KR20210039553A - Surface treatment method of dental zirconia materials - Google Patents

Abstract

The present invention relates to a surface treatment method for a dental zirconia material using zirconia slurry, which increases the surface roughness of the zirconia material to induce a maximum bonding strength with an object. More specifically, according to the present invention, the method comprises: a forming step (S100) of using zirconia powder containing a binder to mold the zirconia powder into a set shape; a molded article calcination step (S200) of calcining the molded article by heat treatment; a shape processing step (S300) of processing the calcined molded article into a desired shape through a mill; a slurry generation step (S400) of preparing slurry by using the zirconia powder of the same material as that of the molded article; a slurry application step (S500) of performing surface treatment by applying the zirconia slurry to the surface of the molded article; and a molded article sintering step (S600) of sintering the surface-treated molded article to implement surface roughness.

Description

Surface treatment method of dental zirconia materials

The present invention relates to a method for treating a surface of a dental zirconia material, and more particularly, to a method for treating a surface of a dental zirconia material using a zirconia slurry that increases the surface roughness of the zirconia material to maximize the bonding strength with the object. About.

In general, Zirconia has excellent mechanical properties that are not insufficient to be used as a structural ceramic material in general industries, and has excellent biocompatibility and biocompatibility, as well as resistance to corrosion and no toxic reaction to the living body. As it is known, it is widely used in the sale of various bioceramic materials such as bone substitute materials in orthopedic surgery, dental prosthetic materials, and dental implant materials.

In order to enhance the utility of such zirconia as a biological ceramic, many studies on the surface treatment of zirconia materials have been conducted.

For example, among the surface treatment methods for strengthening the bonding strength of zirconia materials, the most basic method is sandblasting, and the principle is that the physical roughness of the surface is increased by spraying ceramic media having a set size on the sintered zirconia surface at high pressure. It's a way to make it happen.

On the other hand, as an example of the surface treatment technology of dental materials using the sand blasting technique, Patent Publication No. 10-2014-0045398 "Dental Sand Blasting Device" is published, and the above technology is a powder supply unit in which powder is stored and a powder It consists of a compressed air supply unit that supplies compressed air to be mixed with the powder discharged from the supply unit, and a control unit that controls the amount of powder and the air pressure of the compressed air.This technology independently controls the amount of powder supplied and the air pressure of the compressed air.

The above-described sandblasting technique is the most intuitive way to improve surface roughness, and has the advantage of being easy to apply, but various variables such as media type, size, and spray pressure control can cause cracking due to external force or There is a problem that the roughness cannot be precisely controlled.

Another example of the surface treatment method for enhancing the bonding strength of the zirconia material is to etch the surface of the zirconia material using an etching solution or a mixed etching solution such as an aqueous nitric acid solution, an aqueous sulfuric acid solution, an aqueous hydrochloric acid solution, and an aqueous hydrofluoric acid solution. The method using the above etching solution is a method of increasing the surface roughness by removing grain by-products or grain aggregates from the target ceramic material.

As an example of techniques related to surface treatment of a dental material using an etching solution, Korean Patent Publication No. 10-2015-0069505 "a surface etchant composition of a dental zirconia ceramic and a method of manufacturing a tooth restoration using the same" is disclosed. The above technology proposes a technology for manufacturing dental restorations such as crowns, inlays, onlays, veneers, laminates, etc. using a mixed etchant consisting of hydrofluoric acid, sulfuric acid, catalyst and ethyl alcohol.

However, since the above technology uses a solution made of an acid, it is difficult to secure the stability of the process, and since it artificially induces bonding to the surface, it is accompanied by a problem that mechanical properties are deteriorated by an external force.

Another example of a surface treatment method for strengthening the bonding strength of a zirconia material is a method of attaching a phosphate-calcium-based heterogeneous material such as HAp (Hydroxy Apatite) and β-TCP to the surface of the zirconia material. Since the above phosphate-calcium-based material has the same chemical structure as human bone, it is excellent as a surface treatment agent that induces rapid fusion with bone by attaching it to the zirconia material using various methods. In particular, phosphate-calcium-based materials have been studied as a method for surface treatment of zirconia-based dental implant fixtures.

