KR102532578B1 - Phosphoric acid-calcium based glass ceramic block and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a calcium phosphate-based glass ceramic block that can be processed by a CAD/CAM (computer-aided design/computer-aided manufacturing) processing method and a method for manufacturing the calcium phosphate-based glass ceramic block. The calcium phosphate-based glass-ceramic block according to the method has excellent processability for dental restorations by CAD/CAM processing, enables precise processing, has density and thermal conductivity similar to that of teeth, and has excellent biocompatibility and aesthetics. Since it has mechanical properties applicable to the CAM processing method, it can be processed using the CAD/CAM processing method, so the processing time of dental restorations can be reduced.

Description

Phosphoric acid-calcium based glass ceramic block and manufacturing method thereof}

The present invention relates to a calcium phosphate-based glass ceramic block and a method for manufacturing the calcium phosphate-based glass ceramic block.

Dental restoration is a procedure for restoring teeth severely damaged by dental caries or trauma. In other words, it is a method of manufacturing a dental restoration to which a standard shape is applied to restore a damaged tooth and applying it to the tooth. Dental restorations, which are made of metal or resin, have been used until now, but they do not satisfy strength and aesthetics at the same time, and discoloration and fracture occur due to a decrease in color stability and strength. there is.

In particular, noble metal alloys such as gold (Au) alloys have been widely used for dental restorations such as veneers, inlays, onlays, stumps, and crowns. However, precious metal alloys such as gold (Au) alloys are expensive, and recently, the value of gold (Au) has risen sharply according to the global trend, and accordingly, the manufacturing cost of noble metal alloy restorations is also on the trend of increasing very steeply. . In addition, since the precious metal alloy has a different color from natural teeth, many users are reluctant to use it for aesthetic reasons.

Among these dental restorative materials, ceramic materials have advantages such as excellent compressive strength, abrasion resistance, aesthetics, and chemical stability. has In order to compensate for these disadvantages, a metal-reinforced porcelain-metal crown was introduced at the lower part of the feldspar-based porcelain, but problems such as exposure of metal in the marginal area, diffusion of metal oxide in the gingival area, deterioration in aesthetics, and allergic reaction due to metal seemed In recent years, as the manufacturing technology of ceramic materials has greatly advanced, a number of materials for all-porcelain materials have been introduced into dental clinics. In addition, in terms of enhancing aesthetics, marginal fit, and mechanical strength, glass-ceramic is first heat treated and then CAD / CAM (CAD / CAM) is used. After machining with CAM), attention has been focused on how to increase the strength by performing secondary heat treatment. That is, in performing the two-step heat treatment, each heat treatment was intermittently performed.

As a ceramic material for all ceramic materials, glass-ceramic, an alumina-based ceramic material introduced earlier, is a ceramic material with improved mechanical strength by dispersing and strengthening alumina particles, which are high-strength ceramics, in glass. Glass-ceramic, which is an alumina-based porcelain, has improved strength as the content of alumina increases, but has a disadvantage in that aesthetics deteriorate due to reduced transparency.

Therefore, in order to compensate for the disadvantages of glass-ceramic, after making a glass block with a target composition, a meta silicate crystal phase having good processability is generated by heat treatment to make a semi-finished product. A method of processing it with CAD/CAM to suit the shape of the user's teeth and then finally making it into lithium disilicate glass-ceramic with excellent mechanical strength is used. This CAD/CAM processing method can improve accuracy and marginal fit, and has the advantages of a more accurate manufacturing process, low porosity, excellent marginal fit, and high strength and Weibull distribution coefficient compared to traditional sintering methods. seemed

In this regard, Japanese Patent Registration No. 6661828 discloses a lithium silicate glass ceramic exclusively for dental moldings, including lithium disilicate and lithium aluminum silicate.

In addition, U.S. Patent Publication No. 2015/0104655 discloses a composition comprising lithium silicate, lithium metasilicate, lithium phosphate, cristobalite, toridimito, quartz or lithia pyroxene as a crystal phase, depending on the composition and temperature treatment selected for crystallization. Glass ceramics are disclosed.

However, glass-ceramics containing lithium disilicate crystals are too hard to machine with CAD/CAMs with diamond tools.

Japanese Patent Registration No. 6661828 US Patent Publication No. 2015/0104655

An object of the present invention is to provide a calcium phosphate-based glass ceramic block that can be processed by a CAD/CAM (computer-aided design/computer-aided manufacturing) processing method and a method for manufacturing the calcium phosphate-based glass ceramic block.

