Dental Resin Nano Ceramic Block

Abstract

The present invention relates to a method for manufacturing a dental resin nanoceramic block, and more specifically, to an improved method for manufacturing a dental resin nanoceramic block that is harmless to the human body and satisfies flexural strength and wear resistance, thereby enabling the production of the dental resin nanoceramic block in a simpler manner than casting and lamination processes. In particular, because the flexural strength and wear resistance are excellent, tooth movement is minimized when mounted on the tooth, and resistance to fatigue fracture is high, thereby reducing tooth damage and extending the lifespan of the tooth.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a dental resin nanoceramic block, and more specifically, to an improved method for manufacturing a dental resin nanoceramic block that is harmless to the human body and satisfies flexural strength and wear resistance, thereby enabling the production of the dental resin nanoceramic block in a simpler manner than casting and lamination processes. In particular, because the flexural strength and wear resistance are excellent, tooth movement is minimized when mounted on the tooth, and resistance to fatigue fracture is high, thereby reducing tooth damage and extending the lifespan of the tooth. Background Technology

[0002] Resin nanoceramic blocks are specialized materials used in dental CAD / CAM systems and are used to fabricate aesthetic prosthetics such as inlays, onlays, crowns, and laminates, as shown in [Figure 1] below.

[0003] [Figure 1]

[0004]

[0005] As such, for the ideal restoration of damaged teeth, it is desirable to replace them with materials that have a structure and physical properties similar to natural teeth, and among these, most prosthetics have been made using metal materials, particularly gold, which is considered a symbol of wealth.

[0006] However, as interest in aesthetics increases and awareness of the health and environment of metal restorations such as amalgam grows, the demand for metal restorations is decreasing, while the demand for ceramic restorations is increasing [see Figure 2].

[0007] [Figure 2]

[0008]

[0009] However, ceramics have long been used as dental restorative materials because they not only have excellent biocompatibility but also good chemical durability and color stability, and have a color similar to natural teeth. However, they have limitations, such as being brittle and easily broken, having high hardness which causes severe wear on opposing teeth and leads to occlusal imbalance, and having a much higher elastic modulus than enamel, which can cause a stress shielding effect.

[0010] Ceramic-resin blocks, which are fused with polymer materials, are a technology developed to overcome the disadvantages of ceramics and are experiencing rapid market growth alongside changes in demand.

[0011] Nevertheless, localization is necessary as Japanese products account for the majority of the market, and furthermore, the development of materials is currently insufficient for domestic companies focused on implants.

[0012] In particular, even in the case of Japanese products, although the basic framework consists of ceramics including resin, their relatively high hardness leads to reduced processability of prosthetics and prominent cracking and breakage at thin margins, necessitating improvements. Prior art literature

[0013] Korean Registered Patent No. 10-2466073 (2022.11.08.) Dental hybrid resin block composition and method for manufacturing a dental hybrid resin block using the same The problem to be solved

[0014] The present invention was created to address the various problems of the prior art described above. Its main objective is to provide an improved method for manufacturing dental resin nanoceramic blocks that is harmless to the human body and satisfies flexural strength and wear resistance, thereby enabling the production of dental resin nanoceramic blocks using a simpler method than casting or additive manufacturing processes. In particular, because the blocks exhibit excellent flexural strength and wear resistance, they minimize tooth movement when mounted on teeth, reduce tooth damage by having high resistance to fatigue fracture, and extend the lifespan of the teeth. means of solving the problem

[0015] The present invention provides a method for manufacturing a dental resin nanoceramic block, comprising, as a means to achieve the above-mentioned purpose: a first step of preparing ceramic powder; a second step of mixing a binder with the prepared ceramic powder; a third step of creating a molding composition by adding a filler to the ceramic powder mixed with the binder; a fourth step of placing the molding composition into a mold and heating and pressurizing it to form a block after the third step; and a fifth step of sintering the molded block to form a ceramic block; wherein the ceramic powder:binder:filler are mixed in a ratio of 70% by weight:20% by weight:10% by weight.

[0016] At this time, the ceramic powder of the first step is also characterized by being a mixture of 80% by weight of a mixed powder obtained by mixing silica powder and zirconia powder in a weight ratio of 1:1 and then grinding it with a nanomill, and 20% by weight of lithium disilicate nanopowder.

[0017] In addition, the binder of the second step is a mixture of PMMA (Polymethylmethacrylate) and polyvinyl alcohol in a weight ratio of 4:1; and the filler of the third step is collagen powder. Effects of the invention

[0018] According to the present invention, a dental resin nanoceramic block can be manufactured using a simpler method than casting and additive manufacturing processes, while being harmless to the human body and satisfying flexural strength and wear resistance. In particular, because it has excellent flexural strength and wear resistance, when mounted on a tooth, tooth movement is minimized, and resistance to fatigue fracture is high, thereby reducing tooth damage and extending the lifespan of the tooth, resulting in improved effects. Specific details for implementing the invention

[0019] Hereinafter, preferred embodiments according to the present invention will be described in more detail.