As an example of the techniques related to the surface treatment of dental materials using the above phosphate-calcium-based heterogeneous materials, Korean Patent Publication No. 10-2014-0011475 "Coating a calcium phosphate layer using a hydrothermal method on an implant fixture" is disclosed. The above technology includes a fixture blasting step for blasting the fixture surface, a fixture etching step for etching the surface of the blasted fixture using sodium hydroxide solution, a calcium phosphate compound manufacturing step for preparing a calcium phosphate compound, and a fixture etched with sodium hydroxide solution. We present a technology that can minimize the phenomenon of delamination from the surface of the implant fixture by dissolving in a living body consisting of a fixture hydrothermal treatment step in which the calcium phosphate layer is coated by a hydrothermal method using an autoclave and a calcium phosphate compound.

However, the surface treatment technology of a dental material using a phosphate-calcium-based heterogeneous material could not completely solve the peeling problem.

In addition, a method of mixing or attaching different types of ceramics (bioglass, bio-glass) to the surface is used, but there may be a problem of peeling or deterioration of mechanical properties because the chemical bond with the heterogeneous material is not tight.

Republic of Korea Patent Publication No. 10-2014-0045398 "Dental sand blasting device" Republic of Korea Patent Publication No. 10-2015-0069505 "Surface etchant composition of zirconia ceramic for dental use and method for manufacturing tooth restorations using the same" Korean Laid-Open Patent Publication No. 10-2014-0011475 "Coating method of calcium phosphate layer using hydrothermal method on implant fixture"

The present invention was created in order to more actively solve the above problems, by applying a zirconia slurry made of the same material as the molded product to the surface of the molded product, and then sintering it to achieve excellent surface roughness. It is a task to be solved to provide a series of methods for maximizing the bonding strength of an object to a dental prosthesis made of zirconia materials such as crowns, copings, and laminates as the positively improved.

In order to achieve the above problem, the surface treatment method of the dental zirconia material proposed by the present invention is as follows.

The method for surface treatment of a zirconia material proposed by the present invention includes the step of generating a molded product (S100) of forming into a set shape using zirconia powder containing a binder; Calcination step of calcining the molded product by heat treatment (S200); A shape processing step (S300) of processing the calcined molding into a desired shape through a milling machine; Slurry generation step (S400) of preparing a slurry using zirconia powder of the same material as the molded product; Slurry application step (S500) of applying a zirconia slurry to the surface of the molded product for surface treatment; It characterized in that it consists of; a molding sintering step (S600) of implementing the surface roughness by sintering the surface-treated molding.

In addition, the above molding production step (S100) is a material preparation step (S110) of mixing various types of zirconia powders so that the producers can exhibit desired characteristics; and various powders such as compression, injection, and slip casting of the blended zirconia powder. It characterized by consisting of; forming a molded article forming step (S120) of forming a target shape using a molding method; And, a cold hydrostatic pressure process step (S130) solving the density non-uniformity occurring in the process of forming the molded article; characterized in that it consists of.

In addition, the above molding calcination step (S200) is a molding degreasing step (S210) of removing the organic binder mixed in the molding whose internal density is stabilized; And, the molding heat treatment step of ensuring that the molded product has hardness and density conditions for mechanical processing. (S220); characterized in that it consists of.

In addition, the slurry generation step (S400) is characterized in that it consists of mixing zirconia powder, carbon powder, a binder, a dispersant, and a solvent.

In addition, the zirconia slurry is characterized in that it contains 1 to 20 parts by weight of zirconia powder, 1 to 20 parts by weight of carbon powder, 0.1 to 10 parts by weight of a binder, and 0.1 to 10 parts by weight of a dispersant based on 100 parts by weight of the solvent. .

In addition, the slurry generation step (S400) is characterized in that the viscosity adjusting member is further mixed to adjust the viscosity of the slurry.

In addition, the slurry generation step (S400) is mixed using a ball mill equipment equipped with a ball made of zirconia material to increase mixing efficiency, and the ball mill equipment controls the mixing efficiency according to the size of the zirconia ball and the rotation speed of the equipment. It is characterized by that.

In addition, the slurry application step (S500) is characterized in that it is performed by selecting either a spraying method using a sprayer or an application method using a brush.

In addition, the above molding sintering step (S600) is characterized in that it is performed under general sintering conditions of 1,300 to 1,800°C.

According to the present invention having the above-described configuration, due to the method of sintering after applying the zirconia slurry to the surface of the molded object, particles of the slurry adhere to the surface of the molded object, thereby increasing the surface roughness and increasing the surface area, thereby increasing the bonding strength with the object. There is an effect that can be improved more fundamentally.

In addition, the present invention treats the surface using a slurry of the same material as the zirconia molded product, so that the existing peeling problem can be completely solved, and the cleaning process is also excluded because it is not necessary to undergo acid treatment like the existing etching. Such stability can be secured, and the zirconia powder contained in the slurry can be applied without any other physical external force, so that the stability of physical properties can be further secured.

1 is a flow chart sequentially listing a method for treating a surface of a dental zirconia material constructed according to a preferred embodiment of the present invention.
2 and 3 are actual photographs showing a method of applying a zirconia slurry configured according to a preferred embodiment of the present invention.
Figure 4 is a cross-sectional view showing a simplified concept that the zirconia slurry applied to the surface of the molded article is attached to the surface of the molded article while passing through a sintering process.

Hereinafter, with reference to the accompanying drawings, the configuration of the present invention and the actions and effects thereof will be described collectively.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to embodiments described later in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only this embodiment is intended to complete the disclosure of the present invention, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. In addition, the same reference numerals refer to the same elements throughout the entire specification.

The present invention relates to a method for surface treatment of a zirconia material using a zirconia slurry.

Above all, the present invention is a dental zirconia material using a zirconia slurry to increase the bonding strength with the object by increasing the surface roughness of the zirconia material by surface-treating the zirconia slurry of the same material on the surface of the target zirconia material. Note that it relates to the surface treatment method of.

1 is a flow chart sequentially listing a method for surface treatment of a zirconia material using a zirconia slurry constructed according to a preferred embodiment of the present invention.

As shown in FIG. 1, the method for treating the surface of a zirconia material of the present invention includes the step of generating a molded product (S100) of forming a molded product into a set shape using zirconia powder containing a binder; And, a calcining step of heat-treating the molded product and calcining it (S200) ); And, a shape processing step (S300) of processing the calcined molded product into a desired shape through a milling machine; And, A slurry generation step (S400) of manufacturing a slurry using zirconia powder of the same material as the molded product; And, The molded product It consists of a slurry coating step (S500) of applying a zirconia slurry to the surface to treat the surface; and a molding sintering step (S600) of sintering the surface-treated molding to achieve surface roughness.

The molding shape proposed in the above molding creation step (S100) of the present invention is an example for processing using a dental CAD cam equipment in a circular or square shape, and this is only a selection for a more smooth description of the present invention, and is limited thereto. It is not.

The above molding production step (S100) includes a material preparation step (S110) of mixing zirconia powder containing various types of binders so that the producers can exhibit the desired characteristics, and various types of zirconia powder such as compression, injection, and slip casting. It consists of a molded product forming step (S120) of forming a molded product into a target shape using a powder molding method, and a cold hydrostatic pressure process step (S130) of eliminating density unevenness occurring in the process of forming the molded product.

For example, the above molded product basically uses a method of charging zirconia powder into a mold and compression molding according to the shape of the mold, but it can be replaced by injection molding or slip casting depending on the purpose of use.

In the above cold hydrostatic pressure process step (S130), a cold isotropic pressure (CIP) process is performed so as to suppress the non-uniformity of the internal density that may occur during the process of forming the ceramic powder. The above cold hydrostatic pressure is applied to the molded article at a pressure in the range of about 10 to 300 MPa for 1 to 120 minutes, which is a very desirable condition in which the internal density can be balanced.

In addition, the above molding calcination step (S200) includes a molding degreasing step (S210) of removing the organic binder mixed in the molding whose internal density is stabilized, and a molding heat treatment step ( S220).

It is preferable to perform the above molding degreasing step (S210) at a temperature of about 100 to 600° C. for about 10 minutes to 120 hours.

The above molding heat treatment step (S220) is a process of calcining the degreased molding, and after charging it into a furnace such as an electric furnace in order to have hardness and density conditions suitable for machining, about 10 minutes to 60 hours at about 600 to 1,200°C. Perform while. It is preferable to increase the heating rate for the above calcination to 1 to 50°C/min.For example, when the heating rate is slower than the above conditions, the production rate decreases, resulting in a decrease in productivity. Since the product may be deformed due to thermal stress caused by temperature rise, it is desirable to proceed with the above conditions.

