Dental prostheses and methods for manufacturing the same

Abstract

The present invention relates to a dental prosthesis having a structure similar to that of natural teeth, and a method for manufacturing the same. The dental prosthesis comprises: a first hardened material layer, which is a hardened material containing ceramic particles dispersed in a polymer matrix, and the ceramic particles have a ceramic particle content of 70 to 90% and an average particle size of 100 to 1,000 nm; and a second hardened material layer, which is adjacent to the inside of the first hardened material layer and has a ceramic particle content of 40 to 60 wt % and an average particle size of 10 to 500 μm. As a result, the dental prosthesis can exhibit a structure similar to that of natural teeth, i.e., a structure and physical properties similar to those of natural teeth, which have an enamel surface and dentin interior. The present invention also discloses a method for manufacturing the dental prosthesis using a 3D printing method.

Description

Technical Field

[0001] The present invention relates to a dental prosthesis made of a cured product containing ceramic particles dispersed in a polymer matrix and a method for manufacturing the same, and more specifically, to a dental prosthesis having a structure similar to that of natural teeth and a method for manufacturing the same using three-dimensional printing technology.

Background Art

[0002] The dental industry is considered to have grown together with the development of equipment and materials used in dentistry. For example, the dental industry has been developed by equipment such as heat-pressing and CAD / CAM (Computer Aided Design / Computer Aided Manufacturing), and the development of materials such as glass ceramics and zirconia, which are suitable materials therefor, has been carried out.

[0003] Due to such changes, in dentistry, improvements such as an improvement in the aesthetic part required by patients and a reduction in the time required for dental treatment by one-day prosthetics have been made. However, due to the difference in physical properties from natural teeth, problems such as wear of adjacent teeth or opposing teeth, or breakage during the food chewing process may appear, and additional problems such as secondary infections in the oral cavity may appear.

[0004] Many studies are being conducted in the field of prosthetics to address this issue, focusing on the structure and physical properties of prosthetics to be similar to those of natural teeth. Natural teeth have a crown composed of enamel and dentin, and their physical properties and structures differ from each other. Enamel has a dense structure with an inorganic content of 85 vol% or more (see Figure 1), while dentin has a porous structure with a nearly similar ratio of inorganic and organic matter (see Figure 2). Due to these differences in materials and structures, the physical properties of enamel and dentin also differ. For example, in terms of elastic modulus, enamel shows a value of approximately 50-110 GPa, while dentin shows a value of approximately 20 GPa or less. In terms of hardness, enamel is reported to show a value of approximately 3-6 GPa, while dentin shows a value of approximately 0.5-1.5 GPa.

[0005] The development of materials with physical properties and structures most similar to natural teeth has been the subject of much research, and various materials have been developed.

[0006] As an example, Korean Patent No. 10-2037401 discloses an artificial tooth material exhibiting light transmittance at the level of natural tooth enamel. This patent describes a silicate glass composition containing 3-5% by weight of ZrO2 to improve wettability for bonding with zirconia, 69-79% by weight of SiO2, 10-13% by weight of Li2O, 3-7% by weight of P2O5, 1-4% by weight of Al2O3, 1.0-2.5% by weight of K2O, 0.1-3% by weight of MO (M = any of Ca, Zn, and Mg), and 0.5-2.0% by weight of a coloring agent, which is heat-treated at 300°C to 600°C for 1 minute to 2 hours, resulting in an SiO2-based silicate glass with a visible light transmittance of 40-70%. The paper describes how applying a silicate glass based on SiO2 to a zirconia outer layer through hot pressure allows for minimal cutting of the zirconia prosthesis, creating a thin, hot bond to its surface while maintaining mechanical and structural stability. Furthermore, the zirconia's color permeates through the thin coating layer, resulting in a highly dynamic and deep color, and thus exhibiting optical properties closer to those of natural teeth.

[0007] On the other hand, Korean Patent No. 10-1840142 discloses a method for manufacturing artificial teeth using a dental photocurable resin composition. This method uses a dental photocurable resin composition containing a radical polymerizable organic compound, a filler, and a photosensitive radical polymerization initiator to produce artificial teeth that possess the required properties such as strength, wear resistance, hardness, and low absorption, as well as excellent aesthetics and functionality. The method can be manufactured smoothly and easily in a short time, especially less than one hour, and specifically describes a manufacturing method based on 3D CAD data.

[0008] However, the technology for prosthetics that structurally have a double structure of enamel and dentin is still insufficient. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Korean Patent No. 10-2037401 [Patent Document 2] Korean Patent No. 10-1840142 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a dental prosthesis that can exhibit a structure and physical properties similar to those of natural teeth, which have a dual structure of enamel and dentin.

