KR101616947B1 - Coloring method of glass-ceramics for dental applications - Google Patents

Abstract

Disclosed is coloring of crystallized glass for artificial teeth capable of forming uniform colors by adding coloring additives without degrading material properties so as to express colors of A, B, C, and D groups of a Vita shade guide, a standard of teeth colors. The coloring crystallized glass for artificial teeth in accordance with the present invention comprises the following steps: (a) forming a coloring mixture by mixing coloring additives with a raw material of glass containing SiO_2, MgO, Al_2O_3, and a nucleating seed; (b) primarily grinding the coloring mixture; (c) primarily melting the ground coloring mixture and then cooling the same to form primary glass; (d) secondarily grinding the primary glass; (e) secondarily melting the primary glass and then cooling the same to form secondary glass; and (f) treating the secondary glass with heat for crystallization and then cooling the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for coloring a crystallized glass for artificial teeth,

The present invention relates to a method of coloring a crystallized glass for artificial teeth, and more particularly, to a method of coloring a crystallized glass for an artificial tooth by reducing the physical properties so as to realize colors A, B, C, and D of a Vita shade guide The present invention relates to a method of coloring a crystallized glass for artificial teeth capable of realizing a uniform color by adding a coloring additive within a range not exceeding a predetermined range.

As the world enters the aging society, tooth related diseases such as periodontal diseases and dental caries are becoming social issues. In addition, the demand for dental materials has increased rapidly due to the increase of economic income and improvement of living culture.

Aesthetic restorations in the field of dental prosthetics Developers are working to develop materials that are close to natural teeth in order to meet the patient's economic and product satisfaction. In particular, ceramics are used for chemical inertness, abrasion resistance, biocompatibility, And is used as an esthetic restorative material in dental prosthesis field.

The porcelain includes an inner coping and a so-called bottom and a top called a crown.

Porcelain Fused to Metal Crown (PFM), which uses metal as a lower part of porcelain, is used because of problems such as metal shrinkage and corrosion allergy, and all-ceramics restoration Systems, and its coverage extends from anterior to posterior.

The complete ceramic tube is capable of realizing color close to the natural value, and since the metal does not enter the interior of the prosthesis, it is possible to reproduce the optical characteristics of the enamel and dentin, and has excellent chemical stability and biocompatibility.

However, it is weak against tensile stress and impact due to brittleness inherent in ceramic, and has a disadvantage in that it is difficult to control precise dimensions due to large shrinkage upon firing. Therefore, various studies are under way to improve this.

Existing restorative materials used as complete rehabilitation include glass infiltration ceramics and zirconia.

Glass infiltration ceramics are produced by infiltrating molten glass into porous ceramics. Glass-infiltrated ceramics crown has excellent mechanical strength but low transparency in visible light region, resulting in poor esthetics and complicated manufacturing process.

Zirconia has a high strength and toughness by using stabilized zirconia composition, so it has wide application areas such as coping, crown, upper support. However, the zirconia block production method has a disadvantage in that the process is complicated, expensive equipment is used, and color implementation is difficult. In addition, zirconia has a somewhat turbid unique color, and in the case of a coping or crown of a zirconia material, there is a problem that the aesthetic property is deteriorated.

In general, since the color of teeth varies considerably from patient to patient, it is important to achieve precise coloring of existing natural teeth by patient. However, crystallized glass or zirconia, which is now commercially available as an artificial tooth, has inherent color, which makes it difficult to implement color and adjust color.

In recent years, in order to solve such a problem, there has been attempted to prepare a solution containing a coloring element in crystallized glass or zirconia and then coloring it by spraying. In this case, a manufacturing process for spray coating is added, There is a problem that the color is unevenly realized due to the characteristics of the spray coating.

As a related prior art, Korean Patent Laid-Open Publication No. 10-2012-0073710 (published on Jul. 5, 2012) discloses high strength crystallized glass for teeth including lithium disilicate crystals.

