KR101395862B1 - GLASS COMPOSITIONS and GLASS-INFILTRATED CERAMIC for DENTAL PROSTHETICS - Google Patents

Abstract

The infiltration glass contains 35 to 45 wt% of lanthanum oxide (La ₂ O ₃ ), 14 to 24 wt% of silica (SiO ₂ ), 14 to 24 wt% of alumina (Al ₂ O ₃ ) (B ₂ O ₃ ), 2 to 6 wt% of sodium oxide (NaO), 1 to 3 wt% of calcium oxide (CaO), and 2.5 wt% or less of magnesium oxide (MgO). When magnesium oxide (MgO) is included, the glass is more effectively penetrated into the ceramic core, improving the mechanical properties and durability of dental floss replication.

Description

TECHNICAL FIELD [0001] The present invention relates to a dental glass composition and a glass infiltration ceramic restoration material,

The present invention relates to a dental restorative material prepared by infiltrating a glass composition into a ceramic core. More particularly, the present invention relates to a new dental glass composition to which magnesium oxide is added to obtain a restoration having enhanced durability by improving the penetration into a ceramic core, a dental restoration made using the composition, will be.

When restoring a damaged tooth, it is important to choose the right material with a variety of considerations. Although the physical properties of alloys, amalgam, composite resins and ceramics used in dental restoration are continuously improving, ideal dental restorative materials that satisfy both aesthetic, functional and biocompatibility have not been proposed yet .

Dental alloys with superior mechanical properties have low aesthetics and are difficult to use in the anterior region. There is also a risk of biohazardment due to the elution of metal ions. Dental composite resins have excellent esthetics but somewhat lack of mechanical strength, and unreacted monomers There is a risk of biohazard by the outflow of water. Dental ceramics with superior aesthetics and biocompatibility have been increasing in use due to the introduction of new materials with dramatically improved properties. Korean Patent Laid-Open Publication No. 10-2004-0106889 discloses a glass-ceramic material for an artificial hole having improved mechanical properties and aesthetics, and a method for manufacturing the same.

The In-Ceram system manufacturer (Vita Zahnfabrik, Bad Sackingen, Germany) has attempted to obtain improved mechanical strength by using a new technique, slip-casting process, using alumina particles, which are crystalline phases, to form basic structures. Introduced in 1989, In-Ceram Alumina is the first all-ceramic restoration used in anterior-section 3-unit FPDs. In this method, densely condensed alumina (70-80 wt%) is sintered at 1,120 ° C for 10 hours to obtain a porous refractory structure. The lanthanum oxide-based glass is subjected to a secondary heat treatment at 1,100 ° C. for 4 hours to form a porous Structure to remove pores to limit the potential sites of crack propagation and increase strength. In addition, the residual compressive stress due to the difference in thermal expansion coefficient between alumina and glass can further improve the strength. In order to improve the aesthetics of the structure, the firing process is performed with feldspar porcelain. In this two step process, excellent mechanical properties such as flexural strength of 236-600 ㎫ and fracture toughness of 3.1-4.6 ㎫ m ^0.5 can be obtained.

There have been many attempts to develop similar ceramic products with excellent properties of the In-Ceram Alumina system, but there is no commercialization yet. In the case of In-Ceram Alumina, there is a problem that the sintering time and the glass penetration time of the alumina slurry are excessively consumed in the process of manufacturing the actual prosthesis.

It is required to develop a dental glass infiltration alumina which can improve not only the physical properties of the existing In-Ceram Alumina system but also the operability.

An object of the present invention is to provide a new composition of dental lanthanum-based glass containing an appropriate amount of magnesium oxide (MgO) so as to improve operability without decreasing the physical properties of the In-Ceram Alumina system and to increase viscosity and penetration There is a purpose.

Another object of the present invention is to provide a glass penetration restoration material having excellent physical properties and operability by using the dental lanthanum-based glass described above.

The present invention provides a glass composition for impregnating ceramics and a glass ceramic dental material using the same.

Hereinafter, the present invention will be described in more detail. The technical terms used in the present invention have the meanings understood by those of ordinary skill in the art to which the present invention belongs, Description of functions and configurations is omitted.