[0020] Prior to a specific description of the present invention, the following specific structural or functional descriptions are illustrative of embodiments according to the concept of the present invention and may be subject to various modifications and may take various forms.

[0021] Therefore, it should be understood that the embodiments according to the concept of the present invention are not intended to be limited to a specific disclosed form, but include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0022] A method for manufacturing a dental resin nanoceramic block according to the present invention includes the process of preparing a ceramic powder binder for making a block and molding the same.

[0023] In other words, since the present invention is manufactured using a powder metallurgy method rather than the conventional casting method, manufacturing costs can be significantly reduced.

[0024] More specifically, a method for manufacturing a dental resin nanoceramic block according to the present invention comprises: a first step of preparing ceramic powder; a second step of mixing a binder with the prepared ceramic powder; a third step of creating a molding composition by adding a filler to the ceramic powder mixed with the binder; a fourth step of placing the molding composition into a mold and heating and pressurizing it to form a block after the third step; and a fifth step of pre-sintering the molded block to create a ceramic block.

[0025] At this time, the ceramic powder prepared in the first step is a biocompatible ceramic powder with improved mechanical properties, and is a step of making ceramic powder by mixing 80% by weight of a mixed powder obtained by mixing silica powder and zirconia powder in a weight ratio of 1:1 and then grinding it with a nanomill, and 20% by weight of lithium disilicate nanopowder.

[0026] In this way, an RNC (Resin nano ceramic) block can be produced by mixing and molding silica powder and zirconia powder with the resin described later.

[0027] A representative RNC block is LAVA Ultimate developed by 3M, but the present invention has the feature of further improving the brittleness, which is a limitation of commercial products, so that it does not break easily and further improves strength, durability, and corrosion resistance.

[0028] However, it can only be classified as an RNC (Resin nano ceramic) block in that it is formed by synthesizing resin in a state where ceramic powders such as silica and zirconia powders have been nano-ground.

[0029] Here, silica and zirconia are representative ceramics and are materials primarily used in the field of dental restoration materials.

[0030] In addition, lithium disilicate is applied as a material for dental restorations to which the present invention belongs, and by providing a biaxial flexibility strength in the range of 360 MPa to 400 MPa, it has the characteristic of overcoming and supplementing the limit of the flexibility strength of metal ceramics, which is 80 to 100 MPa, thereby suppressing brittleness.

[0031] This is because lithium disilicate has a unique microstructure composed of small, interlocked, plate-like needle-shaped crystals that are randomly oriented, and this structure prevents cracks from being deflected, blunted, or branched, thereby preventing the cracks from growing larger.

[0032] In addition, the second step described above is a step of adding and mixing a resin that functions as a binder and a filler to the ceramic powder composition, which is a formulation for making RNC.

[0033] The binder used in this step is a mixture of PMMA (Polymethylmethacrylate) and polyvinyl alcohol in a weight ratio of 4:1.

[0034] In this case, the above PMMA is a transparent, colorless, amorphous thermoplastic plastic with excellent stiffness, but since brittleness may increase, polyvinyl alcohol balances this.

[0035] In this case, polyvinyl alcohol, as a water-soluble polymer, secures bonding strength and buffering capacity during sintering treatment, and maintains shock absorption against external forces to ensure molding stability.

[0036] And, the third step is a step of adding a filler to the ceramic powder composition to which a binder has been added, thereby imparting ductility to the ceramic powder composition to which PMMA has also been added, so that brittleness does not occur.

[0037] The filler used in this step is an organic matrix, which can be exemplified by collagen.

[0038] At this time, it is preferable that collagen be added in powder form.

[0039] In addition, the ratio of the final molding composition mixed in the fourth step above is 70% by weight of the ceramic powder composition, 20% by weight of the binder, and 10% by weight of the remaining filler.

[0040] Furthermore, the above fifth step is generally carried out in a known manner, and the present invention falls within this category.

[0041] However, a ceramic block with greater density and durability can be produced by including: a first process of raising the temperature at a rate of 5°C per minute in a sintering furnace maintained in an argon gas atmosphere from room temperature to 600°C and holding it for 2 hours; a second process of raising the temperature at a rate of 5°C per minute after the first process and holding it at 1200-1250°C for 1 hour; and a third process of slowly cooling to room temperature after the second process.

[0042] At this time, the first process above is a process of removing the binder contained in the powder alloy.

[0043] In addition, the second process mentioned above is a process of degreasing to form a pre-sintered ceramic block.