In order to solve the above problems,

In one embodiment, the present invention

10 to 50 mol% Al ₂ O ₃ , 20 to 50 mol% SiO ₂ , 3 to 10 mol% Na ₂ O, 3 to 10 mol% MgO, 3 to 10 mol% P ₂ O ₅ , and 5 to 20 mol% CaO It provides a phosphate-calcium based glass ceramic block containing %.

Fe ₂ O ₃ 0.001 to 5 mol% may be included as an auxiliary component.

It may include 0.001 to 5 mol% of Cr ₂ O ₃ as an auxiliary component.

TiO ₂ 0.001 to 5 mol% may be included as an auxiliary component.

It may contain 0.001 to 5 mol% of CoO as an auxiliary component.

NiO 0.001 to 5 mol% may be included as an auxiliary component.

In addition, in one embodiment of the present invention,

The phosphate-calcium-based glass ceramic block contains 10 to 50 mol% of Al ₂ O ₃ , 20 to 50 mol% of SiO ₂ , 3 to 10 mol% of Na ₂ O, 3 to 10 mol% of MgO, and 3 to 10 mol of P ₂ O ₅ %, and mixing Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , CaCO ₃ as raw materials to contain 5 to 20 mol% of CaO; forming a frit by subjecting the raw material mixture to a first heat treatment so as to be melted and then quenching; crushing and softening the frit; Molding the softened product into a block shape and slowly cooling it; and forming a glass ceramic block by subjecting the molded product to a second heat treatment for crystallization.

The raw material may include 0.001 to 5 mol% of Fe ₂ O ₃ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of Cr ₂ O ₃ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of TiO ₂ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of CoO as an auxiliary component.

The raw material may include 0.001 to 5 mol% of NiO as an auxiliary component.

The first heat treatment may include raising and maintaining a temperature at a first temperature of 300 to 600° C.; Raising and maintaining the temperature at a second temperature of 700 to 1100 ° C; and melting the raw material mixture by raising and maintaining the temperature at a third temperature of 1350 to 1550 °C, and the second heat treatment may be performed at a temperature of 620 to 780 °C.

The phosphate-calcium-based glass ceramic block according to the present invention has a composition of P ₂ O ₅ -CaO as a main component and additives for color expression and crystallization induction are added to allow CAD/CAM processing through a heat treatment process after manufacturing the glass ceramic block. A calcium phosphate-based glass ceramic block may be prepared.

In addition, the phosphate-calcium-based glass ceramic block according to the present invention has excellent processability for dental restorations by the CAD/CAM processing method, can be precisely processed, has density and thermal conductivity similar to that of teeth, and has biocompatibility and aesthetics. It is excellent and has mechanical properties applicable to the CAD/CAM processing method, so it can be processed using the CAD/CAM processing method, so the processing time of dental restorations can be shortened.

Unlike conventional metal and resin crowns, the phosphate-calcium-based glass ceramic block according to the present invention is aesthetically superior as a ceramic, has excellent biocompatibility, and has high strength and toughness. In addition, since the thermal conductivity is similar to that of natural teeth, tooth decay can be suppressed, and light transmittance and color similar to natural teeth are expressed, so that the sense of difference with natural teeth is small, and bacteria such as streptococcus mutans (Streptococcus mutans) The propagation of the teeth is also suppressed, and the wear of the natural teeth is suppressed because the strength and hardness are very similar to those of natural teeth.

1 is a diagram illustrating a first heat treatment process for melting raw materials.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the term "comprises" or "has" is intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In the present invention, the CAD/CAM (Computer-aided-design/Computer-aided-manufacture) term is a device with the highest penetration and marketability among digital dental medical devices, It refers to a method of fabricating a restoration by designing a restoration using computer software using information about the restoration, transmitting the information of the designed restoration to a milling machine, and cutting a block.

Hereinafter, the present invention will be described in detail.

Since computer-aided design (CAD) and computer-aided manufac\-turing (CAM) methods were introduced in the process of manufacturing dental restorations, dental treatment and dental prosthesis manufacturing have rapidly progressed. It is becoming a universal and essential option in the dental industry, and along with this, dental ceramic materials that can be processed with CAD/CAM systems are also being developed at the same time.