The present invention relates to a glass composition for penetration of a dental restorative material, which comprises at least one of lanthanum oxide (La2O3), silica (SiO2), alumina (Al2O3), boron oxide (B2O3), sodium oxide (NaO), calcium oxide (CaO) ). ≪ / RTI >

The glass composition for penetration of the dental restoration according to the present invention comprises not more than 2.5% by weight of magnesium oxide. Magnesium oxide improves the penetration of the glass composition into the ceramic core.

The glass composition for penetration of the dental restoration according to the present invention comprises lanthanum oxide in the range of 35 to 45 wt%. Depending on the composition of the lanthanum oxide, the aesthetics and the mechanical strength change.

Lanthanum oxides Dental glass composition for the penetration of the restorative material is from 35 to 45% by weight according to the present invention (La ₂ O _3), 14 to 24% by weight of silica (SiO _2), 14 to 24% by weight of alumina (Al ₂ O ₃ ), 12 to 21% by weight of boron oxide (B ₂ O ₃ ), 2 to 6% by weight of sodium oxide (NaO) and 1 to 3% by weight of calcium oxide (CaO). And 2.5% by weight or less of magnesium oxide (MgO).

The present invention relates to a dental restorative material for the ceramic core, the ceramic core of lanthanum oxide to the inside from the surface of a ceramic core to the (La ₂ O _3), silica (SiO _2), alumina (Al ₂ O _3), boron oxide (B ₂ O ₃ ), sodium oxide (NaO), calcium oxide (CaO), and magnesium oxide (MgO) is infiltrated into the denture restoration material.

The dental restoration according to the present invention includes that the material of the ceramic core is alumina.

The present invention relates to a method for producing a glass composition for penetration of a dental restoration material, comprising the steps of (a) laminating a lanthanum oxide (La ₂ O ₃ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ) (B) mixing the glass powder with a powder of sodium oxide (NaO), calcium oxide (CaO) and magnesium oxide (MgO), and (b) rapidly cooling the mixed powder to form a glass And a manufacturing method thereof.

The method for preparing a glass composition for penetration of a dental restoration according to the present invention comprises mixing oxide powders, followed by heat treatment at about 900 ° C for about 2 hours, cooling, and then mixing in a ball mill.

The method for preparing a glass composition for penetration of dental restorative materials according to the present invention includes a step of heat-treating the mixed oxide powder at about 1400 ° C for about 2 hours, followed by rapid cooling to form a glass structure.

(D) applying a glass for penetration to a ceramic core; (e) applying a penetrating glass to the inside of the ceramic core, And then heat treating the dental restorative material to infiltrate the dental restorative material.

The method of manufacturing a glass-penetrated dental restoration according to the present invention includes that the material of the ceramic core is alumina.

The method of manufacturing a glass-penetrated dental restoration according to the present invention includes that the glass composition for penetration is a powder of 50 탆 or less.

The method of manufacturing a glass-penetrated dental restoration according to the present invention includes heat treating the glass composition to penetrate the ceramic core at about 1150 ° C for about 25 minutes.

The glass composition for penetration according to the method of the present invention has a low viscosity at a high temperature to improve the penetration into the ceramic and the thermal expansion coefficient to increase the penetration into the ceramic to form a stress field to increase the fracture strength of the ceramic, The durability of the restoration is improved.

1 shows the process of preparing the glass composition according to the present invention
2 Manufacturing process of ceramic core according to the present invention
Figure 3: Manufacturing process of the ceramic restoration according to the present invention
4 shows the XRD pattern of the glass composition according to the present invention.
5 is a cross-sectional photograph of alumina impregnated with the glass composition according to the present invention

Hereinafter, a method of manufacturing a glass for penetration according to an embodiment of the present invention will be described in detail. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

Hereinafter, the infiltration glass containing magnesium oxide of the present invention and its production method will be described in detail.

Glass infiltrated alumina according to embodiments of the present invention is used in making dental restorations to replace hard tissue, and includes lanthanum oxide, silica, alumina, sodium oxide, boron oxide, calcium oxide, and magnesia.

The infiltration glass for include about 35 to 45% by weight of lanthanum oxide (La ₂ O _3). When the composition is more than 35% by weight, the transparency is improved to improve the esthetics, which is an advantage of the dental ceramics. When the content is less than 45% by weight, the viscosity of the lanthanum oxide is decreased and the possibility of brittleness is lowered.

