JPS62298350A - Production of calcium phosphate crystallized glass tooth crown - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Tumor Application) The present invention provides a method for manufacturing a calcium phosphate-based crystallized glass dental crown, and in particular provides a highly accurate crystallized glass dental crown without deformation. It is related to the method.

(Conventional technology) In recent years, calcium phosphate glass has been used as a material to fill in tooth defects by swirl-forming and crystallizing it to create an appearance similar to that of natural teeth, and properties such as hardness and thermal conductivity that are similar to those of natural meat. It is suggested to get something close.

This method is for traditional gold, l14 casting and colleague 1, take it from the fool H! OT technology involves forming glass using a centrifugal casting method based on a wax pattern formed on a mold. However, as it is, glass is not preferable because it is transparent and has a different external surface from natural teeth, and is also brittle and, when broken, may form a sharp break and cause damage to the inside of the oral cavity.

Therefore, these defects can be prevented by heating to a predetermined temperature to effect crystallization to obtain crystallized glass.

The method of M crystallization is to perform it as it is in the 'A type,
There is a way to remove it from the mold.

(Problem to be solved by the invention) However, in the former method, the mold material and the glass react and stick together during casting, so mechanical stress is generated between the mold and the glass when forming a crystalline stone wall. This generates residual stress in the crystallized glass, deteriorating its mechanical strength and causing deformation of the tooth crown. In addition, the generation of crystal nuclei becomes uneven, and crystallized glass is preferable for homogeneity, and crystallization is performed with the runner part attached to the crown of the tooth.
There are problems such as traces of I-mail remaining.

On the other hand, in the latter method, although the above-mentioned problems do not occur, the glass softens during crystallization, and the peripheral edge becomes rounded due to deformation due to its own weight and six-fold tension. In the case of dental crown materials, the periphery seals off the area where tooth structure has been removed to prevent secondary caries! This is the part of the IK floor that requires particularly high dimensional accuracy, and deformation of this part poses an important problem.

(Means for resolving the problem) The present inventor took the molded glass out of the mold and cooled it to the point where it crystallized, without causing any substantive deformation.
As a result of extensive research and examination with the aim of finding a means to maintain a state with high dimensional accuracy, it was discovered that the above object could be achieved by performing crystallization using a specific support stand.

Thus, in the present invention, the inner surface of calcium phosphate glass cast in the shape of a tooth crown is used as an abutment tooth shaped so.
To provide a method for manufacturing a calcium phosphate-based crystallized glass dental crown, which is characterized in that crystallization is performed by forming an iron layer so as to be in close contact with the outer surface of a refractory that does not deform at temperatures below o'a.

The calcium phosphate glass used in the present invention contains at least 70 parts by weight of calcium phosphate, and has an atomic ratio of calcium to phosphorus, Ca/P, of 0.35 to 0.7.
Those within this range are preferable because they have appropriate melt hardness and d liquid viscosity that makes casting easy, have mechanical strength and chemical durability, and exhibit an appearance and hardness similar to natural teeth. .

If Ca/P exceeds 0.7, vitrification will be difficult, while if it is less than 0.35, not only will uniform crystallization be difficult to occur, but the phosphorus component will be excessive and durability will decrease. Therefore, 1c'l is not preferable either.

In the present invention, first, a glass bath is cast into a metal MW for dental use in the same manner as casting a metal material. That is, an impression is first taken from the formed abutment tooth, and based on this, a model of the abutment tooth is created using plaster.

Next, on top of this stone masonry model, we build up paraffin wax in the shape of a tooth crown to create a deaf ear.

A runner is provided in this mold using cylindrical paraffin wax, and a slurry-like investment material is injected around the periphery d. After the investment material has hardened, it is heat treated at 500 to 800°C to burn off the wax and create an operational mold. This investment material is in the form of a slurry,
Any material can be used as long as it is hardened by drying through a chemical reaction and the hardened product has a strength that does not collapse even when cast at a temperature of 500 to 800°C, such as phosphate thread, ethyl silicate, etc. I-)t''
L. For casting, methods such as the centrifugal casting method, compression conditioning method, true nitrogen compression casting method, etc. are used to maintain the mold at 500 to 800° C. and melt the glass in a bath. The glass is kept in the mold and cooled down to the temperature required to avoid rapid cooling.

Glass is removed from the investment material using a technical drill or a bottle set, but since glass before it hardens is quite brittle, sandblasting, in which glass beads are blown at a pressure of about 4 to 9, is used. Preferably, the method is used.

.

After a while, I cut the birth canal part of the glass and dyed it into a rectangular shape. However, the runners may not be cut if desired.

The molded glass is placed on the outside of the refractory whose inner surface is in the shape of an abutment tooth, thereby preventing deformation and making it R6.

There is no restriction on the refractory material as long as it can be molded into the shape of the abutment A and is stable at less than s o o 'o, but there are no restrictions on the refractory material, but there are no restrictions on the refractory material, as long as it can be molded into the shape of the abutment A and is stable at less than s o o 'o. The material is
Preferred examples include phosphate-based investment materials, ethyl silicate thread investment materials, and stone-based investment materials. Hard stone bone for the abutment tooth retainer is also suitable.