The object of the present invention is to provide a method for coloring A, B, C, and D of a Vita shade guide, which is a teeth color reference chart, by adding a coloring additive within a range that does not deteriorate physical properties, The present invention provides a method of coloring crystallized glass for artificial teeth.

According to an aspect of the present invention, there is provided a method of forming a crystallized glass for artificial teeth comprising the steps of: (a) adding a coloring additive to a glass raw material containing SiO ₂ , MgO, Al ₂ O ₃ and a nucleation seed; Mixing to form a colored mixture; (b) firstly pulverizing the colored mixture; (c) forming a primary glass by first melting the primary milled color mixture and cooling the primary mixture; (d) secondarily grinding the primary glass; (e) secondarily melting the secondary milled primary glass and then cooling to form a secondary glass; And (f) subjecting the secondary glass to a crystallization heat treatment followed by cooling.

Since the method of coloring crystallized glass for artificial teeth according to the present invention shows bright white when crystallized by performing a crystallization heat treatment only on a glass raw material which is a starting material in the production of crystallized glass for artificial teeth, If coloring is performed by simply adding an additive, it is possible to realize uniform color easily without deteriorating the inherent physical properties of the crystallized glass for artificial teeth, and to exert excellent esthetics.

Therefore, the crystallized glass produced by the coloring method of the crystallized glass for artificial teeth according to the present invention can exhibit excellent physical properties and aesthetics due to uniform color reproduction, and thus is suitable for use as a material for coping or crowns of artificial teeth.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process flow chart showing a method of coloring crystallized glass for artificial teeth according to an embodiment of the present invention. FIG.
2 is a view showing a tooth shade guide which is a teeth color reference chart.
3 is a photograph showing the crystallized glass colored by the method according to Examples 1 to 8.
4 is a photograph showing the crystallized glass colored by the method according to Examples 9 to 16. Fig.
Fig. 5 is a photograph showing the crystallized glass colored by the method according to Examples 17 to 24. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, a method for coloring a crystallized glass for artificial teeth according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process flow chart showing a method of coloring crystallized glass for artificial teeth according to an embodiment of the present invention. FIG.

Referring to FIG. 1, the coloring method of the crystallized glass for an artificial tooth shown in FIG. 1 includes a coloring mixture forming step (S110), a primary grinding step (S120), a primary glass forming step (S130), a secondary grinding step (S140) A secondary glass forming step S150 and a crystallization heat treatment step S160.

Color mixture formation

The coloring mixture forming step (S110) by mixing a coloring additive to the glass raw material containing _{SiO 2, MgO, Al 2 O} 3 and a nucleation seed (seed) to form a colored mixture.

The glass raw materials for producing the crystallized glass for artificial teeth according to the present invention include SiO ₂ , MgO, Al ₂ O ₃ and nucleation seeds.

SiO ₂ serves to form crystals and glass network structures. The SiO ₂ is preferably added in a content ratio of 45 to 47% by weight based on the total weight of the glass raw material. When the content of SiO ₂ is less than 45% by weight, the light transmittance of glass may be lowered. On the other hand, when the content of SiO ₂ exceeds 47 wt%, the strength and toughness may be insufficient.

MgO contributes to an increase in crystallinity and a decrease in viscosity. The MgO is preferably added in an amount of 11 to 13% by weight based on the total weight of the glass raw material. If the amount of MgO added is less than 11 wt%, the effect of the addition is insufficient, and if it exceeds 13 wt%, the light transmittance may be lowered.

Al ₂ O ₃ contributes to improvement of flexural strength and fracture toughness. Al ₂ O ₃ is preferably added at a content ratio of 31 to 33% by weight based on the total weight of the glass raw material. When the content of Al ₂ O ₃ is less than 31 wt%, the effect of improving flexural strength and fracture toughness is insufficient. On the contrary, when the content of Al ₂ O ₃ exceeds 33% by weight, crystallization may be deteriorated.