The infiltration glass for include about 14 to 24% of silica (SiO ₂₎ and alumina (Al ₂ O ₃₎ by weight. When silica and alumina are contained in an amount of 14% by weight or more, the glass is easily formed and the viscosity is decreased, and the physical properties of the glass are optimally preferable at 24% by weight or less.

The penetration glass comprises about 2 to 6 weight percent sodium oxide (NaO). When the amount of sodium oxide is 2% by weight or more, the melting temperature of the glass is low and the viscosity at low temperature is low, and the physical properties of the glass are optimally preferable at less than 6% by weight.

The penetration glass contains about 1 to 3% by weight of calcium oxide (CaO). When the amount of calcium oxide is 1% by weight or more, the melting temperature of the glass is low and the viscosity at a high temperature is low. When the content of calcium oxide is less than 3% by weight, the physical properties of the glass are optimum.

The infiltration glass comprises about 2.5% by weight or less of magnesium oxide (MgO). Magnesium oxide can significantly increase the physical properties of the dental glass penetration ceramic restorative material by lowering the high temperature viscosity and increasing the penetration of the glass into the ceramic core.

A manufacturing process of the infiltration glass comprising the above-described main constituent components is shown in a flow chart in Fig. The lanthanum glass for penetration used in dental alumina composites is composed of high purity lanthanum oxide (La ₂ O ₃ ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), sodium oxide ₂ O), calcium oxide (CaO), and magnesia (MgO) powder are precisely weighed (0.1 mg accuracy) and mixed by pouring and pouring, followed by uniform mixing in a ball mill for 24 hours. The mixed powders were firstly heated in an electric furnace at 900 ° C for 2 hours, cooled, and mixed again in a ball mill for 24 hours. The uniformly mixed powders are melted by heating in an electric furnace at 1,400 ℃ for 2 hours and then quenched into glass pieces, finely pulverized with a planetary mill, and powders of 50 ㎛ or less are selected by a sieving machine to prepare glass powders. 2 is an XRD pattern of the glass powder produced.

The manufacturing process of the powder for ceramic cores is shown in Fig. When the ceramic core is made of alumina, alumina powder having an average particle size of 1-3 μm and a purity of 99.99% and alumina powder having an average particle size of 2-4 μm are mixed at a weight ratio of 3: 7. The mixed powder is put into a high purity alumina pod, and the mixture is uniformly mixed by performing a dry stirring in a ball mill for 2 hours or more. 30 wt% of distilled water was added to the dry mixed powder and wet mixed in a ball mill for 10 hours to prepare an alumina slurry for a core. The slurry was dried in a drier for 3 days and then pulverized in a ball mill to prepare a powder.

The manufacturing process of the glass penetration ceramic restoration material is shown in Fig. When the ceramic core is made of alumina, the alumina slurry for the core is molded with a brush, or the dried powder is put into a mold and molded under a load of 2,000 kgf. The formed slurry is dried for about 3 minutes in a ceramics baking furnace at 500 ° C and sintered. Heated to 1,150 ° C at a rate of 60 ° C / min, maintained at 1,150 ° C for 15 minutes, and then cooled to 500 ° C for 5 minutes to prepare a first sintered alumina core.

The glass powder for penetration is mixed with distilled water on the surface of the first sintered alumina core to a thickness of about 2 mm and then dried at 500 ° C. for about 5 minutes in the ceramic fire extinguishing furnace. The glass is heated to 1,150 ° C at a heating rate of 80 ° C / min to penetrate the alumina core, then held at 1,150 ° C for 25 minutes and cooled to 500 ° C for 5 minutes. The glass penetration alumina surface is polished with SiC abrasive paper to remove excess residual glass phase to produce glass penetration alumina.

The magnesium oxide, which is one of the starting oxides in the present invention, lowers the high-temperature viscosity of the glass and facilitates penetration into the ceramic core, thereby improving the physical properties of the dental glass-infiltrated alumina.

Hereinafter, the present invention will be described in detail with reference to specific examples (Example 1-4) of a glass composition synthesized by controlling the fraction of magnesium oxide and a restoration material prepared by infiltrating the glass composition into an alumina core with conventional In-ceram alumina .