Therefore, the present invention is a phosphate-calcium-based glass ceramic block capable of CAD/CAM processing through a heat treatment process after manufacturing a glass ceramic block by adding auxiliary components for color expression and crystallization induction with a composition of P ₂ O ₅ -CaO as a main component. And it provides a manufacturing method thereof.

Specifically, the phosphate-calcium-based glass ceramic block according to the present invention contains 10 to 50 mol% of Al ₂ O ₃ , 20 to 50 mol% of SiO ₂ , 3 to 10 mol% of Na ₂ O , 3 to 10 mol% of MgO, and P ₂ O ₅ 3 to 10 mol%, and CaO 5 to 20 mol%.

The P ₂ O ₅ is a material forming a glass matrix, and contains a phosphorus (P) component, which is contained in a large amount in natural teeth, and exhibits light transmittance and color similar to natural teeth, thereby reducing the sense of difference with natural teeth. It also plays a role in inhibiting the growth of bacteria such as streptococcus mutans. P ₂ O ₅ is preferably contained in an amount of 3 to 10 mol% in the phosphate-calcium-based glass ceramic block. When the content of P ₂ O ₅ is less than 3 mol%, the effect of suppressing bacterial growth and light transmittance similar to that of natural teeth are obtained. and when the effect of expressing color is weak and the content of P ₂ O ₅ exceeds 10 mol%, the strength of the phosphate-calcium-based glass ceramic block may decrease.

The CaO contains a calcium (Ca) component, which is contained in a large amount in natural teeth, and plays a role of helping to express light transmittance and color similar to natural teeth. CaO is preferably contained in an amount of 5 to 20 mol% in the phosphate-calcium-based glass ceramic block. If the content of CaO is less than 5 mol%, there is a limit in expressing light transmittance and color similar to natural teeth, and the CaO content is If it exceeds 20 mol%, the strength of the phosphate-calcium-based glass ceramic block may decrease.

The Al ₂ O ₃ acts as a crystalline seed in the glass matrix, thereby increasing the hardness and strength of the calcium phosphate-based glass ceramic block to improve durability. Al ₂ O ₃ increases the strength of the phosphate-calcium-based glass ceramic block because a strong compressive force acts on the glass due to the difference between the matrix and thermal expansion coefficient of the glass phase. Al ₂ O ₃ is preferably contained in an amount of 10 to 50 mol% in the phosphate-calcium-based glass ceramic block. When the content of Al ₂ O ₃ is less than 10 mol%, the hardness and strength of the phosphate-calcium-based glass ceramic block are reduced. If the content of Al ₂ O ₃ exceeds 50 mol%, the hardness and strength of the phosphate-calcium-based glass-ceramic block are greater than that of natural teeth, which can wear down natural teeth when colliding with them. There is a problem.

The SiO ₂ is a material that forms a glass matrix, and has cohesive or adhesive strength, and serves as a binder for combining materials. When the raw materials are mixed and subjected to heat treatment, SiO ₂ is softened to form a glass phase and serves to bind the particles. SiO ₂ is preferably contained in an amount of 20 to 50 mol% in the phosphate-calcium-based glass ceramic block.

MgO serves to increase durability against thermal denaturation. MgO is preferably contained in an amount of 3 to 10 mol% in the phosphate-calcium based glass ceramic block.

The phosphate-calcium-based glass ceramic block according to the present invention may induce the expression and crystallization of an optimal artificial tooth color by further including an auxiliary component.

The phosphate-calcium-based glass ceramic block may include 0.001 to 5 mol% of Fe ₂ O ₃ as an auxiliary component.

The phosphate-calcium-based glass ceramic block may include 0.001 to 5 mol% of Cr ₂ O ₃ as an auxiliary component.

The phosphate-calcium-based glass ceramic block may include 0.001 to 5 mol% of TiO ₂ as an auxiliary component.

The phosphate-calcium-based glass ceramic block may include 0.001 to 5 mol% of CoO as an auxiliary component.

The phosphate-calcium-based glass ceramic block may include 0.001 to 5 mol% of NiO as an auxiliary component.

The Fe ₂ O ₃ is a reddish substance and is added to adjust the color of the phosphate-calcium-based glass ceramic block similarly to natural teeth, and also serves to improve mechanical properties of the phosphate-calcium-based glass ceramic block. The Fe ₂ O ₃ is preferably contained in an amount of 0.001 to 5 mol% in the phosphate-calcium-based glass ceramic block. When the content of Fe ₂ O ₃ is less than 0.001 mol%, the color of the phosphate-calcium-based glass ceramic block is changed. There is a limit to making it similar to natural teeth, and when the content of Fe ₂ O ₃ exceeds 5 mol%, the color of the phosphate-calcium-based glass ceramic block becomes red, which is different from the color of natural teeth. There may be.