[0011] Furthermore, the present invention aims to provide a method for manufacturing dental prostheses that have a double structure by embodying a dense enamel structure and a porous dentin structure similar to natural teeth using three-dimensional printing, and that can exhibit the same structure and physical properties as natural teeth by embodying the physical properties of each. [Means for solving the problem]

[0012] The present invention provides a dental prosthesis having a structure similar to that of natural teeth, comprising a first cured layer containing ceramic particles dispersed in a polymer matrix, wherein the ceramic particle content is 70-90% and the average particle size of the ceramic particles is 100-1,000 nm, and a second cured layer adjacent to the inside of the first cured layer, containing 40-60% by weight of ceramic particles and the average particle size of the ceramic particles is 10-500 μm.

[0013] In a preferred embodiment of the present invention, the first cured layer may satisfy a biaxial flexural strength of 300 to 500 MPa, an elastic modulus of 50 to 110 GPa, and a hardness of 3 to 6 GPa.

[0014] In a preferred embodiment of the present invention, the second cured layer may satisfy a biaxial flexural strength of 100 to 300 MPa, an elastic modulus of 5 to 20 GPa, and a hardness of 0.5 to 1.5 GPa.

[0015] In one embodiment of the present invention, the ceramic particles may be at least one selected from barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glassy material.

[0016] In one embodiment of the present invention, the ceramic particles may have a silane-treated surface.

[0017] In one embodiment of the present invention, the polymer matrix is ​​hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), urethane dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidylmethacrylate (NTGE), polyethylene glycol dimethacrylate (PEG-DMA), and oligocarbonate dimethacrylic acid ester. It may be a cured product of at least one polymerizable organic compound selected from among esters.

[0018] In a preferred embodiment of the present invention, the first cured layer may have a dense structure, and the second cured layer may have a porous structure.

[0019] In one embodiment of the present invention, the cured product may be a product cured by photocuring or thermal curing.

[0020] In one preferred embodiment of the present invention, the prosthesis may be manufactured by three-dimensional printing.

[0021] In another embodiment of the present invention, a method for manufacturing a dental prosthesis by three-dimensional printing using a curable composition containing ceramic particles and a polymerizable organic compound is provided, comprising the steps of: stacking according to a predetermined shape; and curing, using a first curable composition having a ceramic particle content of 70-90% and an average particle size of 100-1,000 nm, and a second curable composition having a ceramic particle content of 40-60% by weight and an average particle size of 10-500 μm as the curable composition, and curing.

[0022] In a manufacturing method according to one embodiment of the present invention, at least one of the following can be used as the ceramic particles: barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glass.

[0023] In the manufacturing method according to an embodiment of the present invention, the polymerizable organic compound can be at least one selected from hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxy propoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), urethane dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidyl methacrylate (NTGE), polyethylene glycol dimethacrylate (PEG-DMA), and oligocarbonate dimethacrylic esters.

[0024] In the manufacturing method according to a preferred embodiment of the present invention, the predetermined shape can be a dense structure imitating the enamel of a natural tooth in the case of the first curable composition, and a porous structure imitating the dentin of a natural tooth in the case of the second curable composition.

[0025] In the manufacturing method according to an embodiment of the present invention, the curing step can be performed by photocuring or thermocuring.

Effects of the Invention

[0026] This invention proposes a dental prosthesis that contains ceramic particles dispersed in a polymer matrix, thereby having a structure and physical properties similar to the enamel and dentin of natural teeth, and a method for manufacturing it using a three-dimensional printing technique. This makes it possible to manufacture dental prostheses that have the high aesthetic quality required for dental prosthesis materials and physical properties similar to adjacent or opposing teeth. Because the dental prosthesis has a structure and physical properties similar to natural teeth, it is expected to prevent problems such as wear on adjacent or opposing natural teeth when implanted in the patient's oral cavity, and secondary infections that may arise as a result. [Brief explanation of the drawing]

[0027] [Figure 1] These are SEM images showing the microstructure of the enamel (Figure 1) and dentin (Figure 2) of a natural tooth. [Figure 2] These are SEM images showing the microstructure of the enamel (Figure 1) and dentin (Figure 2) of a natural tooth. [Modes for carrying out the invention]

[0028] The aforementioned and additional aspects of the present invention will become even clearer from preferred embodiments described with reference to the accompanying drawings. The following descriptions will be detailed so that those skilled in the art can easily understand and reproduce them.

[0029] Figures 1 and 2 are SEM images showing the microstructure of the enamel (Figure 1) and dentin (Figure 2) of a natural tooth.

