating to deposit a tetrasilicidated fluoromica crystal phase having an average particle size of 1 to 2.0 ± 0.5 μm in the glass matrix phase in a weight percentage of 60 to 80%. The method for producing a crystallized glass for repairing a tooth substance or tooth defect according to claim 1. 3. When a tetrasilicidated fluoromica crystal phase having an average particle size of 1 to 2.0 ± 0.5 μm is precipitated in a glass matrix phase in an amount of 60 to 80% by weight, the remaining 20
The composition of the glass matox phase of ˜40% is SiO ₂ ………… 30 to 70%, MgO ………… 0 to 6%, F ………… 0 to 12%, K ₂ O ………… 13 30% a process according to claim 2, wherein the ZrO ₂ ............ 10~35%, a. 4. The production method according to claim 2, wherein the method of forming the melt into the same shape as a predetermined tooth substance or a tooth defect portion is a lost wax method. 5. The heat treatment is a heat treatment in the temperature range of 600 to 1200 ° C. for 1 to 6 hours, and the average particle size is 1 to 2.0 ±.
The method according to claim 2 or 3, characterized in that a 0.5 µm tetrasilicidized fluoromica crystal phase is precipitated in a glass matrix phase in a weight percentage of 60 to 80%. 6. The oxide of the composition according to claim 2, when the metal alkoxide and the fluoride are used to form the oxide and the fluoride, the weight percentage is SiO ₂ ... 50-65%, MgO. ………… 3 to 11%, K ₂ O ………… 10 to 18%, ZrO ₂ ………… 2.5 to 15%, MgF ₂ ………… 8 to 17% in the solvent. The method according to claim 2, 3, 4, or 5, which is prepared by mixing and dissolving in, and then hydrolyzing. 7. The oxide and the fluoride having the composition according to claim 2, when the oxide and the fluoride are converted into the oxide and the fluoride by using a metal alkoxide and a fluorine-containing compound, SiO ₂ ............ 50 〜65%, MgO ………… 3 to 11%, K ₂ O ………… 10 to 18%, ZrO ₂ ………… 2.5 to 15%, MgF ₂ ………… 8 to 17% The method according to claim 2, 3, 4 or 5, which is prepared by mixing and dissolving in a solvent in the following proportions and then performing a hydrolysis reaction. 8. The oxide having the composition according to claim 7 is a metal alkoxide Si (OC ₂ H ₅ ) ₄ , Mg (OC).
_{H 3) 2, KOCH 3,} Zr (OC 4 H 9) _4;
The method according to claim 2, ₃ , 4 or 5, wherein the fluorine-containing compound is NH ₂ C ₆ H ₄ CF ₃ .