The nucleation seed acts as a nucleating agent for crystallization. These nucleation seeds may be at least one of ZrO ₂ and TiO ₂ . The content of nucleation seeds is preferably added in a content ratio of 9-11% by weight of the total weight of the mixture. When the content of the nucleation seed is less than 9 wt%, the crystallization is insufficient, and when the content of the nucleation seed is more than 11 wt%, the light transmittance may deteriorate.

2 is a view showing a tooth shade guide which is a teeth color reference chart.

Referring to FIG. 2, it is preferable that the coloring additive is added in such a range as not to deteriorate the physical properties so as to realize colors of the A, B, C, and D series of the Vita shade guide, which is a teeth color reference chart.

In the present invention, since crystallization heat treatment is performed only on a glass raw material which is a starting material in the production of a crystallized glass for an artificial tooth, it shows a bright white when crystallized. Therefore, by adding a small amount of a coloring additive to a glass raw material, The uniform color can be easily realized without deteriorating the inherent physical properties of the crystallized glass for artificial teeth, and excellent aesthetics can be exhibited.

Therefore, the coloring method of the crystallized glass for artificial teeth according to the embodiment of the present invention is not a method in which a solution containing a coloring element is colored by a spray coating method, but a coloring additive is directly added to a glass raw material, So that a separate process such as spray coating can be omitted, and it becomes possible to realize a uniform color since it is mixed into the glass raw material.

At least one of oxides such as Er, Fe, Cr, Mn, Ti, V, Co, Ce and Y may be used as the coloring additive. More preferably, the coloring additive is selected from the group consisting of Er ₂ O ₃ , Fe ₂ O ₃ , Cr ₂ O ₃ , Mn ₂ O ₃ , Ti ₂ O ₃ , V ₂ O ₃ , Co ₂ O _{3 ,} CeO ₂ and Y ₂ O ₃ It is appropriate to include at least one selected.

At this time, the coloring additive is preferably added in a content ratio of 0.0005 to 0.003 mol%. If the addition amount of the coloring additive is less than 0.0005 mol%, the addition amount thereof is insufficient and it is difficult to exhibit the coloring effect properly. On the other hand, when the addition amount of the coloring additive exceeds 0.003 mol%, the physical properties of the crystallized glass may be lowered without further increasing the effect.

Primary grinding

Referring to FIG. 1, in the primary pulverization step (S120), the colored mixture is first pulverized. At this time, the primary pulverization can be performed by ball milling, which facilitates even mixing and pulverization of raw materials in a powder state.

Primary glass formation

In the primary glass forming step (S130), the primary crushed colored mixture is first melted and then cooled to form primary glass.

In this step, the primary melting can be performed at about 1500 ° C or higher.

At this time, it is preferable that the cooling is performed by a water quenching method so as to shorten the process time and facilitate secondary pulverization, so that the primary glass is formed into a piece of glass.

When only secondary melting is performed, the homogeneity of the glass is low and cracks can easily occur. To solve this problem, in the present invention, the primary glass is formed through the primary melting and the secondary glass is formed through the secondary melting. As a result, the homogeneity of the crystallized glass composition and physical properties could be improved.

Secondary grinding

In the secondary pulverization step (S140), the primary glass is secondarily pulverized. The secondary pulverization can be carried out in a mortar to a size of about 1 mm or less.

Secondary glass formation

In the secondary glass forming step (S150), the secondary pulverized primary glass is secondarily melted and then cooled to form secondary glass.

At this time, for molding, after the second melting, the molten material may be cooled in a state where it is put in the mold.

At this time, it is preferable that cooling is performed in a cooling in furnace system. The secondary glass is already molded, and when air or water cooling is applied, internal stress is severely formed in the secondary glass, and in some cases, cracks may occur. Cooling of the secondary glass is preferably cooled.

Crystallization heat treatment

In the crystallization heat treatment step (S160), the secondary glass is subjected to crystallization heat treatment and then cooled to produce crystallized glass for artificial teeth which has finally been colored.

