JPH111738A - Novel metal alloy for dental casting use, having property of bonding to ceramic material by baking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alloy excellent in corrosion resistance in the oral cavity, having such a low melting point that metal frame casting by the use of a gypsum-type embedding material is enabled, and excellent in strength and property of bonding to a ceramic material by baking. SOLUTION: This alloy has a composition consisting of, by weight, 19-20% Au, 19-30% Pd, 9-20% Cu, 0.02-0.03% lr, 0.5-4.5% Sn, 0.5-4.5% Ga, 33-48% Ag, and inevitable impurities and satisfying Sn+Ga=2 to 5%. The alloy can enable metal frame casting by the use of a gypsum-type embedding material and has a low melting point. Further, the alloy has excellent corrosion resistance as well as excellent strength and property of bonding to a ceramic material by baking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porcelain baked noble metal alloy for dental casting which is used as a base casting material for porcelain baked artificial teeth for the purpose of reinforcing the strength of porcelain for restoration. is there.

[0002]

2. Description of the Related Art A porcelain baked noble metal alloy for dental casting, which has been used as a base casting material for porcelain baked artificial teeth for the purpose of reinforcing the strength of porcelain for restoration, has been put into practical use around 1970. Things.

[0003] In the past, in the restoration of crowns, cast materials of precious metal alloys were used. However, as the method of using porcelain materials has been developed, compatibility with living bodies, chemical stability, and high durability have been improved. In addition to abrasion, etc., the restoration of the crown using a porcelain close to the natural body has been favored by patients, particularly from the aspect of aesthetics, and many restoration procedures using the porcelain have been performed. .

However, porcelain for crown restoration has a basic composition of feldspar-based, and looking at the main components of commercially available products, feldspar is 80 to 90% by weight and quartz is 10% by weight%.
~ 15%, kaolin 0 ~ 5%. Therefore,
It can be said that the porcelain for crown restoration has the above advantages, but has weak points in terms of tensile strength, bending strength and impact resistance.

As a means of compensating for these weaknesses and satisfying the needs of patients, a technique of restoring a crown by veneering porcelain on a pre-fabricated metal frame has been developed.
Has been put to practical use. Metal alloys having various compositions have already been reported as alloys for producing metal frames used in this case.

Here, the material characteristics required for the porcelain baking alloy can be summarized as follows. That is, 1. The solid phase point of the metal material must be equal to or higher than the firing temperature of the porcelain so that the shape is maintained when the porcelain is fired. 2.
It should be well connected with porcelain so that the repaired crown can be used for a long time. 3. When firing porcelain, high-temperature strength must be high so as not to deform the porcelain. 4. When baking porcelain, there should be few components that would color the porcelain. 5. The elastic coefficient and elastic limit must be large so that there is no risk of deformation even when the metal material is provided as thin as possible and used thin. 6. In order to enhance the seizure with the porcelain when the restoration crown is used for a long period of time, the thermal expansion coefficient of the metal material is similar to that of the porcelain.

At present, as a precious metal material for baking porcelain,
In terms of% by weight, for example, Au is 39.0%, Pt is 1.0%, Pd is 35.0%, Ag is 19.4%, Sn
Alloy with 5.0%, Au with 88.0% and Pt with 4.5%
%, Pd is 6.0%, and Ag is 0.5%.

However, these alloys have a high liquidus point of 1250 ° C. and 1170 ° C., respectively, and are relatively easy to handle as investment materials when casting a metal frame for baking porcelain in veneer form. Only difficult phosphate investment is available. Also, in order to form a metal frame by casting using an alloy having a high liquidus point, it is necessary to perform the casting operation of the alloy at a temperature 100 to 150 ° C. higher than the liquidus point. Therefore, utilization of city gas-oxygen flame or high-frequency induction heating furnace is indispensable. In the operation, consideration must be given not only to high-temperature operation but also to management of handling gas and high-voltage power supply.

Further, when casting is performed at a high temperature, the surface of the cast product and the investment material tend to react with each other, whereby the surface of the cast product is easily deformed or roughened.

Further, as an alloy which can be cast at a low temperature, expressed by weight%, for example, Au is 12.0% and Pd is 2%.
An alloy containing 0.0%, 40 to 49% of Ag, 20% of Cu, 17 to 20% of In, and 0 to 4% of Zn is exemplified. However, although this alloy has a low solidus point of 912 ° C. and enables a metal frame casting using a gypsum-based investment material as desired, the hardness is Vickers hardness.
The corrosion resistance in the oral cavity is low, and the development of an alloy having a more preferable composition is desired.