The above shape processing step (S300) is a step of processing the stabilized molded product into an artificial tooth shape, and the molded product having stabilized internal density is processed into an artificial tooth shape using a dental processing system. For example, the above dental processing system can be loaded into a milling machine such as a computerized numerical controller (CNC) and processed into a target denture shape or by using a computer-aided design (CAD)/computer-aided manufacturing (CAM) system process. May be.

On the other hand, zirconia (Zr) constituting the above molding is an element having extremely high corrosion resistance to acids and alkalis as a transition metal of the fifth period belonging to the titanium group on the periodic table. Such zirconia has excellent performance such as high strength, thermal stability, and high corrosion resistance, and in the present invention, it is prepared in consideration of the size or blending ratio of the powder in order to have excellent molding conditions.

The above slurry generation step (S400) is a step of preparing a slurry using zirconia powder of the same material as the molded product, and the slurry produced through the step becomes a means capable of expressing roughness on the surface of the molded product.

As mentioned above, the molded product of the present invention uses zirconia powder as a main material, and accordingly, the slurry also uses zirconia powder, which is the same material as the molded product.

It is assumed that the zirconia slurry of the present invention is composed of a mixture of zirconia powder, carbon powder, a binder, a dispersant, and a foaming agent composed of a solvent by a ball mill device.

The most suitable mixing ratio for constituting the above zirconia slurry is composed of 1 to 20 parts by weight of zirconia powder, 1 to 20 parts by weight of carbon powder, 0.1 to 10 parts by weight of a binder, and 0.1 to 10 parts by weight of a dispersant based on 100 parts by weight of the solvent. Configuration.

Meanwhile, the above solvent is premised not to cause a chemical reaction with each of the materials mixed in the zirconia slurry, and in particular, in the present invention, distilled water is used as a preferred embodiment.

The above zirconia slurry induces the operator's selection by presenting various conditions such as the size and amount of zirconia powder, the size and amount of carbon powder, or the amount applied to the surface of the molded product in order to variously control the surface roughness of the molded product.

Example 1 below shows the experimental process of measuring the surface roughness of a molded product according to the concentration of zirconia powder and the result derived accordingly as a table.

The values derived by measuring 1.5 wt%, 3 wt%, and 5 wt% of zirconia powder compared to 100 wt% of the comparative specimen (Control Group) and the solvent are shown in a table.

In addition, the addition amount of other materials other than the above conditions was the same, and each slurry was coated once on the surface of a zirconia circular specimen, and measured using a surface roughness meter.

(Unit: ㎛) division Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Average Control 0.16 0.19 0.17 0.18 0.15 0.17 1.5 wt% 0.54 0.47 0.43 1.08 4.05 1.31 3 wt% 1.71 3.23 1.10 1.04 3.25 2.07 5 wt% 6.01 8.82 3.84 3.13 9.58 6.28

<Comparison table of measured values of surface roughness (Ra) of zirconia specimens>

As can be seen in Table 1, it was confirmed that the zirconia powder increased in proportion to the surface roughness as the concentration increased.

<Surface condition of control specimen>

<Surface condition of the specimen with 1.5wt% zirconia powder concentration>

<Surface condition of the specimen with 3wt% zirconia powder concentration>

<Surface condition of the specimen with 5wt% zirconia powder concentration>

The above picture shows the surface treatment result according to the concentration as a SEM (Scanning Electron Microscope) picture. As shown in the above result, it was confirmed that zirconia slurry was applied to the surface of the molding to form a complex network, thereby increasing the roughness of the surface.

On the other hand, based on the above results, the following experiment was conducted to confirm the effect of strengthening the bonding strength with the actual counterpart.

The bonding strength of the two groups formed by applying a zirconia slurry having a concentration of 3 wt% zirconia powder relative to the control group and 100 wt% solvent and 10 wt% zirconia powder compared to 100 wt% of the solvent was measured. , Below is a simple diagram showing the experimental method of measuring the bonding strength.

<Experimental method of measuring bonding strength for each group>

(Unit: MPa) division Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Average Control 5.9 - 9.32 1.41 12.8 5.89 3 wt% 24.64 27.9 19.92 22.99 17.79 22.65 10 wt% 40.57 38.36 30.18 36.95 32.1 35.63

As shown in Table 2 above, it can be seen that as the surface roughness of the object increases, the bonding strength is also actively improved.