Lanthanum oxide of 39.5% by weight of (La ₂ O _3), of 19% by weight silica (SiO ₂₎ and alumina (Al ₂ O _3), 16% by weight of boron oxide _{(B 2 O 3), 4} % by weight of sodium oxide (NaO), 2 wt% of calcium oxide (CaO), and 0.5 wt% of magnesium oxide (MgO) to prepare a glass composition and penetrate the alumina core to prepare a glass penetration alumina restoration.

Magnesium oxide (MgO) was added to the final glass so as to have a fraction of 1.0 wt%, and a glass composition was prepared in the same manner as in Example 1.

Magnesium oxide (MgO) was added to the final glass so as to have a fraction of 1.5 wt%, and a glass composition was prepared in the same manner as in Example 1.

Magnesium oxide (MgO) was added to the final glass so as to have a fraction of 2.0 wt%, and a glass composition was prepared in the same manner as in Example 1.

<Comparative Example>

An insolam glass not containing magnesium oxide was used.

Table 1 shows the kinds and contents of the components used in the production of the glass compositions of Examples 1-4 and Comparative Examples.

Groups La ₂ O ₃ SiO ₂ Al ₂ O ₃ B ₂ O ₃ Na ₂ O CaO MgO TiO ₂ CeO ₂ Fe ₂ O ₃ Comparative Example
(weight%) 41 16.3 15.6 15.4 * 1.95 * 4.75 4 0.73 Example-1
(weight%) 39.5 19.0 19.0 16.0 4.0 2.0 0.5 * * * Example-2
(weight%) 39.0 19.0 19.0 16.0 4.0 2.0 1.0 * * * Example-3
(weight%) 38.5 19.0 19.0 16.0 4.0 2.0 1.5 * * * Example-4
(weight%) 38.0 19.0 19.0 16.0 4.0 2.0 2.0 * * *

Penetration Glass  Property evaluation

The physical properties of the penetrating glass thus prepared were evaluated. The melting range, thermal expansion coefficient and high temperature viscosity of the glass prepared according to the above Examples and Comparative Examples were compared and evaluated. The results are shown in Table 2 below.

Comparative Example Example 1 Example 2 Example 3 Example 4 Coefficient of thermal expansion
(ppm / DEG C) 7.4 7.46 ± 0.35 7.64 ± 0.26 7.83 + 0.11 7.91 ± 0.28 High temperature viscosity
(1200 ° C, poise) 1.20 1.09 0.31 0.54 0.24 Melting temperature
Range (℃) 826 - 1115 822-1143 824-1133 823-1127 825-1120

Referring to Table 2, it can be seen that as the fraction of magnesium oxide increases, the thermal expansion coefficient increases and the viscosity decreases. As the coefficient of thermal expansion increases, it penetrates into alumina and solidifies, and then the stress field is formed more and the physical properties are improved. Also, if the viscosity at high temperature is reduced, it becomes easier to penetrate the alumina, and the depth of the glass is deepened, which is a factor for improving the mechanical properties of the dental restorative material.

5 is a cross-sectional photograph of the glass penetration alumina of Example 2. Fig. A glass region, a glass penetration alumina region and an alumina core region are sequentially formed from the left side of the photograph. The penetration depth of the glass composition was determined by measuring the distance between the glass / glass penetration alumina interface and the glass penetration alumina / alumina core interface.

Samples for measuring the penetration depth of the glass composition into the alumina core were prepared in the following manner. An appropriate amount of alumina powder was put into a cylindrical metal mold having a diameter of 10 mm, and a specimen was formed by applying a load of 2,000 kgf, followed by drying in a ceramic furnace at 500 ° C. for about 3 minutes. The dried specimens were heated to 1,150 ° C at a rate of 60 ° C / min, maintained at 1,150 ° C for 15 minutes, and then cooled to 500 ° C for 5 minutes to prepare first sintered alumina core specimens. The glass powder for penetration was mixed with distilled water and applied to a thickness of about 2 mm on the first sintered alumina core. After heating for 5 minutes at 500 ° C in a ceramic furnace, it was heated to 1,150 ° C at a heating rate of 80 ° C / min, held at 1,150 ° C for 25 minutes and then cooled to 500 ° C for 5 minutes to permeate the glass into the alumina core. The surface of the glass penetration alumina specimen was polished with SiC abrasive paper to remove excess residual glass phase to prepare a glass penetration alumina specimen. The prepared specimen was bisected with a low speed diamond saw and embedded with acrylic resin, and then the surface was treated with # 300-4,000 SiC abrasive paper, diamond abrasive (6 ㎛, 3 ㎛ and 1 ㎛) and alumina abrasive (0.03 ㎛) After polishing, cross-sectional images of the specimens were obtained using a stereomicroscope (SMZ-U, Nikon, Japan) and Image Analyzer program. From this image, the penetration thickness of the molten glass penetrating into the alumina core from the surface was measured. The depth of penetration was measured in five parts of the specimen, and the average value was obtained by measuring five specimens per each experimental group. Table 3 shows the results of measuring the depth of infiltration of the glass into the alumina core (infiltration depth) according to the fraction of magnesium oxide.