On the other hand, as the porcelain for crown restoration itself, porcelain which requires a lower firing temperature than conventional porcelain has come to be sold. Therefore, the alloy used to form the metal frame for baking porcelain can also use city gas and atmospheric flame as a heat source, and has a low melting point that enables casting work using gypsum-based investment material. The development of alloys is urgently needed.

If the gypsum-based investment material can be used, not only can the time required for the casting operation of the metal frame be significantly reduced, but also the release operation of the cast product cast into the investment material becomes easy. On the other hand, a metal frame having an extremely fine surface roughness of a cast product and excellent reproducibility in detail can be easily obtained.

[0013]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned difficulties, has excellent corrosion resistance in the oral cavity, and enables a metal frame casting using a gypsum-based investment material. Dental casting porcelain with excellent reproducibility of the details and surface roughness of the casting, easy work of removing the casting material from the mold, low melting point, and excellent strength and seizure with porcelain It is intended to provide a baked noble metal alloy.

[0014]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted various experiments, and as a result, by adding Sn and Ga or Sn + Ga + In to a noble metal alloy together, Without impairing the yield strength and hardness of porcelain baked precious metal alloy for dental casting, rather improve it,
It has been found that it is possible to reduce the melting point of the alloy and make it possible to use a gypsum-based investment material in the production of a cast metal dental frame. Based on this, it has been found that the problem can be solved by an alloy composition as described below, and the present invention has been provided.

That is, the porcelain baked noble metal alloy for dental casting according to the present invention comprises, as a first embodiment, 19 to 20% by weight of Au, 19 to 30% by weight of Pd, and 9 to 20% by weight of Cu.
0.02% to 0.03% by weight of Ir and 0.4% to Sn
4.5% by weight, 0.5 to 4.5% by weight of Ga, and Ag3
3 to 48% by weight, and unavoidable impurities.
The content of Ga is 2 to 5 weight.

The present invention provides, as a second embodiment, Au1
8 to 30% by weight, Pd 18 to 29% by weight, Cu11
-20% by weight, Ir 0.01-0.04% by weight,
0.5-5.0% by weight of n and 0.5-6.0% by weight of Ga
And 0.5 to 5.0% by weight of In, 23 to 41% by weight of Ag, and unavoidable impurities, and the Sn + Ga + In content is 1.5 to 7.5% by weight.

The present invention provides, as a third embodiment, Au1
8 to 20% by weight, 23 to 29% by weight of Pd, and Cu11
-18% by weight, Ir 0.02-0.03% by weight, S
0.5-3.0% by weight of n and 0.5-3.0% by weight of Ga
And 0.5 to 3.0% by weight of In, 34 to 41% by weight of Ag, and unavoidable impurities, and the Sn + Ga + In content is 1.5 to 6.5% by weight.

The present invention provides, as a fourth embodiment, Au2
7 to 30% by weight, 18 to 29% by weight of Pd, and Cu14
-20% by weight, Ir 0.01-0.04% by weight,
0.5-5.0% by weight of n and 0.5-6.0% by weight of Ga
And 0.5 to 5.0% by weight of In, 23 to 25% by weight of Ag, and unavoidable impurities, and the Sn + Ga + In content is 1.5 to 7.5% by weight.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Au-Pd-Cu of the present invention
An alloy in which Sn and Ga are added to an Ir-Ag-based alloy, and the second embodiment is Au-Pd-Cu-Ir.
-An alloy obtained by adding Sn, Ga, and In together to an Ag-based alloy. In a third embodiment, an Au-Pd-Cu-Ir-Ag having an Au content of 18 to 20% by weight is used.
The fourth embodiment is an alloy in which Sn, Ga, and In are added to a system alloy, and the fourth embodiment has an Au-Pd-Cu-Ir-Ag system alloy having an Au content of 27 to 30% by weight. S
This is an alloy in which n, Ga, and In are added together.