At this time, the crystallization heat treatment is preferably performed at 1,000 to 1100 ° C for 1 to 4 hours. If the crystallization heat treatment temperature is less than 1,000 ° C, crystallization may be insufficient. On the contrary, when the crystallization heat treatment temperature exceeds 1,100 DEG C, it acts only as a factor to increase the manufacturing cost and time without further increasing the effect, which is not economical.

The cooling can be performed in a furnace-cooling manner.

Meanwhile, the heat treatment may be performed in two steps, including a step of preliminary heat treatment of the secondary glass at 800 to 900 ° C prior to the crystallization heat treatment step (S160). As described above, when the crystallization heat treatment is performed by the two-stage multi-stage heat treatment, a more stable crystallized glass can be formed as compared with the single-stage heat treatment.

As described above, since the coloring method of the crystallized glass for artificial teeth according to the present invention shows bright white when crystallized by performing the crystallization heat treatment only on the glass raw material which is the starting material in the production of the crystallized glass for artificial teeth, When coloring is performed by simply adding a small amount of a coloring additive to a glass raw material, a uniform color can be easily realized without deteriorating the inherent physical properties of the artificial tooth crystallized glass, and excellent aesthetics can be exhibited.

Therefore, the crystallized glass produced by the coloring method of the crystallized glass for artificial teeth according to the present invention can exhibit excellent physical properties and aesthetics due to uniform color reproduction, and thus is suitable for use as a material for coping or crowns of artificial teeth.

At this time, the crystallized glass for artificial teeth according to the present invention is colored by any one of the colors A, B, C, and D of the Vita shade guide, which is a tooth color reference chart, ₂ Si ₃ O ₁₀ crystal phase is a column phase, and an additional phase may include a MgAl ₂ O ₄ crystal phase and a ZrO ₂ or TiO ₂ crystal phase. Here, the columnar phase means a crystalline phase having the highest peak intensity in the x-ray diffraction phase analysis among the crystalline phases in the crystallized glass.

Further, the crystallized glass according to the present invention may exhibit a flexural strength of 300 MPa or more, a fracture toughness of 2.5 MPa · m ^1/2 , a Vickers hardness of 6.0 GPa or more, and a visible light transmittance of 35% or more based on 1 mm in terms of mechanical properties.

Example

Hereinafter, a preferred embodiment will be described in order to facilitate understanding of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

1. Preparation of specimens

Colored samples of crystallized glass for artificial teeth according to Examples 1 to 24 and Comparative Example 1 were prepared in the following manner. At this time, the test piece according to Comparative Example 1 was prepared in the same manner as in Example 1, except that no coloring additive was added.

First, the glass raw material powder and the coloring additive were put into a ball jar according to Examples 1 to 24. Table 1 shows specific types and compositions of glass raw materials and coloring additives.

[Table 1]

Then, the resultant was put into a melting furnace, heated to 1580 캜 at a heating rate of 10 캜 / minute, firstly melted for 180 minutes, and then subjected to water quenching To form a primary glass in a carved state. Thereafter, it was dried at 120 DEG C for 30 minutes.

Next, the dried specimens were pulverized to a size of 1 mm or less.

Next, the second milled resultant was put into a melting furnace, heated to 1580 ° C at a heating rate of 10 ° C / minute, secondarily melted for 180 minutes, and then melted into a graphite mold for molding.

Next, the graphite mold was charged into an electric furnace preheated to 790 占 폚, maintained for 1 hour and then cooled to room temperature to form secondary glass.

Next, the secondary glass was heated at a heating rate of 5 DEG C / minute, maintained at the crystallization heat treatment temperature condition of Table 1 for 180 minutes, and then cooled to room temperature to prepare a crystallized glass colored sample for artificial teeth.

2. Characterization

Table 2 shows the measurement results of the mechanical properties of the crystallized glass coloring test piece for artificial teeth according to Examples 1 to 24 and Comparative Example 1. [

[Table 2]

Referring to Table 2, in the case of the specimens according to Examples 1 to 24, the flexural strength was 300 MPa or more, the fracture toughness was 2.5 MPa · m ^1/2 , the Vickers hardness was 6 GPa or more, and the visible light transmittance was 35% Able to know.