[0044] And, the third process above is an annealing treatment intended to minimize lattice defects in the structure, induce recrystallization, and homogenize the structure by preventing residual stress from occurring.

[0045] Here, "pre-sintering" refers to sintering only up to the degreasing state before full sintering.

[0046] On the other hand, in the present invention, based on 100 parts by weight of the ceramic powder, 1.5 parts by weight of niobium (Nb), 1.5 parts by weight of nickel (Ni), 5 parts by weight of HAP (Hydroxyapatite), and 5 parts by weight of CNC (Cellulose Nanocrystal) may be further added to the ceramic powder.

[0047] At this time, niobium has excellent biocompatibility and is not harmful to the human body, and above all, it has the advantage of suppressing high-temperature oxidation by increasing resistance to oil corrosion and creep characteristics, and especially by improving mechanical properties by forming intermetallic compounds such as Ni3Nb through reaction with nickel.

[0048] Furthermore, nickel not only has excellent corrosion resistance and discoloration resistance, but also contributes to increasing the tensile and flexural strength of the molded block.

[0049] In addition, HAP (Hydroxyapatite) is a bioceramic that possesses properties similar to actual human bone, particularly teeth, making it a biocompatible material with virtually no side effects for denture manufacturing.

[0050] In addition, cellulose nanocrystals, or CNCs, are added to induce linear changes in stiffness and ductility that cannot be achieved with bioceramics alone. This is done to compensate for the disadvantage of being brittle and easily breaking when bioceramics are used alone, as the non-linear nature of these properties can lead to breakage.

[0051] In addition, in order to increase the mixing and dispersion of the binder and the ceramic powder, 10 parts by weight of isopropyl alcohol and 5 parts by weight of barium carbonate may be further added to 100 parts by weight of the binder.

[0052] In this case, isopropyl alcohol increases dispersibility to ensure the components mix well, and barium carbonate promotes aggregation between powders to enhance bonding strength and improve curability.

[0053] Meanwhile, a stain-resistant coating layer composed of a stain-preventing coating composition may be applied to the mold to improve stain resistance.

[0054] The composition for the anti-fouling coating layer above contains dioctyl sulfosuccinate and amidoquat in a molar ratio of 1:0.01 to 1:2, and the total content of dioctyl sulfosuccinate and amidoquat is 1 to 12 weight% with respect to the total aqueous solution.

[0055] The above dioctyl sulfosuccinate and amidoquat are preferably in a molar ratio of 1:0.01 to 1:2. If the molar ratio falls outside this range, there is a problem where the coating properties of the mold are reduced or moisture adsorption on the surface increases after coating, causing the coating film to be removed.

[0056] The above dioctyl sulfosuccinate and amidoquat are preferably present in an amount of 1 to 12 weight percent of the total aqueous composition solution; if the amount is less than 1 weight percent, there is a problem of reduced coating performance of the mold, and if the amount exceeds 12 weight percent, crystal precipitation is likely to occur due to an increase in the thickness of the coating film.

[0057] Meanwhile, it is preferable to apply the present anti-fouling coating composition to a mold by a spray method. In addition, the final coating film thickness of the mold is preferably 900 to 2300 Å. If the thickness of the coating film is less than 900 Å, there is a problem of deterioration in the case of high-temperature heat treatment, and if it exceeds 2300 Å, there is a disadvantage that crystal precipitation is likely to occur on the coating surface.

[0058] In addition, the present stain-resistant coating composition can be prepared by adding 0.1 mol of dioctyl sulfosuccinate and 0.05 mol of amidoquat to 1000 ml of distilled water and then stirring.

[0059] The reason the ratio of the above components and the thickness of the coating film were numerically limited as described above is that, based on the analysis of test results after repeated failures by the inventor, the optimal anti-fouling coating effect was observed at the above ratios.

Claims

Claim 1 A method for manufacturing a dental resin nano-ceramic block comprising: a first step of preparing ceramic powder; a second step of mixing a binder with the prepared ceramic powder; a third step of creating a molding composition by adding a filler to the ceramic powder mixed with the binder; a fourth step of placing the molding composition into a mold and heating and pressurizing it to form a block after the third step; and a fifth step of pre-sintering the molded block to create a ceramic block; wherein the ceramic powder:binder:filler are mixed in a ratio of 70 wt%:20 wt%:10 wt%; the binder in the second step is a mixture of PMMA (Polymethylmethacrylate) and polyvinyl alcohol in a weight ratio of 4:1; and the filler in the third step is collagen powder. Claim 2 A method for manufacturing a dental resin nanoceramic block according to claim 1, wherein the ceramic powder of the first step is characterized by mixing 80% by weight of a mixed powder obtained by mixing silica powder and zirconia powder in a weight ratio of 1:1 and then grinding it with a nanomill, and 20% by weight of lithium disilicate nanopowder. Claim 3 delete

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