The NiO plays a role of expressing light transmittance and color of the phosphate-calcium-based glass ceramic block, similar to natural teeth, and also serves to improve the mechanical properties of the phosphate-calcium-based glass ceramic block. NiO is preferably contained in an amount of 0.001 to 5 mol% in the phosphate-calcium based glass ceramic block.

The TiO ₂ is used as a nucleating agent when glass crystals are formed. TiO ₂ is known to be harmless to the human body due to its excellent biocompatibility. TiO ₂ is an effective component for expressing a similar color to biological teeth, and shows efficient performance in coloring during dental processing. TiO ₂ is preferably contained in an amount of 0.001 to 5 mol% in the calcium phosphate-based glass ceramic block.

Veneers, inlays, onlays, crowns, stumps, facets, artificial teeth, abutments, root structures using these calcium phosphate-based glass ceramic blocks A dental object such as the back can be selectively prepared.

In addition, in the present invention, the phosphate-calcium-based glass ceramic block contains 10 to 50 mol% of Al ₂ O ₃ , 20 to 50 mol% of SiO _{2 ,} 3 to 10 mol% of Na ₂ O, 3 to 10 mol% of MgO, and P ₂ O ₅ mixing Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , and CaCO ₃ as raw materials to contain 3 to 10 mol% and 5 to 20 mol% of CaO; forming a frit by subjecting the raw material mixture to a first heat treatment so as to be melted and then quenching; crushing and softening the frit; Molding the softened product into a block shape and slowly cooling it; and forming a glass ceramic block by subjecting the molded product to a second heat treatment for crystallization.

Hereinafter, a method for manufacturing a calcium phosphate-based glass ceramic block according to the present invention will be described.

In order to manufacture a calcium phosphate-based glass ceramic block, Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , CaCO ₃ , Fe ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , CoO, and NiO are weighed and prepared as starting materials. Considering that H ₃ PO ₄ is changed to P ₂ O ₅ in the subsequent heat treatment process, CaCO ₃ is changed to CaO in the subsequent heat treatment process, and Li ₂ CO ₃ is changed to Li ₂ O in the subsequent heat treatment process Each raw material was weighed, and the finally formed phosphate-calcium-based glass ceramic block contained 10 to 50 mol% of Al ₂ O ₃ , 20 to 50 mol% of SiO ₂ , 3 to 10 mol% of Na ₂ O , and 3 to 10 mol of MgO. %, 3 to 10 mol% of P ₂ O ₅ , and 5 to 20 mol% of CaO are weighed and prepared as starting materials. As an example, the starting materials are Al ₂ O ₃ 10 to 50 mol%, SiO ₂ 20 to 50 mol%, Na ₂ O 3 to 10 mol%, MgO 3 to 10 mol%, H ₃ PO ₄ 3 to 10 mol% , and CaCO ₃ 5 to 20 mol%.

The CaCO ₃ , which is one of the main constituents of the calcium phosphate-based glass ceramic block, is a source material for providing CaO, which is a component of the calcium phosphate-based glass ceramic block. The CaCO ₃ is changed into CaO by volatilizing carbon dioxide (CO 2 ) into a gas in a heat treatment process to be described later. CaO contains calcium (Ca), which is contained in a large amount in natural teeth, and plays a role of helping to express light transmittance and color similar to natural teeth. CaO is preferably contained in an amount of 5 to 20 mol% in the phosphate-calcium-based glass ceramic block. If the content of CaO is less than 5 mol%, there is a limit in expressing light transmittance and color similar to natural teeth, and the CaO content is If it exceeds 20 mol%, the strength of the phosphate-calcium-based glass ceramic block may decrease.