In this case, Au is highly compatible with living organisms,
Pd is used to obtain an alloy with excellent corrosion resistance.
Is used to reduce the coefficient of thermal expansion of the alloy and increase the strength, Cu is used to increase the strength of the alloy, and Ir refines the crystal grains and simultaneously increases the strength and elongation of the alloy. Ag is used for cost reduction, and Sn and Ga, or Sn, Ga, and In are used to reduce the liquidus point of the alloy and to enhance the seizure of the porcelain and the alloy. Used for

However, when Au is added in a large amount, it becomes expensive in terms of price and relatively low strength can be obtained in terms of strength.
%, And in the second and fourth embodiments, 30% by weight.
Is the upper limit for each. When Pd is added in a large amount, it tends to increase the liquidus point to disable the use of gypsum-based investment material, or to lower the thermal expansion coefficient of the alloy to lower than that of porcelain, thereby lowering the seizure of porcelain. Therefore, the upper limit is 30% by weight in the first embodiment, and 29% by weight in any of the second, third, and fourth embodiments. If Cu is added in a large amount, corrosion resistance tends to cause a problem. Therefore, the upper limit is 18% by weight in the third embodiment, and 20% by weight in each of the first, second and fourth embodiments. And Even if Ir is added in a large amount, its effect immediately saturates. Therefore, in the first and third embodiments, the upper limit is 0.03% by weight, and in the second and fourth embodiments, The upper limit is 0.04% by weight. Also, Sn + G
When a or Sn + Ga + In is added in a large amount, the strength of the alloy is lowered and the alloy becomes brittle. Therefore, in the first embodiment, 5% by weight of Sn + Ga is added in the third embodiment. , 6.5% by weight of Sn + Ga + In,
In the fourth embodiment, the upper limit is 7.5% by weight of Sn + Ga + In.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail below with data.

Example 1 19.61% by weight of Au and P
d. 19.61% by weight, Cu 9.5% by weight, Ir0.
02% by weight, Sn 4.3% by weight, and Ga 0.5% by weight
And an alloy containing 47.48% by weight of Ag were melted in a quartz tube under an argon atmosphere using a high-frequency induction heating furnace, and cooled and solidified to obtain an ingot.

Various test pieces were cut out from the above ingot by a predetermined amount, melted using city gas / air flame, and cast into a mold prepared using “Cristopalite Micro” manufactured by GC Corporation. I got In this case, “Cristopalite Micro” manufactured by GC Corporation is a gypsum-based investment material. The above-mentioned various test pieces are referred to as “Dental ceramic fused to
metal restorative material
ls ”are various test pieces necessary for performing various tests specified in“ ls ”. In addition, for each of the above test pieces, according to the measurement method specified in the above standard, in accordance with the seizure between the porcelain material and the alloy, the melting temperature, coefficient of thermal expansion, proof stress, elongation, and hardness of various alloys. Was measured.

The seizure test between the porcelain and the alloy was measured as follows. That is, the raw materials were melted using a high frequency induction heating furnace placed in an argon atmosphere, and the total amount was 3
15 g of ingot was melted. Among them, 40 g of the alloy was cut out from the ingot, melted using city gas and air flame, and centrifugally cast into a mold prepared using gypsum-based investment material “Cristopalite Micro” manufactured by GC Corporation. The substrate was poured by a method to prepare a seizure test substrate having a length of 20 mm, a width of 5 mm, and a thickness of 0.4 mm. The surface for the seizure test was subjected to a cleaning treatment in accordance with the porcelain building method described later in detail, and then the opaque ceramic was treated with 0.3%.
mm thick, then dentin ceramic,
An enamel ceramic was overlaid, the total thickness of the ceramic portion was adjusted to 1.0 mm, and a seizure test specimen according to ISO regulations was prepared. An iron bar having a diameter of 10 mm was applied to the surface opposite to the surface of the seizure test piece on which the ceramic was built, that is, the central portion in the longitudinal direction of the exposed surface of the seizure test substrate. The seizure test piece was bent along the outer peripheral surface. In this case, the bending was stopped at a position where both ends of the seizure test piece showed 90 degrees. Once, the seizure test piece whose both ends were bent to a position showing 90 degrees was bent back to the original position by a pressing jig and adjusted to a flat state. Here, by observing the porcelain laying surface of the seizure test specimen prepared in the original flat state, and by categorizing the peeling state of the porcelain laid on the surface, the ceramic and the seizure test substrate were categorized. Was examined for seizure.

