JPS6041694B2 - dental alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dental alloy with a low melting point and excellent castability, and particularly to a dental magnetic alloy suitable for use in combination with a rare earth cobalt magnet.

The idea of using permanent magnets in the dental field has been around for a long time, and attempts have been made to maintain the stability of dentures by using the attractive and repulsive force of magnets, but this has not been put to practical use.

However, in recent years, with the advent of extremely small and powerful rare earth cobalt magnets, this has become a reality for the first time. A recent trend in denture technology is to utilize remaining teeth as much as possible. Supplementary denture maintenance methods using permanent magnets are in line with this trend, and are being actively researched at various universities. Clinical experiments at various universities have yielded good results to date, and there is a strong expectation that this technology will be perfected as a new method for dental prosthetics in the future and will be used by general clinicians. FIG. 1 shows the root plate method, which is known as one of the basic methods of magnetic prosthesis.

When this method is applied to complete dentures, tooth loss can be prevented.
In addition to the superior feel of the device as it can be made palatal, compared to other attachments such as clasp and hook types, it does not put too much force on the remaining teeth and reduces occlusal pressure. It has features such as being clean and preventing alveolar pyorrhea. By the way, for example, in the above method, as shown in FIG. 1, the rare earth cobalt magnet 5 magnetizes the
A magnetic alloy 3 having sufficient attractive force with the magnet 5 is used.

In addition to magnetic properties, the magnetic alloy used here must also have workability for dental casting, and must also have physical, mechanical, and chemical properties that are necessary for dental casting. It is preferable that the material is also excellent in properties. As dental soft magnetic alloys that meet the above requirements, CO-Pd and Ni-Pd, which were previously proposed by the applicant (Japanese Patent Application No. 126145/1982 and No. 12206/1983), are
There are alloys whose main components are This alloy has a melting temperature of 1
At 350℃ or less, the saturation magnetic flux density is 200? That's all,
It is a dental magnetic alloy with excellent corrosion resistance. However, the above-mentioned CO-Pd alloy and Ni-Pd alloy have inferior castability compared to Au-Ag-Pd alloy, which is commercially available as an alloy for dental casting, and dental technicians do not actually use centrifugal casting machines. When casting, a slag-like thin film forms on the entire surface of the melt, making it difficult to determine the timing of casting.

An object of the present invention is to solve the above-mentioned problems, make it easier to determine the casting timing, and provide a novel dental magnetic alloy that has excellent castability.

In order to achieve the above object, the present invention provides a weight ratio of Pd2
8-75%, SI 5% or less, CO or Ni2O-7
0%.

In the present invention, the reason why CO or Nj is set to 20 to 70% is to set the melting temperature to 1350°C or less,
Further, by forming an alloy with Pd, a magnetic alloy with high corrosion resistance can be obtained.

S1 improves castability and significantly reduces cavities.

Moreover, the effect is particularly remarkable at 0.1% or more. On the other hand, if the amount of Si exceeds 5%, the material becomes extremely brittle, so the amount of Si added should be 5% or less. Hereinafter, the present invention will be explained in detail based on examples. Example 1 By weight, 43% Pd-57% CO and 43% Pd-
0.5% for 100% alloy with a composition of 57%Ni
of Si was added and alloyed in an argon arc melting furnace.

20 x 20 x 0.3T to observe pouring rate and cavities.
17A and 4? A φ×1 wax pattern was prepared. Cerabest was used as the investment material, and after dewaxing, the alloy was melted and cast using a high-frequency induction centrifugal casting machine at a preheating temperature of 800'C. In a similar manner, 43%Pd-57%CO
alloy, 43%Pd-57%Ni alloy and commercially available Au-
Ag-Pd alloys were cast to compare casting rates and cavities. As a result, no difference was observed in the pouring rate among the five types of alloys, but the number of cavities in the alloy to which Si was added was drastically reduced.

In addition, regarding the casting timing, alloys containing Si have the effect of damaging the slag film that coats the melt surface, and the movement of the melt surface can be directly observed, making it easy to judge. . Example 2 A Pd-CO-Ni alloy having the composition shown in Table 1 in terms of weight ratio and an alloy in which Si was added to 100% Pd-CO-Ni alloy were melted and cast in an argon arc melting furnace, and their various properties were melted and cast. We investigated the characteristics.

The results are shown in Table 1. From Table 1, it is clear that the alloy of the present invention is a magnetic alloy with a low melting point and excellent castability.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a magnetic prosthesis method using a root plate method. 1: Gum part, 2: Root part, 3: Magnetic alloy, 4: Denture, 5
: Rare earth cobalt magnet.

Claims (1)

[Claims] 1. A dental magnetic alloy comprising 28-75% Pd, 5% Si or less, and 20-70% Co or Ni by weight.