In addition, the H ₃ PO ₄ is a source material for providing P ₂ O ₅ , which is a component of the phosphate-calcium-based glass ceramic block. The H ₃ PO ₄ is changed to P ₂ O ₅ after a heat treatment process described later. P ₂ O ₅ is a material that forms a glass matrix, and contains phosphorus (P), which is contained in a large amount in natural teeth, and exhibits light transmittance and color similar to natural teeth to reduce the sense of difference with natural teeth. Not only does it play a role, but it also plays a role in inhibiting the growth of bacteria such as streptococcus mutans. P ₂ O ₅ is preferably contained in an amount of 3 to 10 mol% in the phosphate-calcium-based glass ceramic block. When the content of P ₂ O ₅ is less than 3 mol%, the effect of suppressing bacterial growth and light transmittance similar to that of natural teeth are obtained. and when the color expression effect is weak and the content of P2O5 exceeds 10 mol %, the strength of the calcium phosphate-based glass ceramic block may decrease.

The raw material may further include auxiliary components in order to induce crystallization and expression of an optimal artificial tooth color. The auxiliary component may be added to adjust the color of the phosphate-calcium-based glass ceramic block similar to natural teeth, promote crystallization, reduce thermal deformation, and improve mechanical properties such as strength during manufacture of the glass ceramic block. can make it

The raw material may include 0.001 to 5 mol% of Fe ₂ O ₃ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of Cr ₂ O ₃ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of TiO ₂ as an auxiliary component.

The raw material may include 0.001 to 5 mol% of CoO as an auxiliary component.

In addition, the raw material may include 0.001 to 5 mol% of NiO as an auxiliary component.

The auxiliary components Fe ₂ O ₃ , Cr ₂ O ₃ , When the content of TiO ₂ , CoO, or NiO is less than 0.001 mol%, there is a limit to making the color of the phosphate-calcium-based glass ceramic block similar to that of natural teeth, or there is a problem in that mechanical properties for future CAD/CAM processing are not met. When the content of the auxiliary raw material exceeds 5 mol%, the color may be different from that of natural teeth or the phosphate-calcium-based glass ceramic block may be too hard to process with CAD/CAM.

The raw materials are mixed and dried. The drying is preferably performed on a hot plate at a temperature of about 100 to 400° C. until liquid components are removed and only power remains.

The dried product is placed in a crucible made of a material such as platinum or alumina (Al ₂ O ₃ ), and the crucible is charged into a furnace to perform a first heat treatment so that the raw material is melted, followed by quenching to form a frit.

The first heat treatment may include raising and maintaining a temperature at a first temperature of 300 to 600° C.; Raising and maintaining the temperature at a second temperature of 700 to 1100 ° C; and melting the raw material mixture by raising and maintaining the temperature at a third temperature of 1,350 to 1,550 °C, and the second heat treatment may be performed at a temperature of 620 to 780 °C.

1 is a diagram illustrating a first heat treatment process for forming a calcium phosphate-based glass ceramic block according to the present invention. Hereinafter, the first heat treatment process will be described in more detail.

Referring to FIG. 1, a crucible containing raw materials is charged into a furnace. The temperature of the furnace is raised to a target first temperature using a heating means provided in the furnace and maintained for a predetermined time (eg, 10 minutes to 12 hours) (section t1 in FIG. 1). At this time, it is preferable that the temperature increase rate of the furnace is about 1 to 50° C./min. If the temperature increase rate of the furnace is too slow, it takes a long time to reduce productivity. Since stress may be applied, it is preferable to raise the temperature of the furnace at a heating rate within the above range. The first temperature is preferably about 300 to 600 °C. When maintained at the first temperature, organic components, which are impurities, may be burned and discharged to the outside, and carbon dioxide (CO ₂ ) gas may also be generated and discharged to the outside. If the organic components and carbon dioxide (CO ₂ ) remain, the physical properties of the frit obtained after the heat treatment may be poor, so the first temperature is maintained for a certain period of time.

It is raised from the first temperature to the second temperature and maintained for a predetermined time (eg, 10 minutes to 12 hours) (section t2 in FIG. 1). At this time, it is preferable that the heating rate of the furnace is about 1 to 50° C./min. The second temperature is preferably about 750 to 1,100 ℃. When maintained at the second temperature, carbon dioxide (CO ₂ ) gas is generated and can be discharged to the outside. If carbon dioxide (CO ₂ ) remains, pores may be formed and physical properties of the frit obtained after the heat treatment may be poor, so the second temperature is maintained for a predetermined time.

The temperature of the furnace is raised to the third temperature (target heat treatment temperature) and maintained for a predetermined time (eg, 10 minutes to 12 hours) (section t3 in FIG. 1). At this time, it is preferable that the heating rate of the furnace is about 1 to 50° C./min. When the temperature of the furnace reaches the target third temperature (eg, 1,350 to 1,550° C.), the dried product is melted by maintaining it at the third temperature (section t3 in FIG. 2 ).