In this case, the ratio of the ceramic remaining in the portion corresponding to the central part 1/3 of the seizure test piece exceeds 50%, and the number of the seizure test pieces satisfying this is less than 50%. This alloy was judged to have good seizure performance when it was 4 or more out of 6 samples.

In the case of the present alloy having the above-described composition, after being subjected to a predetermined bending process, the seizure with the ceramic is evaluated based on the area of the porcelain remaining on the surface of the alloy.
0% was obtained, and it was confirmed that this value satisfied the standard.

In this case, Dentsply's “Multimat Mach 2” is used as the porcelain baking device, and “Degceram Gold” made by Degussa is used as the porcelain, and the following five steps are performed according to the manufacturer's instructions. Heat baking treatment was performed to prepare a seizure test piece between the porcelain material and the alloy.

1) Oxide film formation treatment Cast into a predetermined shape of 20 mm × 5 mm × 0.4 mm
After cleaning the surface of the seizure test substrate molded to the dimensions of above, in a vacuum between 450 ° C. and 800 ° C.,
Heat at a rate of 55 ° C. per minute, hold at 800 ° C. for 10 minutes, then quench.

2) Opaque treatment An opaque ceramic of "Degceram Gold" manufactured by Degussa Co., Ltd., as a porcelain material, having a build-up thickness of 0.3 mm was placed on the substrate for the seizure test after the treatment of item 1 above. It is preliminarily dried at 450 ° C. for 4 minutes in a vacuum, and then heated at a rate of 55 ° C./min to 780 ° C. in a vacuum to 780 ° C. And then quench.

3) Primary dentin treatment On the seizure test substrate, which has been subjected to the treatment described in the above item 2, a dentin ceramic of "Degceram Gold" manufactured by Degussa Co., Ltd. is used as a porcelain material. It is applied to a thickness of 6 mm, preliminarily dried at 450 ° C. in vacuum for 9 minutes, and then heated in vacuum to 780 ° C. at a rate of 55 ° C./min. , And then cooled to 720 ° C, then from 720 ° C to 680
After cooling between ℃ for 4 minutes, it is allowed to cool in the air.

4) Secondary dentin treatment On the substrate for the seizure test after finishing the treatment of item 3, as a porcelain material, an enamel ceramic of "Degceram Gold" manufactured by Degussa Co., Ltd., having a build-up thickness of 0 .1 mm, pre-drying at 450 ° C. in vacuum for 9 minutes, and then heating in vacuum to 780 ° C. at a rate of 55 ° C./min. After holding at 1 ° C. for 1 minute, the mixture is rapidly cooled.

5) Glazing Treatment A glaze material of "Degusceram Gold" manufactured by Degussa Co., Ltd. is applied as a porcelain material on the substrate for the seizure test after the treatment of item 4 and then heated to 450 ° C. in vacuum. Preliminary drying is performed for 4 minutes, followed by heating in vacuum at a rate of 55 ° C./minute up to 780 ° C., holding at 780 ° C. for 1 minute, and then rapidly cooling.

Further, as specified in the ISO 9693 standard, the iso-solid point and the iso-liquid point of the alloy by differential thermal analysis are measured by a measuring method using a cooling curve, respectively. 880 ° C. and an isoliquid phase point of 1020 ° C. were obtained. This temperature is said to be a temperature at which casting can be performed with a gypsum-based investment material.
It was below 0 ° C.

Further, the previously adjusted diameter 6 mm and length 2
Using a 0 mm cast material test piece, measurement of the coefficient of thermal expansion specified in ISO 9396 was performed using a thermomechanical analyzer. In this case, the sample was heated between 25 ° C. and 500 ° C., and the isothermal expansion coefficient of the alloy was determined. As a result, 15.9 × 10 ⁻⁶ K ⁻¹ was obtained. This value is one of the coefficient of thermal expansion described in the catalog of “Degusceram Gold” manufactured by Degussa, which is commercially available as a low-temperature dental ceramic for dental use.
Compared to 5.8 × 10 ⁻⁶ K ⁻¹ , slightly
^It showed only a difference of ^-6 K ^-1 , indicating that the seizure between the porcelain and the alloy was kept excellent.