[0030] The present invention is part of an effort to maximize the realization of natural teeth having such a double structure using a cured material containing ceramic particles dispersed in a polymer matrix, and proposes a dental prosthesis comprising: a first cured layer having a ceramic particle content of 70-90% and an average particle size of 100-1000 nm; and a second cured layer adjacent to the inside of the first cured layer, having a ceramic particle content of 40-60% by weight and an average particle size of 10-500 μm.

[0031] In this invention, we have determined that the microstructural and physical differences between enamel and dentin in natural teeth are influenced by the content and structure of inorganic and organic materials. We have considered a curable composition containing polymerizable organic compounds and ceramic particles as a material that can structurally express these differences, and we have confirmed that using such a curable composition and a three-dimensional printing technique (3D printing) is optimal for realizing the microstructure. In particular, we have confirmed that when using two types of curable compositions with controlled ceramic particle size and content to realize a double structure, it is possible to obtain a cured product that is physically close to the enamel and dentin of natural teeth.

[0032] From this perspective, a preferred dental prosthesis comprises a first hardened layer having a ceramic particle content of 70-90% and an average particle size of 100-1,000 nm, and a second hardened layer having an average particle size of 10-500 μm. In this case, the second hardened layer is formed adjacent to the inside of the first hardened layer, but this can be embodied by reflecting the layered structure of enamel and dentin of natural teeth, and is not limited to the shape of the layer.

[0033] In the dental prosthesis of the present invention, the higher the ceramic particle content and the smaller the size of the ceramic particles, the greater the density of the ceramic particles after hardening, resulting in improved physical properties.

[0034] Specifically, it can be observed that the smaller the size of the ceramic particles and the higher the ceramic particle content, the more the properties exhibited in the mixture are similar to those of ceramics, and high physical properties can be expected. On the other hand, it can be confirmed that the higher the polymer content, the lower the physical properties of the mixture. Furthermore, even if the ceramic content in the polymer is similar, the smaller the size of the ceramic particles, the greater the distribution of ceramics, which can indicate an improvement in physical properties.

[0035] From this perspective, it is preferable that the content of ceramic particles in the first cured layer is 70% to 90% by weight of the total composition of the first cured layer, and that the average particle size of the ceramic particles in the first cured layer is 100 nm to 1,000 nm.

[0036] On the other hand, the content of ceramic particles in the second cured layer is preferably 40% to 60% by weight of the total composition of the second cured layer, and the average particle size of the ceramic particles in the second cured layer is preferably 10 μm to 500 μm.

[0037] When two hardened layers are included in the polymer matrix, with controlled content and size of ceramic particles dispersed within, the first hardened layer can exhibit physical properties that satisfy a biaxial flexural strength of 300-500 MPa, an elastic modulus of 50-110 GPa, and a hardness of 3-6 GPa, while the second hardened layer can exhibit physical properties that satisfy a biaxial flexural strength of 100-300 MPa, an elastic modulus of 5-20 GPa, and a hardness of 0.5-1.5 GPa. These are equivalent physical properties to those of natural tooth enamel and dentin, respectively, and can embody enamel that is structurally dense and exhibits high physical properties to play a role in chewing food and as a contact surface with adjacent and opposing teeth, and dentin that has appropriate elasticity and flexibility to alleviate stress that occurs during the chewing process.

[0038] In the above and below, "ceramic particles" can refer to, and are not limited to, a variety of inorganic materials that can be used in the manufacture of dental prostheses. However, as a specific example, at least one selected from barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glassy materials can be mentioned.

[0039] On the other hand, it goes without saying that treating the surface of such ceramic particles with silane is preferable because it improves the bonding strength with the polymer matrix, ultimately improving the mechanical properties of the dental prosthesis. Examples of usable silane coupling agents include silane coupling agents having reactive functional groups such as (meth)acrylic groups, epoxy groups, vinyl groups, amino groups, and mercapto groups, and one or more of these can be used, but are not limited to these.

[0040] The polymer constituting the matrix in the dental prosthesis of the present invention may include, but is not limited to, cured products of thermopolymerizable or photopolymerizable organic compounds known in the art, but examples include hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), urethane dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidylmethacrylate (NTGE), and polyethylene glycol dimethacrylate. Examples include cured products of at least one polymerizable organic compound selected from dimethacrylate, PEG-DMA, and oligocarbonate dimethacrylic esters.

[0041] In this invention, when manufacturing dental prostheses using a cured product containing ceramic particles dispersed within such a polymer matrix, it is possible to manufacture prostheses having a double structure consisting of enamel and dentin similar to natural teeth using three-dimensional printing.