The result of the heat treatment is rapidly cooled. The rapid cooling may use a pouring method in water. The internal strength of the frit is enhanced by rapidly cooling the resultant heat treatment.

The frit obtained by rapid cooling can be pulverized. The grinding may use various methods such as ball milling, jet mill, mortar grinding, jaw crusher, pulverizer, disk mill, and the like.

Referring to the ball milling process as an example, frit is loaded into a ball milling machine, and the raw material particles are mechanically pulverized and uniformly mixed by rotating at a constant speed using the ball milling machine. Balls used in ball milling can be ceramic balls such as zirconia (ZrO ₂ ) and alumina (Al ₂ O ₃ ), and all balls can be of the same size, or balls having two or more sizes can be used together. may be The ball size, milling time, and rotation speed per minute of the ball mill are adjusted to pulverize the target particle size. For example, considering the size of the frit particles, the ball size may be set in the range of about 1 to 30 mm, and the rotational speed of the ball mill may be set in the range of about 50 to 1000 rpm. Ball milling is performed for 10 minutes to 48 hours in consideration of the target particle size and the like. By ball milling, the frit is pulverized into finely sized particles and has a uniform particle size distribution.

The frit is placed in a crucible made of a material such as platinum or alumina (Al ₂ O ₃ ) and heated to soften the frit. Here, softening means that the raw material is changed to a material state having a viscosity of a liquid state rather than a solid state. The heating is preferably performed at a temperature of about 1,250 to 1,500° C. for a predetermined time (eg, 10 minutes to 12 hours). At this time, it is preferable that the temperature increase rate to the heating temperature for softening is about 1 to 50 ° C./min. If the temperature increase rate is too slow, it takes a long time to reduce productivity. Since thermal stress may be applied, it is preferable to raise the temperature at a temperature increase rate within the above range.

The softened result is poured into a block-shaped mold and molded. At this time, the mold is preferably maintained at a temperature of about 400 to 600 ℃ for molding. The holding temperature for the molding is preferably about 400 to 600° C. in consideration of diffusion of particles and necking between particles. If the holding temperature is too high, mechanical properties are deteriorated due to excessive growth of particles. If the holding temperature is too low, the mechanical properties of the block to be formed may not be good, so it is preferable to maintain the temperature in the above range.

The mold may be a mold made of graphite. The holding time for the molding is preferably about 10 minutes to 12 hours.

When molded in a block form, the temperature of the mold is gradually cooled (slowly cooled), and then the mold is removed from the mold.

A step of applying Li ₂ CO ₃ to the surface of the obtained molded product may be further included. For the application method, a method such as immersing the molded product in the Li ₂ CO ₃ solution, spraying the Li ₂ CO ₃ solution on the surface of the molded product by spraying, or applying the Li ₂ CO ₃ solution to the surface of the molded product with a brush or the like can be used. there is. The Li ₂ CO ₃ solution may be a solution obtained by adding Li ₂ CO ₃ to a solvent such as ethanol or methanol. The Li ₂ CO ₃ is changed into Li ₂ O by volatilizing carbon dioxide (CO ₂ ) into a gas in a heat treatment process for crystallization described later, and in the heat treatment process for crystallization described later, Li ₂ O is a molded product. It diffuses into the interior. By applying Li ₂ CO ₃ to the surface of the molded product, the mechanical properties of the phosphate-calcium-based glass-ceramic block can be improved, and the light-transmitting property and color of the phosphate-calcium-based glass-ceramic block can be expressed similarly to natural teeth. there is After applying Li ₂ CO ₃ to the surface of the molded product, a drying process is performed. The drying process is preferably performed at a temperature of about 40 to 150° C. for 10 minutes to 48 hours. The amount of Li ₂ CO ₃ applied to the surface of the molded product is preferably about 0.0001 to 3 parts by weight based on 100 parts by weight of the molded product.