Further, the diameter is 3.0 mm and the distance between gauges is 15
mm, using a cast material specimen with a threaded grip,
A tensile test according to the 6892 standard was performed, and a 0.2% offset proof stress was determined from the drawn stress-strain curve. In this case, the proof stress value is 600 MPa, and ISO 969
It shows a value that greatly exceeds the minimum proof stress value 240 MPa specified in the 3 standards.

At the same time, the elongation of the alloy was measured by a method according to the ISO 6892 standard. As a result, the measured elongation after tensile fracture was 5%, exceeding the minimum elongation value 3% specified in the ISO 9693 standard. The values conform to the ISO standard.

At the time of casting the above-mentioned substrate for seizure test, a 10 mm × 10 mm × 1 m
After giving the same thermal history (without coating of porcelain) as in the case of the above-mentioned seizure test substrate, the hardness of the surface of the m test piece was measured by Vitzkers hardness. , 220 were obtained as the measured values.

Further, the alloy of the present invention was melted with city gas / air flame, and the molten metal was used as a gypsum mold with a gypsum-based investment material “Cristopalite Micro” manufactured by GC Corporation. As a result of a test on the feasibility of using a gypsum-based investment material, it was found that the casting treatment of the alloy of the present invention can be performed without any trouble even if the gypsum-based investment material is used.

The test results measured in the same manner as in Example 1 except that the alloy composition was changed in accordance with the above test results are shown in a list in Tables 1 to 6.

In this case, Tables 1 and 2 show the test results of the first embodiment and a comparative example thereof, and Tables 3 to 6 show the second to fourth embodiments and the test results thereof. The test result by a comparative example is shown.

As is apparent from the above, the alloy of the present invention is:
As a porcelain baked noble metal alloy for dental casting, we provide an alloy with excellent functions that has extremely good seizure with porcelain, excellent strength, and also enables the use of gypsum-based investment materials. I can do it.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

[0048]

[Table 6]

[0049]

According to the present invention, it has been shown that a gypsum-based investment material can be used as an investment material, which is excellent in seizure with porcelain, has excellent strength and corrosion resistance, and can be used as a casting material. It is possible to provide a porcelain baked noble metal alloy for dental casting, which also has a smooth surface of the frame.

The use of this alloy makes it possible to produce porcelain close to a natural body in addition to compatibility with living organisms, chemical stability, high abrasion resistance, etc., and especially excellent aesthetics. The restoration of the crown to be performed can be processed quickly, precisely and easily.

Claims (4)

[Claims] (1) Au: 19 to 20% by weight and Pd: 19 to 3
0% by weight, 9 to 20% by weight of Cu, 0.02% of Ir
0.03% by weight, Sn 0.4 to 4.5% by weight, Ga
0.5 to 4.5% by weight, 33 to 48% by weight of Ag, and inevitable impurities, and the Sn + Ga content is 2 to 5%.
A porcelain baked noble metal alloy for dental casting, characterized in that the content is by weight. 2. 18 to 30% by weight of Au and 18 to 2% of Pd.
9% by weight, Cu 11 to 20% by weight, Ir 0.01 to
0.04% by weight, Sn 0.5 to 5.0% by weight, Ga
0.5 to 6.0% by weight and In 0.5 to 5.0% by weight
And 23 to 41% by weight of Ag and inevitable impurities, and the content of Sn + Ga + In is 1.5 to 7.5% by weight.
A porcelain baked noble metal alloy for dental casting, characterized in that: 3. Au 18 to 20% by weight and Pd 23 to 2
9 wt%, Cu 11-18 wt%, Ir 0.02-
0.03% by weight, Sn 0.5 to 3.0% by weight, Ga
0.5 to 3.0% by weight and In 0.5 to 3.0% by weight
And 34 to 41% by weight of Ag and inevitable impurities, and the content of Sn + Ga + In is 1.5 to 6.5% by weight.
A porcelain baked noble metal alloy for dental casting, characterized in that: 4. 27 to 30% by weight of Au and 18 to 2 parts of Pd.
9% by weight, Cu 14 to 20% by weight, Ir 0.01 to
0.04% by weight, Sn 0.5 to 5.0% by weight, Ga
0.5 to 6.0% by weight and In 0.5 to 5.0% by weight
And 23 to 25% by weight of Ag and unavoidable impurities, and the content of Sn + Ga + In is 1.5 to 7.5% by weight.
A porcelain baked noble metal alloy for dental casting, characterized in that: