JPS6048579B2 - Dental colorfast low karat yellow reinforced gold alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dental double rat gold alloy used as a casting alloy for crown restoration, metal floors, etc.

Conventionally, this kind of couple rat gold alloy often contains copper, and as a result, the surface of the cast body tends to turn black, which requires a great deal of time and effort to remove, and moreover, it requires the use of powerful cleaning agents. It is dangerous because it requires the use of similar substances, and it also has disadvantages such as requiring pollution prevention measures such as wastewater treatment.

On the other hand, the original applicant filed the patent application No. 56-95969 (Japanese Unexamined Patent Publication No. 57-21093) on June 23, 1982.
As shown in Publication No. 7), the weight ratio of gold is 0.5 to 22.
It was discovered that the above-mentioned drawbacks can be overcome by removing copper and adding indium to a couple rat gold alloy of up to 10%, and patented such an alloy. However, those alloys
In the oral cavity, where the self-cleaning effect is within reach, the expected color fastness is exhibited, but in areas where the self-cleaning effect is not, the discoloration resistance has been found to be insufficient in many subsequent examples over a considerable period of time. It became clear from the investigation.

Additionally, there is a demand from general clinicians for an alloy with heat treatment hardenability and a strengthened golden color that can further enhance the mechanical strength of this seed alloy. This invention is an improvement made in view of the above-mentioned circumstances, namely, the casting surface of the cast body is not scaled, and regardless of whether the self-cleaning effect reaches or does not reach in the oral cavity, To provide a yellow reinforced gold alloy that does not contain copper and always exhibits excellent discoloration resistance and has both the necessary workability and toughness through heat treatment.

This invention will be explained in detail below.

Table 1 shows the composition and properties of the alloy according to the invention. As is clear from this table, the alloy according to the present invention has a clear effect of heat treatment, and has a strength that is easy to process when softened, and a considerable increase in strength when hardened, and it is not affected by occlusal pressure. It has characteristics that are durable and suitable for use in bridges, etc. In addition, the results of color fastness tests at the laboratory stage have been very good. Cast bodies for dental crown restoration made using the alloy according to this invention do not cause blackening of the skin, and therefore surface cleaning of these cast bodies is extremely easy and does not require the use of powerful drugs. Since there is no need to do this, it is safer and the process has been simplified.

After polishing, the cast tooth crown restoration had a beautiful golden color that is not seen in other low-strength rat gold alloys of this type. Furthermore, this cast dental crown restoration is installed in the patient's oral cavity,
After several months of practical testing, we found that discoloration was observed not only in areas where the self-cleaning effect was effective, but also in areas where the self-cleaning effect was not effective, and the result was that the product remained as aesthetically pleasing as when it was first installed. It had an agricultural, slightly yellowish gold alloy appearance. The basis for limiting the range of various components of the gold alloy of this invention is as follows.

The gold is in the range of low-strength rat gold alloys that are desired for dental and other uses, increasing the precious metal properties of the silver alloy, and improving the necessary aesthetics, corrosion resistance, mechanical strength, operability, etc. However, in order to highlight the golden color that is the main component of aesthetics, we decided to add more than 22% (hereinafter referred to as weight ratio). If it is less than 22%, the golden color will be somewhat poor, and if it is more than 42%, it is outside the scope of the low-strength rat-based gold alloy that is the object of this invention, that is, the range including physical properties, color tone, price, etc., and was therefore excluded.

Palladium is an element that is effective in increasing the sulfidation resistance of silver alloys, and is also added as an element that helps improve noble metal properties and mechanical properties, but if the amount added is small, the sulfidation resistance of the alloy will be reduced. If sufficient amount is not obtained and the amount added exceeds the limit, the melting temperature will increase, the amount of gas absorbed will increase, and the lack of toughness in terms of strength will occur. 5% to 35%.

Note that up to 112 amounts of this palladium can be replaced with other elements of the white metal. 3. Indium lowers the melting temperature of the gold alloy of the present invention, compensates for the lack of improvement in color fastness and corrosion resistance due to gold and palladium, and acts on the homogeneous solid solution phase of the gold-silver-palladium system to improve the alloy. In addition to improving strength, it also provides heat treatment hardening properties, and when softened, 3. In addition to making workability easier, it can withstand occlusal pressure and wear when hardened, and can be used for bridges, hooks, bars, etc.
The range is set to be effective in providing the necessary strength and hardness to floors, etc.

The addition of indium also serves as a factor in preventing the skin color of the cast body from turning black. For these 4C reasons, the amount of indium added is set at 5 to 18%, but if it is less than 5%, it will lower the melting temperature of the real gold alloy, prevent the skin color of the cast body from turning black, and improve the discoloration and corrosion resistance. If the heat treatment hardenability etc. is not sufficiently obtained, and if it exceeds 18%, the castability will deteriorate more than expected and the strength will become weaker, making it unsuitable for actual use. Valent lead is generally widely used as an effective element for deoxidizing this type of alloy, but if the amount added is small, it will not be effective as a deoxidizing agent.
If it is too large, the flow of the alloy will be poor, the color tone of the alloy will be impaired, and the toughness will be lost, so the effective range is 0.1.
~10%.

As described above, the gold alloy according to the present invention has extremely excellent discoloration resistance not only in the areas where the self-cleaning effect is applied in the oral cavity, but also in areas where it is not, and even though it is a low-strength rat and does not contain copper. It is an extremely useful dental alloy as it is a gold alloy with heat treatment hardenability, strengthened yellow color, and does not cause blackening of the casting surface of the cast body, and its utility value is remarkable.

Note: (Softening) After heating at 85°C and holding for m minutes, quench in water.

(Curing) After the above-mentioned softening treatment, it was heated and held for 450'ClO minutes, and then lowered to 200°C over 3 minutes, and then left to cool in the atmosphere.

Claims (1)

[Scope of Claims] 1. Dental discoloration, characterized in that the weight ratio is more than 22% to 42% gold, 5 to 35% palladium, 5 to 18% indium, 0.1 to 10% zinc, and a residual amount of silver. Low carat yellow reinforced gold alloy.