2 and 3 are actual photographs of a process of applying the zirconia slurry prepared according to a preferred embodiment of the present invention to a molded article.

As shown in Figs. 2 and 3, the slurry application step (S500) of the present invention is a step of surface treatment by applying a zirconia slurry to the surface of the molded product. In the present invention, a tool such as a brush is used to apply the zirconia slurry. It is applied to the surface of the molded object or sprayed with a spray to apply it to the surface of the molded object.

4 is a simplified diagram showing a process in which a zirconia slurry is bonded to a molded article by sintering.

As shown in FIG. 4, the sintering step (S600) of the molded product of the present invention is a step of sintering the surface-treated molded product to achieve surface roughness, and removes all organic substances except for the zirconia powder contained in the zirconia slurry by vaporizing or oxidizing it. It plays a role.

The above molding sintering step (S600) is performed at a temperature of about 1,300 to 1,800°C under normal atmospheric sintering conditions without special atmosphere sintering, and it is a preferable condition to remove various organic substances without affecting the molded product.

For example, the zirconia molding in the calcined state shrinks by about 18 to 20% in the sintering process. Based on this shrinkage theory, the zirconia slurry applied to the molded product adheres firmly to the molded product, and carbon powder and other organic additives are vaporized or oxidized to completely remove from the surface of the molded product. It deserves to be made essential.

According to the present invention having the above-described configuration, due to the method of sintering after applying the zirconia slurry, particles of the slurry adhere to the surface of the molded object, thereby increasing the surface roughness and expanding the surface area, thereby more fundamentally improving the bonding strength with the object. There is an effect that can be made.

In addition, since the present invention treats the surface using a slurry of the same material as the zirconia molded product, not only can the existing peeling problem be completely solved, but also the cleaning process is excluded because it does not require acid treatment like conventional etching. The stability of the back can be secured, and the slurry can be applied without any other physical external force, so the effect of further securing the stability of physical properties is exerted.

The present invention described above has been described with reference to an embodiment illustrated in the drawings, but this is only exemplary, and various modifications and other equivalent embodiments are possible from those of ordinary skill in the art. Should be clarified. Accordingly, the true technical protection scope of the present invention should be interpreted by the appended claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

S100. Molded product generation step S110. Material preparation stage
S120. Forming the molding step S130. Cold hydrostatic process step
S200. Calcination of the molding step S210. Degreasing step of molding
S220. Heat treatment step of the molding `S300. Shape processing step
S400. Slurry generation step S500. Slurry application step
S600. Sintering step of molding

Claims (5)

Creating a molded product in a target shape using zirconia powder (S100);
Calcination step of calcining the molded product by heat treatment (S200);
A shape processing step (S300) of processing the calcined molding into a desired shape through a milling machine;
Slurry generation step (S400) of preparing a slurry using zirconia powder of the same material as the molded product;
A slurry application step (S500) of applying a slurry to the surface of the molded product to surface-treat the surface;
Sintering the molded product to realize surface roughness by sintering the surface-treated molding (S600);
Surface treatment method of a dental zirconia material, characterized in that consisting of.
The method of claim 1,
The above molding generation step (S100),
Material preparation step (S110) of mixing the zirconia powder and the binder at a set ratio;
A molding step (S120) of molding the blended zirconia powder into a target shape through any one of compression, injection, and slip casting;
Cold hydrostatic pressure process step (S130) to eliminate the density unevenness occurring in the process of forming the molded product;
Surface treatment method of a dental zirconia material, characterized in that consisting of.
The method of claim 1,
The above molding calcination step (S200),
Degreasing step (S210) of removing the organic binder mixed in the molded product with stabilized internal density;
Molded product heat treatment step (S220) to ensure that the molded product has hardness and density conditions for machining;
Surface treatment method of a dental zirconia material, characterized in that consisting of.
The method of claim 1,
The above slurry generation step (S400) is a method for surface treatment of a dental zirconia material, characterized in that it consists of mixing zirconia powder, carbon powder, a binder, a dispersant, and a solvent.
The method of claim 1,
The above molding sintering step (S600) is a method for treating a surface of a dental zirconia material, characterized in that it is performed under conditions of 1,300 to 1,800°C.

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