KR101911280B1 - Co-Cr-Nb BASED DENTAL CASTING ALLOY - Google Patents

Abstract

The present invention relates to a new Co-Cr-Nb based alloy, and more specifically relates to a Co-Cr-Nb based alloy, in which an alloy element such as Nb or the like is added to a Co-Cr based alloy such that the Co-Cr-Nb based alloy has less elution of harmful elements with an excellent castability compared to a conventional dental casting alloy, and especially has excellent castability when applied to a partial denture. Thus, the Co-Cr-Nb based alloy can be easily casted and formed via an excellent casting flow, and is able to reduce destruction of a false teeth frame and a wire clasp. The Co-Cr-Nb based alloy according to the present invention comprises: 60-61 wt% of Co; 28-30 wt% of Cr; 4-5 wt% of Nb; 2-4 wt% of W; 0.5-1.5 wt% of Si; 0.3-1 wt% of Mo; 0.5-1.5 wt% of Mn; 0.05-0.5 wt% of Ti; and 0.1-0.5 wt% of C.

Description

Co-Cr-Nb based dental cast alloy {Co-Cr-Nb BASED DENTAL CASTING ALLOY}

The present invention relates to a novel Co-Cr-Nb-based alloy, and more particularly to a Co-Cr-Nb-based alloy which is obtained by dissolving a harmful component Cr-Nb alloy which can be easily molded through casting and can reduce the breakage of clasp when it is applied to partial denture. .

The metal materials used in the medical field must satisfy two conditions. First, all of the metals (iron, chromium, cobalt, nickel, titanium, molybdenum, etc.) should be bio- In the case of a very small amount of the substance does not cause a rejection reaction, but if it exists at a certain level or more, it may cause a rejection reaction in vivo, so that the alloying element should be added at a level not causing the in vivo rejection reaction. (Mechanical strength, abrasion resistance, elasticity, brittleness, durability, and the like) in performing the function, while preventing the deterioration of the mechanical properties in the body during use.

In recent years, stainless steel, a Ni-Cr alloy, a Co-Cr alloy, and a Ti alloy have been used as dental materials since a long time ago, and gold (Au) Etc., have been developed and used. Representative non-precious metal prosthetic alloys include Co-Cr alloys and Ni-Cr alloys.

The Co-Cr alloy was first introduced by Elwood Haynes, USA in 1907, and was named "Haynes Stellites" or "Stellite alloy." It has been used industrially as a cutting tool and a wear resistant alloy for heat treatment. Alloys. Co-Cr alloys for machining are excellent in mechanical strength, but contain a large amount of Ni harmful to the human body. Co-Cr alloys for casting are mainly used for dental materials.

The first Co-Cr alloy used for dental casting is Vitallium alloy (65Co-30Cr-5Mo), which has a specific gravity of about 1/2 and a modulus of elasticity about twice that of gold alloy. Therefore, it is possible to thin the thickness of the denture, to increase the wear resistance and corrosion resistance by adding the Cr component, and the biocompatibility is better than the gold alloy and is widely used as a dental material.

On the other hand, the Ni-Cr based alloy contains less than 25% of noble metal, contains Cr, is strong and corrosion-resistant, has a very low price compared with precious metals such as gold, (crown) and bridge casting.

However, efforts have been made to reduce the use of Ni as much as possible in consideration of safety, because Ni-Cr alloy is harmful to human body when Ni is eluted by being exposed in the oral cavity. Recently, Ni- Efforts are underway to replace them with alloys.

An alloy system most widely used as a casting Co-Cr alloy has been used by embedding Mo and / or W in a Co-Cr system, and has been used as an example of a well-known Co-Cr-Mo alloy. Co 62.55 By weight of Cr, 27.00% by weight of Cr, 6.00% by weight of Mo, 2.00% by weight of Ni, 1.00% by weight of Fe, 0.60% by weight of Si, 0.60% by weight of Mn and 0.25% by weight of C alloy.

In addition, we use non-precious metal alloys for pacification dentures, which are removed and fixed in the dental prosthetic field. Bego (Germany) and Jelenco (Germany), which are major manufacturers of cast partial dentures used in dentures ), Dentsply Prosthetics (US), and Bredent (Germany) use alloys containing Si, Mn, Fe, Ta, C, and N as the Co-Cr-Mo system.

On the other hand, according to a study on the repair after the use of the pacial denture, the damage of the pacial denture frame and the breakage of the wire class (the ring part in Fig. 1) occupy the second and the third of the total repair demand, The fracture of the partial hardener may be caused by a design error. However, since the amount of elastic deformation of the casting hard alloy based on the widely used Co-Cr-Mo based alloy is not so large, The damage is also significant.

Mo, which is a main alloy element constituting the Co-Cr-Mo alloy, is less toxic to the human body than Ni, but is less biocompatible than metal elements such as Nb, Ti and Ta, From the viewpoint of eliminating toxic substances, it is necessary to develop an element-based alloy having better biocompatibility.

U.S. Published Patent Application 2004/129349 Japanese Patent No. 5846530

An object of the present invention is to provide a method for molding a cast steel which is excellent in casting composition and can reduce the amount of leaching of an element harmful to the human body, To provide a Co-Cr-Nb-based alloy.

In order to solve the above-described problems, the present invention provides a method of manufacturing a semiconductor device, comprising 60 to 61% by weight of Co, 28 to 30% by weight of Cr, 4 to 5% by weight of Nb, 2 to 4% The present invention provides a Co-Cr-Nb based alloy comprising 0.3 to 1% by weight of Mo, 0.5 to 1.5% by weight of Mn, 0.1 to 0.5% by weight of Ti and 0.1 to 0.5%

The Co-Cr-Nb based alloy according to the present invention has a casting flowability similar to that of gold (Au) having a very good main composition, because the existing main alloy component reduces the content of Mo and is based on Nb , The elution amount of an element harmful to the human body can be further reduced as compared with the Co-Cr-Mo alloy.

Further, since the Co-Cr-Nb based alloy according to the present invention can significantly reduce the damage occurring during the process of deforming the denture frame or the wire clasp resulting from the procedure or use when cast in a pacific tentacle, It is possible to increase the convenience and reduce the maintenance cost of the pachalhtener.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an image and a photograph schematically showing a denture frame and a pupil of a partial tentacle which is performed in the oral cavity. FIG.
FIG. 2 is a photograph showing a casting molten metal tilted to a casting mold for producing a Co-Cr-Nb based alloy according to an embodiment of the present invention.
Fig. 3 is a photograph of a cast product manufactured using the casting mold of Fig. 2;
FIG. 4 is a photograph of a specimen for corrosion test of a Co-Cr-Nb based alloy fabricated according to an embodiment of the present invention.
5 is an image of a mold used for casting an alloy according to a comparative example.
Fig. 6 is an image of a mold used for casting an alloy according to Example 1. Fig.
7 is an image of a denture frame (partial tentacle) made of an alloy manufactured according to Example 1 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

The inventors of the present invention have found that, compared with Co-Cr-Mo type alloys which are conventionally used for conventional crowd dentures, the elution amount of human harmful components The present inventors have found that the Co-Cr-Nb-based alloy proposed in the present invention can be used as a co-Cr- It has been found that the excellent casting and the reduction of the amount of the harmful components to be eluted and the destruction of the pachydermata can be significantly reduced, leading to the present invention.

The Co-Cr-Nb based alloy according to the present invention comprises 60 to 61% by weight of Co, 28 to 30% by weight of Cr, 4 to 5% by weight of Nb, 2 to 4% by weight of W, 0.5 to 1.5% 0.3 to 1% by weight of Mo, 0.5 to 1.5% by weight of Mn, 0.1 to 0.5% by weight of Ti and 0.1 to 0.5% by weight of C by weight.

When the content of cobalt (Co) is less than 60 to 61% by weight, it is difficult to realize the corrosion resistance and mechanical properties required for the dental Co-Cr alloy.

When the content of chromium (Cr) is not 28 to 30% by weight, it is difficult to realize the corrosion resistance and mechanical properties required for the dental Co-Cr alloy.

When the content of niobium (Nb) is less than 4% by weight, it is difficult to realize the mechanical strength required for the dental Co-Cr alloy, the main constitution and the dissolution resistance of the harmful ingredient to be realized in the present invention, It is difficult to balance the overall physical properties (casting strength, strength, extrusion resistance, resistance to cracking, etc.), and therefore, it is preferable that the content is 5 wt% or less.

When the content of tungsten (W) is less than 2% by weight, it is difficult to realize the mechanical strength required for a dental Co-Cr alloy. When the content of tungsten exceeds 4% by weight, the overall physical properties (casting, strength, Resistance, etc.), it is preferable to add 2 to 4% by weight.

The silicon (Si) improves the flowability of the molten metal and deoxidizes the molten metal and improves the denseness of the alloy. If it is less than 0.5% by weight, the effect is not sufficient. If it exceeds 1.5% by weight, However, it is preferably added in an amount of 0.5 to 1.5% by weight, which is adversely affected by the density of the alloy.

The molybdenum (Mo) is a component contributing to realizing mechanical properties such as corrosion resistance and abrasion resistance required for a dental Co-Cr alloy, and when it is added in an amount of less than 0.3% by weight, the effect of contributing strength is small, , It is preferable to add 0.3 to 1% by weight because it can increase the amount of harmful elements eluted.

The manganese (Mn) has a deoxidizing effect similar to silicon (Si) to suppress the formation of oxide inclusions, thereby improving the fatigue strength of the alloy. When the content is less than 0.5% by weight, the effect can not be sufficiently obtained And 1.5% by weight, it is difficult to balance the overall physical properties of the alloy, and therefore, it is preferable that the additive is added in an amount of 0.5 to 1.5% by weight.

The titanium (Ti) serves as a deoxidizing agent to minimize the oxygen concentration upon dissolution. When the amount is less than 0.1% by weight, the deoxidizing effect is not sufficient. When the amount exceeds 0.5% by weight, 0.5% by weight.

The carbon (C) can serve to improve mechanical properties and refine the solidification structure in the casting process. If it is less than 0.1% by weight, the above effect can not be sufficiently obtained. If it exceeds 0.5% by weight, The amount thereof is excessively large and can be brittle, so that it is preferably added in an amount of 0.1 to 0.5% by weight.

[Example 1]

(1 wt%), Mo (0.5 wt%), Mn (1 wt%), Ti (1 wt%), Co (60.5 wt%), Cr (29 wt%), Nb (0.2% by weight) and C (0.24% by weight) are laminated in the air induction melting furnace in the order of low melting point alloy and high melting point alloy, and then melted to 1600 占 폚.

A molten alloy was injected into a round casting type precision casting mold shown in Fig. 2 to cut and grind the castable product to obtain a metal casting mold as shown in Fig.

[Example 2]

Example 1 In the same manner as in Example 1 except that the carbon content was increased to 0.30 wt% in the alloy, a cast metal in a metal form was obtained in the same manner.

[Comparative Example]

For comparison with the present invention, a Co-Cr-Mo based alloy was cast in the same manner as in the present invention to obtain a cast metal in a metal form. In this case, the composition of the Co-Cr-Mo alloy used in the comparative example was 60.9 wt% of Co, 29 wt% of Cr, 5 wt% of Mo, 2.3 wt% of W, ), Mn (0.7 wt%), Al (0.6 wt%), Ti (0.2 wt%) and C (0.3 wt%).

Evaluation of corrosion resistance

Corrosion resistance (resistance to ingress of harmful elements) of alloys prepared according to the examples and comparative examples of the present invention was evaluated by the Institute of Life Science, Seoul National University Dental Hospital. The corrosion test was carried out in accordance with ISO 22674: 2016 (E), and FIG. 4 shows the shape of the sample used for corrosion resistance evaluation.

- Sample surface area: 10.2 cm 2

- Corrosive solution: 10.0 ± 0.1g Prepare 300 ml of 90% lactic acid (C ₃ H ₆ O ₃ ) (10.0 ± 0.1) g and sodium chloride (NaCl) (5.85 ± 0.05) g and dilute to 1000 ml. A solution of pH (2.3 ± 0.1)

- Corrosion time: Put the specimen in the container, add the same amount of the corrosion solution to the surface area, maintain it at 37 ℃ for 7 days

- The amount of metal ion emission: The total sum of dissolution amount of Co, Cr, Mo, Nb, Fe, Si, Mn, W, Be, Cd,

- Evaluation Criteria: Total release of metal ions should be within 200 μg / ㎠

Table 1 below shows the results of the corrosion resistance evaluation as described above.