A second heat treatment process is performed on the molded product (block) for crystallization. The second heat treatment process for crystallization is preferably performed at a temperature of about 620 to 780° C. for 10 minutes to 12 hours. At this time, the temperature increase rate to the heat treatment temperature for crystallization is preferably about 0.1 to 20 ° C./min. If the temperature increase rate is too slow, it takes a long time to reduce productivity, and if the temperature increase rate is too fast, the temperature rises rapidly. Since thermal stress may be applied, it is preferable to raise the temperature at a temperature increase rate within the above range. Crystallization is performed inside the block by the heat treatment process, and mechanical strength of the block is increased by the crystallization. After heat treatment for crystallization, it is preferable to slowly cool (slow cool) to room temperature in the same way as natural cooling.

After the crystallization and cooling, the phosphate-calcium-based glass ceramic block may be polished to impart gloss and barrel processing may be performed to remove fine burrs. The barrel processing process may use a barrel grinder or the like.

The phosphate-calcium-based glass ceramic block manufactured according to the manufacturing method of the present invention may be used after being processed with CAD/CAM to be used as a dental restorative material. The calcium phosphate-based glass ceramic block has mechanical strength suitable for machining by CAD/CAM, and thus has excellent cutting processability and ease of handling.

In addition, the phosphate-calcium-based glass ceramic block according to the present invention has excellent processability for dental restorations by the CAD/CAM processing method, can be precisely processed, has density and thermal conductivity similar to that of teeth, and has biocompatibility and aesthetics. It is excellent and has mechanical properties applicable to the CAD/CAM processing method, so it can be processed using the CAD/CAM processing method, so the processing time of dental restorations can be shortened.

Hereinafter, the present invention will be described in more detail through examples and the like according to the present invention, but the scope of the present invention is not limited by the examples presented below.

[Example]

To manufacture a glass ceramic block, Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , CaCO ₃ , Fe ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , CoO, and NiO were weighed and prepared as starting materials.

Considering that H ₃ PO ₄ is changed to P ₂ O ₅ in the subsequent heat treatment process and CaCO ₃ is changed to CaO in the subsequent heat treatment process, each raw material was weighed, and the finally formed phosphate-calcium based glass ceramic block This Al ₂ O ₃ 21.95 mol%, SiO ₂ 34.8 mol%, Na ₂ O 6.47 mol%, MgO 5.37 mol%, P ₂ O ₅ 9.8 mol%, CaO 18.98 mol%, Fe ₂ O ₃ 0.49 mol%, Cr ₂ Each raw material was weighed to include 0.38 mol% of O ₃ , 0.71 mol% of TiO ₂ , 0.84 mol% of CoO, and 0.21 mol% of NiO and prepared as starting materials. Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , CaCO ₃ , Fe ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , CoO, and NiO were added and stirred for 1 hour using a magnetic bar, and continued stirring while slowly dropping H ₃ PO ₄ . The mixture was stirred to form a gel.

The gel-state starting material was dried on a hot plate. The drying was performed at a temperature of about 350° C. for 3 hours until liquid components were removed and only power remained.

The dried product was placed in an alumina (Al ₂ O ₃ ) crucible, and the crucible was charged into a furnace to heat-treat to melt the starting material and quench to form a frit. More specifically, the crucible containing the dried product is charged into a furnace, the temperature of the furnace is raised to a first temperature (400° C.) at a heating rate of 10° C./min using a heating means provided in the furnace, and It was maintained at 1 temperature for 1 hour, the temperature of the furnace was raised to the second temperature (900 ° C) at a heating rate of 10 ° C / min and maintained at the second temperature for 1 hour, and the temperature of the furnace was raised to 10 ° C / min The temperature was raised to a third temperature (1,450 ° C) at a heating rate and maintained at the third temperature for 2 hours to melt the starting material. Frit was obtained by quenching the heat-treated product, and the quenching was performed by pouring into distilled water at room temperature.

The frit obtained by rapid cooling was pulverized, and the pulverization was coarsely pulverized using a jaw crusher and finely pulverized using a pulverizer and a disk mill. , It was sieved with a sieve of 325 mesh (45 μm).

The pulverized frit was placed in an alumina crucible and heated to soften the frit. The heating was performed for 1 hour at a temperature of 1,350 °C. The heating rate up to the heating temperature was about 10°C/min.

The softened product was poured into a graphite mold and molded into a block shape. At this time, the mold was maintained at a temperature of 500° C. for block formation, and the softened product was poured into the mold and maintained at a temperature of 500° C. for 1 hour.

After holding at 500 ° C. for 1 hour, the temperature of the mold was slowly cooled, and then the mold was demolded.