[0042] Currently, in the manufacture of dental prostheses, 3D printing methods using metals or polymers are widely employed. 3D printing using metals involves melting the metal with a laser and layering the molten liquid, while 3D printing using polymers involves layering polymers using a photocuring agent and curing the polymers with a light source.

[0043] In 3D printing, printing using only ceramics is still under research, and most methods involve mixing and curing with organic compounds. In this process, important variables include the ratio of ceramic to polymer content and the particle size of the ceramic, which allow for adjustment of the physical properties after curing. In this invention, the ratio of ceramic particles and particle size are controlled as described above, and the structure of natural teeth is reproduced using 3D printing.

[0044] Natural teeth, in the case of enamel, have a dense structure as shown in Figure 1, and in the case of dentin, have a porous structure, more specifically a tubular pore structure with a size of approximately 100 to 1000 nm, as shown in Figure 2. In this invention, in order to similarly embody such natural teeth, three-dimensional printing is used to enable the realization of such microstructures.

[0045] According to the present invention, a double structure similar to that of natural teeth can be realized using three-dimensional printing, and changes in physical properties that appear after hardening can be provided depending on the materials that make up each structure, the content of each material, and the particle size of the materials. The dental prosthesis of the present invention exhibits a color and physical properties very similar to that of teeth, making it suitable for use as a dental prosthetic material.

[0046] One of the ultimate goals of dental prostheses is to exhibit aesthetic and physical properties that most closely resemble natural teeth, and to ensure that they blend most naturally with surrounding teeth when implanted in the oral cavity.

[0047] To this end, the present invention proposes a method for manufacturing dental prostheses that exhibit a double structure similar to natural teeth using a three-dimensional printing method, and that can embody the enamel and dentin of natural teeth by adjusting the physical properties by controlling the content of ceramics and polymers and the size of ceramic particles.

[0048] Specifically, the method for manufacturing a dental prosthesis having a structure similar to that of natural teeth according to the present invention is a method for manufacturing a dental prosthesis by three-dimensional printing using a curable composition containing ceramic particles and a polymerizable organic compound, comprising the steps of: laminating according to a predetermined shape using a first curable composition having a ceramic particle content of 70-90% and an average particle size of 100-1,000 nm, and a second curable composition having a ceramic particle content of 40-60% by weight and an average particle size of 10-500 μm, and curing.

[0049] To manufacture dental prostheses using ceramics with a structure similar to natural teeth, three-dimensional printing methods such as SLA (Stereo Lithography Apparatus) and DLP (Digital Lighting Process) are suitable. These methods involve printing each layer to have the structure of enamel and dentin of natural teeth, and then polymerizing them by curing polymerizable organic compounds using a light source or heat source. An example of a light source in this case is a 300-600 nm range, but it is not limited to this range.

[0050] In order to have physical properties similar to those of natural tooth enamel and dentin, various physical properties can be ensured by controlling the change in ceramic particle size and the content of ceramics and polymers. From this perspective, a first curable composition having a ceramic particle content of 70-90% and an average particle size of 100-1,000 nm, and a second curable composition having a ceramic particle content of 40-60% by weight and an average particle size of 10-500 μm are used to print and laminate each layer.

[0051] In this case, the ceramic particles used can be at least one selected from barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glass, as described above, and it goes without saying that such ceramic particles may have a silane-treated surface.

[0052] Furthermore, at least one polymerizable organic compound can be selected from hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), urethane dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidylmethacrylate (NTGE), polyethylene glycol dimethacrylate (PEG-DMA), and oligocarbonate dimethacrylic esters.

[0053] In a solution of such polymerizable organic compound, ceramic particles treated with silane, for example, are mixed according to the ceramic particle size and ceramic particle content ratio of the two curable compositions described above, and these curable compositions are then placed into the 3D printing equipment.

[0054] These curable compositions are used to laminate the material into predetermined shapes. In the case of the first curable composition, the predetermined shape is a dense structure that mimics the enamel of a natural tooth with a composition that makes up the exterior of the tooth, and in the case of the second curable composition, it is a porous structure that mimics the dentin of a natural tooth with a composition that makes up the interior, specifically a tubular porous structure. The material is laminated in this manner while hardening is carried out.

[0055] In this case, curing can be photocuring or thermal curing, but in the case of photocuring, the material is irradiated with a light source so that photocuring occurs.

[0056] When using a photocuring agent, curing can be achieved by supplying the necessary light source, and in the case of a thermocuring agent, curing can be achieved by supplying the necessary temperature.