The preparation of the abutment for debt crystallization used in the present invention is performed, for example, as follows.

First, the impression of the abutment tooth is made directly from the imprinter or from the stone working model.

1. When making an impression directly from the patient, ordinary alginate 4 threads, rubber type, agar type, etc. can be used, and when making an impression from a stone model, the above impression materials can be used, but when casting wax is used, crystals from the mark tU can be used. This is particularly preferred since the wax can be removed by simply burning off the wax.

A refractory slurry is poured into the impression thus obtained and allowed to harden. After the refractory slurry has hardened, remove the abutment from the impression mold. However, if an impression mold is made with wax as mentioned above, this operation can be omitted.

The dk moat & lumber is fired according to the recipe to give it sufficient strength and form the support.

The glass dental crown is placed on the abutment thus obtained and heat treated to crystallize it.

At this time, since the inner surface of Ji7cf comes into contact with the abutment, it becomes a matte surface reflecting the surface condition of the abutment, but since it is only the inner surface, it does not affect the aesthetics at all; This has the advantage of controlling the adhesive strength when bonding. Incidentally, without removing all the investment material used when molding the glass crown, the investment material inside the crown can be made cheap and used as a large abutment, and the present invention also includes such a bad J5R. It is something that −
On the other hand, the outer surface of the crown has the advantage that it does not soften the glass during crystallization and has a smooth, glossy surface due to the surface elongation, which eliminates the usual grinding and polishing processes. There is.

(Implementation row) Actual m 12 s 1 A wax pattern is drawn from the abutment tooth stone q work model and 9.
Use this as a phosphate-based investment material (Blue Pest, manufactured by Keishan Kowaisha).
After K burial, the wax was burnt off by heating to ao o 'o to create a mold. Next, add 1300'O to this mold,
4PR@a CI! Phosphorus having a composition of 25% by weight of L0, 574% of P2O, and 12031g of phosphorus was prepared by centrifugation A of calcium-based glass.

This was placed together with the mold in an electric furnace maintained at 500'O, and
The barley was kept for a period of time and cooled to room temperature at a rate of 50'O/hr.

Next, it was blown onto glass beads 4 at a pressure of 9/-, and the glass member structure was taken out from the investment material. The runner was then cut and shaped using a grinder, making sure that there were no cracks, protrusions, or air bubbles.

Next, wax was applied to the abutment teeth of the working model used to create the wax pattern, a mold was taken of the abutment teeth, and a refractory (Tokuyama A slurry of Blue Pesto (manufactured by d Hensha) was poured in and heated to a hardening temperature of 800'o to incinerate the wax to obtain a support for crystallization.

The above-mentioned glass tooth crown is attached to this, and its circumference is the outer diameter of the abutment.
The material was placed over the i-layer and placed in an electric furnace, heated to 700° C. at a rate of 300° C./hour, and kept at that temperature for 4 hours to effect crystallization. After crystallization, the crown was easily removed from the abutment.

The borrowed tooth crown was found to be uniformly crystallized, no unevenness was observed in appearance, and the outer surface was flat 1'# and did not have the necessary V-shape of 5F. Matauchi @ was not shiny due to contact with Shifuga l,
There were no major irregularities.

The results of measuring the maximum diameter of the peripheral part of the tooth crown and measuring the dimensional change from the original model are shown in Figure 1. Clothes 1 also shows the compatibility and external appearance when the crown is placed on the abutment model.

Examples 2 to 7 Glass molded in the same manner as in Example 1 was crystallized in the same manner as in Example 1 on a refractory for an abutment.

Regarding the crowns after crystallization, dimensional changes in the maximum diameter of the periphery, compatibility with the abutment tooth model, and outer shell are shown in Precept 1.

Comparative Example A glass molded by casting in the same manner as in Example 1 was placed on a flat refractory made of wheat excavated from the investment material, and heat treated in the same manner as in Example 1.

Although the obtained crystallized glass had a uniform and smooth surface, the shape was completely deformed and it was impossible to fit it into the original masonry model.

The physical properties of this material are also shown in Table 1.

Claims (1)

[Claims] 1. The inner surface of calcium phosphate glass cast in the shape of a tooth crown is attached so as to be in close contact with the outer surface of a refractory that is shaped like an abutment tooth and does not deform at temperatures below 800°C. A method for producing a calcium phosphate-based crystallized glass tooth crown, which comprises performing crystallization. 2. The refractory is one in which aggregates of silica, alumina, and zircon are bound by a gypsum-based, ethyl silicate-based, magnesium phosphate-based, or aluminum phosphate binder, or hard gypsum. Production method. 3. Calcium phosphate glass contains 70% by weight or more of calcium phosphate and has a Ca/P atomic ratio of 0.35.
The manufacturing method according to claim (1), having a composition of ˜0.7.