Comparative Example
In-Cceram Alumina Example 1 Example 2 Example 3 Example 4 Penetration depth
(탆) 430 ± 73 1,101 ± 24 1,128 ± 21 1,168 ± 18 1,214 ± 22

Referring to Table 3, as the fraction of magnesium oxide increases, the depth of penetration of the glass increases, which is consistent with the expected result from the decrease in the high temperature viscosity shown in Table 2. Therefore, magnesium oxide is added, and the mechanical properties of the final alumina restoration material can be improved as the fraction increases.

Table 4 shows the result of evaluating the flexural strength of the glass penetration alumina ceramic.

Group
Money Comparative Example Example-1 Example-2 Example-3 Example-4 ? _f (0.5) 366.2 558.1 554.2 597.0 553.1 m  8.087  5.258  7.698  8.766  6.447 σ ₀ 383.2 598.5 581.2 622.5 585.5 r ² 0.965  0.930  0.937  0.888 0.896 σ _f (avr) 364.2 ^b 559.0 ^a 547.0 ^a 593.5 ^a 556.7 ^a SD  47.6 103.5  79.0  70.4  79.6 N  10  18  18  18  18

note: σ _f (0.5) = median fracture strength (P _f = 50.0%) in MPa

      m = Weibull modulus

σ ₀ = characteristic strength (P _f = 63.2%) in MPa

r ² = Weibull distribution regression coefficient squared

? _f (avr) = mean fracture strength in MPa

      SD = standard deviation

N = number of samples

Referring to Table 4, the flexural strength is one of the measures for the quality of dental ceramics. When magnesium oxide is added, the bending strength increases drastically, and as the fraction of magnesium oxide increases, the bending strength increases.

As described above, by adding magnesium to the lanthanum oxide-based glass as described in the examples of the present invention, the thermal expansion coefficient increases, the high-temperature viscosity decreases, the depth of penetration into the ceramic restoration increases, and the strength of the ceramic restoration becomes Respectively.

σ _f (0.5) = median fracture strength (P _f = 50.0%) in MPa
m = Weibull modulus
σ ₀ = characteristic strength (P _f = 63.2%) in MPa
r ² = Weibull distribution regression coefficient squared
? _f (avr) = mean fracture strength in MPa
SD = standard deviation
N = number of samples

Claims (16)

delete delete delete delete delete delete A method of manufacturing a glass composition for penetration of a ceramic core of a dental restorative material,
(a) 35 to 45 wt% of lanthanum oxide (La2O3), 14 to 24 wt% of silica (SiO2), 14 to 24 wt% of alumina (Al2O3), 12 to 21 wt% of boron oxide (Na2O), 1 to 3 weight% calcium oxide (CaO), and 0.5 to 2.5 weight% magnesium oxide (MgO) powder; And
(b) melting the mixed powder and then rapidly cooling the glass to form a glass.
[7] The method according to claim 7, further comprising, after the step (a), further comprising the step of heat-treating the mixed powder (a-1) at 900 ° C for 2 hours, .
[7] The method of claim 7, wherein the melting process of step (b) is performed by heat treatment at 1400 ° C for 2 hours.
delete delete delete A method of making a dental restorative material impregnated with glass,
(c) preparing an infiltration glass by the method of claim 7;
(d) applying the penetrating glass to the ceramic core; And
(e) heat treating the penetrating glass to penetrate the ceramic core. &lt; RTI ID = 0.0 &gt; 8. &lt; / RTI &gt;
14. The method of claim 13, wherein the material of the ceramic core is alumina.
delete [14] The method of claim 13, wherein the heat treatment in step (e) is performed at 1150 [deg.] C for 25 minutes.

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