Li ₂ CO ₃ was applied to the surface of the block thus obtained. As the coating method, a method of immersing a block in a Li ₂ CO ₃ solution was used, and the Li ₂ CO ₃ solution was a solution obtained by adding Li ₂ CO ₃ to ethanol. After applying Li ₂ CO ₃ to the surface of the block, a drying process was performed, and the drying process was performed at a temperature of 60° C. for 4 hours.

A heat treatment process was performed on the block for crystallization. The heat treatment process for crystallization was performed at a temperature of 700° C. for 1 hour. At this time, the heating rate up to the heat treatment temperature for crystallization was about 1 ° C./min, and after the heat treatment for crystallization, it was naturally cooled to room temperature.

The physical properties of the glass-ceramic blocks prepared as described above and those of natural teeth are shown in Table 1 below and compared.

[Table 1]

As shown in Table 1, the phosphate-calcium-based glass-ceramic block prepared according to the embodiment of the present invention has similar density and thermal conductivity to natural teeth, and is superior in flexural strength and Vickers hardness to natural teeth, and is similar to conventional teeth. It was confirmed that it was superior to the block containing the material. Accordingly, it was confirmed that it has mechanical properties that can be used for CAD/CAM processing by having improved flexural strength and Vickers hardness, and is similar to natural teeth.

Claims (13)

In the phosphate-calcium-based glass ceramic block capable of CAD / CAM processing,
10 to 50 mol% Al ₂ O ₃ , 20 to 50 mol% SiO ₂ , 3 to 10 mol% Na ₂ O, 3 to 10 mol% MgO, 3 to 10 mol% P ₂ O ₅ , and 5 to 20 mol% CaO contains %,
0.001 to 5 mol% of Fe ₂ O ₃ , 0.001 to 5 mol% of Cr ₂ O ₃ , 0.001 to 5 mol% of TiO ₂ , 0.001 to 5 mol% of CoO and 0.001 to 5 mol% of NiO as auxiliary components;
The phosphate-calcium-based glass ceramic block has physical properties of a density of 3.1 g/cm ³ , a thermal conductivity of 1.1 W/mK, a flexural strength of 340 MPa, and a Vickers hardness of 5.33 GPa, so that the density and thermal conductivity are similar to those of natural teeth, and the flexural strength and a phosphate-calcium-based glass ceramic block, characterized in that its Vickers hardness is superior to that of natural teeth.
delete delete delete delete delete The phosphate-calcium-based glass ceramic block contains 10 to 50 mol% of Al ₂ O ₃ , 20 to 50 mol% of SiO ₂ , 3 to 10 mol% of Na ₂ O, 3 to 10 mol% of MgO, and 3 to 10 mol of P ₂ O ₅ %, and mixing Al ₂ O ₃ , SiO ₂ , Na ₂ O, MgO, H ₃ PO ₄ , CaCO ₃ as raw materials to contain 5 to 20 mol% of CaO;
forming a frit by subjecting the raw material mixture to a first heat treatment so as to be melted and then quenching;
crushing and softening the frit;
Molding the softened product into a block shape and slowly cooling it; and
Forming a glass ceramic block by subjecting the molded product to a second heat treatment for crystallization;
In the step of mixing the raw materials, 0.001 to 5 mol% of Fe ₂ O ₃ , 0.001 to 5 mol% of Cr ₂ O ₃ , 0.001 to 5 mol% of TiO ₂ , 0.001 to 5 mol% of CoO, and 0.001 to 5 mol% of NiO are assisted. Including as a component,
The phosphate-calcium-based glass ceramic block has physical properties of a density of 3.1 g/cm ³ , a thermal conductivity of 1.1 W/mK, a flexural strength of 340 MPa, and a Vickers hardness of 5.33 GPa, so that the density and thermal conductivity are similar to those of natural teeth, and the flexural strength and a method of manufacturing a phosphate-calcium based glass ceramic block, characterized in that its Vickers hardness is superior to that of natural teeth.
delete delete delete delete delete According to claim 7,
The first heat treatment may include raising and maintaining a temperature at a first temperature of 300 to 600° C.;
Raising and maintaining the temperature at a second temperature of 700 to 1100 ° C; and
Raising and maintaining the temperature at a third temperature of 1350 to 1550 ° C. to melt the raw material mixture,
The second heat treatment is a method for producing a phosphate-calcium-based glass ceramic block, characterized in that carried out at a temperature of 620 to 780 ℃.

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