[0057] According to the present invention, a prosthesis can be obtained by using a three-dimensional printing method with a first curable composition and a second curable composition, comprising a first cured layer having a microstructure that mimics enamel as shown in Figure 1 and a second cured layer having a microstructure that mimics dentin as shown in Figure 2. Such a prosthesis can produce a cured layer that exhibits the physical properties shown in Table 1 below. These are physical properties that correspond to the enamel and dentin of natural teeth, and according to the present invention, it is possible to provide a dental prosthesis having a structure similar to that of natural teeth.

[0058] [Table 1]

[0059] Although the present invention has been described with reference to one illustrated embodiment, this is merely illustrative, and those with ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. [Industrial applicability]

[0060] The present invention relates to a dental prosthesis comprising a cured product containing ceramic particles dispersed in a polymer matrix, and a method for manufacturing the same. More specifically, it relates to a dental prosthesis having a structure similar to that of a natural tooth, and a method for manufacturing the same using three-dimensional printing technology.

[60] The present invention proposes a dental prosthesis that has the same structure and physical properties as the enamel and dentin of natural teeth by containing ceramic particles dispersed in a polymer matrix, and a method for manufacturing the same using a three-dimensional printing technique. This makes it possible to manufacture dental prostheses that have the high aesthetics required for dental prosthesis materials and physical properties similar to adjacent or opposing teeth. Because the dental prosthesis has the same structure and physical properties as natural teeth, it is expected that problems such as wear of adjacent or opposing natural teeth when implanted in the patient's oral cavity, and secondary infections that may arise as a result can be prevented in advance.

Claims

1. A cured product comprising a first cured layer containing ceramic particles dispersed within a polymer matrix, wherein the ceramic particle content is 70-90% and the average particle size of the ceramic particles is 100-1,000 nm, The present invention comprises a second cured layer adjacent to the inside of the first cured layer, having a ceramic particle content of 40 to 60% by weight and an average particle size of 10 to 500 μm, The first hardened layer is modeled after enamel, and the second hardened layer is modeled after dentin, and the dental prosthesis has a porous structure with pores of size 100 to 1,000 nm.

2. The dental prosthesis according to claim 1, characterized in that the first cured layer satisfies a biaxial bending strength of 300 to 500 MPa, an elastic modulus of 50 to 110 GPa, and a hardness of 3 to 6 GPa.

3. The dental prosthesis according to claim 1, characterized in that the second hardened layer satisfies a biaxial bending strength of 100 to 300 MPa, an elastic modulus of 5 to 20 GPa, and a hardness of 0.5 to 1.5 GPa.

4. The dental prosthesis according to claim 1, characterized in that the ceramic particles are at least one selected from barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glass.

5. The dental prosthesis according to claim 1 or 4, characterized in that the ceramic particles have a silane-treated surface.

6. The polymer matrix consists of hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), and urethane dimethacrylate. The dental prosthesis according to claim 1, characterized in that it is a cured product of at least one polymerizable organic compound selected from among dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidyl methacrylate (NTGE), polyethylene glycol dimethacrylate (PEG-DMA), and oligocarbonate dimethacrylate esters.

7. A method for manufacturing dental prostheses by three-dimensional printing using a curable composition containing ceramic particles and polymerizable organic compounds, The process involves laminating a first curable composition, which contains 70-90% ceramic particles and has an average particle size of 100-1,000 nm, and a second curable composition, which contains 40-60% by weight of ceramic particles and has an average particle size of 10-500 μm, according to a predetermined shape. A method for manufacturing a dental prosthesis, including a hardening step.

8. The method for manufacturing a dental prosthesis according to claim 7, characterized in that at least one of the following is used as the ceramic particle: barium silicate crystallized glass, leucite crystallized glass, alumina, zirconia, and glass.

9. Polymerizable organic compounds include hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), and urethane dimethacrylate. A method for producing a dental prosthesis according to claim 7, characterized by using at least one selected from among dimethacrylate (UDM), biphenyl dimethacrylate (BPDM), n-tolylglycine-glycidyl methacrylate (NTGE), polyethylene glycol dimethacrylate (PEG-DMA), and oligocarbonate dimethacrylate esters.

10. The method for manufacturing a dental prosthesis according to claim 7, characterized in that the predetermined shape is a dense structure that mimics the enamel of a natural tooth in the case of the first curable composition, and a porous structure that mimics the dentin of a natural tooth in the case of the second curable composition.

11. The method for manufacturing a dental prosthesis according to claim 7, characterized in that the curing step is carried out by photocuring or thermal curing.

Images