Item Example 1 Example 2 Comparative Example Metal ion emission amount
(占 퐂 / cm2) 54.3 60.4 69.9

As shown in Table 1, the alloys according to Examples 1 and 2 of the present invention and the alloys according to the comparative examples satisfied the total discharge amount of metal ions as acceptance standards within 200 占 퐂 / cm2, It can be seen that the alloy according to Example 2 is lower than that of the comparative example and the harmfulness to the human body is lowered.

Cytotoxicity test

The cytotoxicity test was conducted in accordance with Article 5 (ISO 10993-5) of the Food and Drug Administration Notice No. 2014-115, Medical Device Biosafety at the Dental Medical Device Testing and Evaluation Center, Yonsei University. Respectively.

1) The suspension of L-929 cells was dispensed into a 100-mm petri dish at a rate of 10 mL (2.5 × 10 ⁵ cells / mL) and cultured in a 5% CO ₂ incubator at 37 ° C. for 24 hours

2) Confirm the cell monolayer culture condition (over 80% of culture container area) and cell morphology by microscope

3) Remove the culture medium and slowly inject the RPMI 1640 Agar medium (RPMI 1640 (2X): Agar = 5.5) containing serum into the wall by about 10 mL

4) When the agar is hardened, dilute the solution with 10 mL of Neutral red (PBS = 300uL: 10 mL), seal it, and incubate it in a CO ₂ incubator

5) Remove the dye after checking whether it is dyed with a microscope

6) The test group and the negative and positive control specimens were placed on the stained agar. The size of the specimen was about 10/1

7) Culture in a CO ₂ incubator for 24 hours

8) Qualitative cytotoxicity after removal of specimen

As a result of the evaluation as described above, the degree of cytotoxicity of the alloy according to Example 1 of the present invention was evaluated to be '0' and no cytotoxicity.

Evaluation of mechanical properties

The mechanical properties of the alloys prepared in accordance with the embodiments of the present invention were evaluated by tensile test. In the tensile test, six rod-shaped specimens were produced on the basis of the method specified in ASTM A370-15, and the average values of the results of the respective tensile tests were evaluated by physical properties. The results are shown in Table 2 below.

Example 1 Dental alloy (Type 5)
standard Yield strength (MPa) 601 500 Tensile Strength (MPa) 918 - Elongation (%) 4 2 or more Elastic modulus (GPa) 206 150 or more

As shown in Table 2 above, the alloys according to the embodiments of the present invention have mechanical properties that are far superior to the standard requirements of the dental alloys (Type 5) used for the paclitane doughcher.

Casting  evaluation

The casting compositions of the alloys according to Example 1 of the present invention and the alloys according to the comparative examples were qualitatively evaluated.

Fig. 5 shows a mold of an alloy according to a comparative example and a state after casting. As shown in FIG. 5, a large amount of metal scum remains in the mold after casting, which indicates that the casting flowability of the alloy according to the comparative example is poor.

6 shows a mold of an alloy according to Example 1 and a state after casting. As shown in Fig. 6, after the casting, substantially no metal scum remains in the mold, indicating that the casting flowability of the alloy according to Example 1 of the present invention is remarkably superior to that of the comparative example.

Classp Fracture  evaluation

In the evaluation of the fracture property of the class, first, a partial hardener of the type as shown in Fig. 7 is manufactured, and then the deformation is repeatedly applied to the extent of deformation in the actual operation procedure by hand, and then the number of deformation until fracture occurs is measured The results are shown in Table 3 below.

Item Example 1 Comparative Example Class up to Fasson
Number of transformations 8 times 3rd time

As shown in Table 3, the alloy according to the present invention has a greater number of deformations up to the class F loss than the alloy according to the comparative example, thereby greatly reducing the possibility of fracture during the procedure or use.

Claims (2)

Co: 60 to 61% by weight,
28 to 30% by weight of Cr,
Nb: 4 to 5% by weight,
W: 2 to 4% by weight,
0.5 to 1.5% by weight of Si,
Mo: 0.3 to 1% by weight,
Mn: 0.5 to 1.5% by weight,
0.1 to 0.5% by weight of Ti,
C: 0.1 to 0.5% by weight of Co-Cr-Nb based alloy. The method according to claim 1,
The Co-Cr-Nb-based alloy is characterized in that the Co-Cr-Nb-based alloy is for a partial hardener.

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