Particularly, in the case of the specimens according to Examples 1 to 24, it was confirmed that there was no significant difference in mechanical properties even when compared with Comparative Example 1 in which no color additive was added.

Fig. 3 is a photograph showing crystallized glass colored by the method according to Examples 1 to 8, Fig. 4 is a photograph showing crystallized glass colored by the method according to Examples 9 to 16, Fig. 5 is a photograph showing Examples 17 to 24 Are the photographs showing the crystallized glass colored by the method according to FIG.

As shown in Figs. 3 (a) to 3 (h), 4 (i) to 4 (p) and 5 It can be confirmed that various colors were formed depending on the kind and content of the additive.

Therefore, when a small amount of a coloring additive is directly added to realize the colors of the A, B, C, and D series of the Vita shade guide as a tooth color reference chart, the properties of the crystallized glass for artificial teeth are deteriorated It is easy to realize a uniform color and an excellent aesthetic effect can be obtained.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

S110: Coloring mixture forming step
S120: primary pulverization step
S130: primary glass forming step
S140: Secondary pulverization step
S150: Secondary glass forming step
S160: crystallization heat treatment step

Claims (11)

(a) mixing a coloring additive with a glass raw material comprising SiO ₂ , MgO, Al ₂ O ₃ and a nucleation seed to form a colored mixture;
(b) firstly pulverizing the colored mixture;
(c) forming a primary glass by first melting the primary milled color mixture and cooling the primary mixture;
(d) secondarily grinding the primary glass;
(e) secondarily melting the secondary milled primary glass and then cooling to form a secondary glass; And
(f) crystallizing and heat-treating the secondary glass, and cooling the crystallized glass.
The method according to claim 1,
In the step (a)
The glass raw material
Wherein the composition contains 45 to 47 wt% of SiO ₂ , 11 to 13 wt% of MgO, 31 to 33 wt% of Al ₂ O ₃ and 9 to 11 wt% of ZrO ₂ .
The method according to claim 1,
The nucleation seed
Coloring method of the crystallized glass for an artificial tooth, characterized in that ZrO ₂ or TiO _2.
The method according to claim 1,
In the step (a)
The coloring additive
At least one of Er ₂ O ₃ , Fe ₂ O ₃ , Cr ₂ O ₃ , Mn ₂ O ₃ , Ti ₂ O ₃ , V ₂ O ₃ , Co ₂ O ₃ , CeO ₂ and Y ₂ O ₃ Characterized in that the crystallized glass for artificial teeth is colored.
The method according to claim 1,
In the step (a)
The coloring additive
0.0005 to 0.003 mol% based on the total weight of the composition.
The method according to claim 1,
The primary milling is performed by ball milling,
Wherein the secondary pulverization is carried out in a mortar.
The method according to claim 1,
In the step (e)
Wherein the molten material is cooled in a state that the molten material is put in a mold after the secondary melting.
The method according to claim 1,
The cooling in the step (c) is performed in a water quenching manner,
Wherein the cooling in steps (e) and (f) is performed in a cooling-in-furnace manner.
The method according to claim 1,
In the step (f)
The crystallization heat treatment
Is carried out at 1,000 to 1,100 ° C.
A method of coloring a crystallized glass for artificial teeth according to any one of claims 1 to 9, comprising the steps of: preparing a coloring glass for an artificial tooth according to any one of colors A, B, C, and D of a Vita shade guide A crystallized glass for artificial teeth,
Wherein the MgAl ₂ Si ₃ O ₁₀ crystal phase is a columnar phase and the additional phase comprises a MgAl ₂ O ₄ crystal phase and a ZrO ₂ or TiO ₂ crystal phase.
11. The method of claim 10,
The above-mentioned crystallized glass for artificial teeth
A flexural strength of 300 MPa or more, a fracture toughness of 2.5 MPa · m ^1/2 , a Vickers hardness of 6.0 GPa or more, and a visible light transmittance of 35% or more based on a 1 mm thickness.

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