JPS6055127B2 - Dental prosthetic crown baking table - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a firing table for firing a porcelain welded and cast crown (hereinafter referred to as a prosthetic crown) of a dental prosthesis.

Prosthetic crowns are fired at high temperatures several times before they are completed.

As an example, the case of four firings is shown below. 1st time...
...Baking of opaque porcelain to mask the color of metal (600-9600) 6 minutes 2nd session...Baking of crown-colored porcelain (600-9300) 6 minutes 3rd session ...Correction baking for porcelain shrinkage (600-9600) 6 minutes Fig. 4...Crayzink (glossy firing) (800-9
600) 4 minutes As shown in Fig. 6, the conventional firing table has a support pin that is set up on the firing table and a prosthetic crown is placed on the tip of the support pin, which is tapered so that it fits into the firing table. Because of this, the position of the tip remains constant, and it is impossible to adjust it to match the prosthetic crown.

Therefore, up to a single crown or a three-tooth bridge with one missing tooth can be used without any problems, but when firing a long bridge with multiple missing teeth, several support pins are used; In many cases, the tip touches the deepest part of the inner cavity of the prosthetic crown, creating a gap S, and is not supported. If high-temperature heating is repeated several times as described above in this state, a portion of the gap S will sag and become distorted due to the weight of the prosthetic crown.

In addition, conventional firing tables do not take into account the thermal expansion coefficient, so when firing a long prosthetic crown with multiple teeth at high temperature, the thermal expansion of the prosthetic crown and the firing table that supports it are different, so the prosthesis The problem was that the crown could crack or become distorted, making it impossible to produce a prosthetic crown that required extremely high precision.

The purpose of this invention is to obtain a high-precision product that does not cause cracking or distortion even with such long prosthetic crowns, and this firing table can also be used as a solder to connect prosthetic crowns. We are trying to make it possible to use it as well.
Hereinafter, the present invention will be explained based on the accompanying drawings.

The firing table 1 for planting the base of the elongated support pin that supports the prosthetic crown by covering the tip thereof can be shaped into a horseshoe shape as shown in FIG. 1, an oval shape as shown in FIG. 2, an arc shape as shown in the third diagram, etc. A plurality of small holes 2 or long holes 3 are provided in the plate surface. Further, legs 4 are provided at appropriate positions on the back surface, and can be placed on a workbench as is for work, or can be used for positioning when placed on a pedestal 9, which will be described later. Reference numerals 6, 6a, and 6b are support pins, which are used to insert the lower end into the small hole 2 or long hole 3 of the firing table 1, and to support it by covering the tip with the prosthetic crown 7, as shown in Fig. 5. Examples of shapes include the straight one (6) shown in Figure 4, the one with a flange (6a), and the one bent at the position where it hits the firing table (6b) with the top and bottom eccentric. It is desirable that the coefficient of expansion is the same as that of dental metal or similar to that of dental metal as much as possible.

The tips of the support pins 6, 6a, and 6b are sharpened so that they can easily enter the narrowest part of the inner cavity of the prosthetic crown 7. In addition, the area near the lower end is either shaved off a little or made into a square shape to prevent rotation when fixed with the investment material 8. The support pin 6 is straight and can be freely adjusted in vertical height. Similarly, the support pin 6a has a flange, and the flange hits the firing table to receive the support pin. Moreover, if it is made non-circular, the investment material 8
When solidified, it also serves to prevent rotation.

Similarly, 6b is bent at the position where it hits the firing table so that the upper and lower parts are eccentric, and when the lower part is inserted into the firing table 1, the bending becomes the upper and lower positioning, and the eccentricity is used to align the teeth of the prosthetic crown 7. It is designed to be rotated to adjust the position. Support pins 6 with various shapes like these,
Prepare a large number of 6a and 6b and choose the appropriate one! There are things to use.

The firing table 1 is made of a metal or ceramic whose expansion coefficient is the same as or similar to that of the metal for the prosthetic crown 7. For example, a nickel-chromium alloy is often used as the prosthetic crown metal; The coefficient of thermal expansion is 12 x 101/°C to 13 x 10-6/°C, and if you make a baking table from the same material, you will get a metal baking table with exactly the same coefficient of thermal expansion. .

In addition, in order to manufacture a ceramic firing table, alumina (AI2O
3), a suitable mixture of forsterite (2Mg0-SiO2), magnesium oxide (MgO), titanium oxide (TiO.), etc. is used, and its thermal expansion coefficient is 12×
The coefficient of thermal expansion is 101/°C to 13×101/°C, which is almost the same as the coefficient of thermal expansion of the prosthetic crown metal. In addition, a single ceramic may be used, and in that case, the coefficient of thermal expansion of the ceramic used is as follows, so choose one that approximates the coefficient of thermal expansion of the prosthetic crown metal. .

Thermal expansion coefficient of ceramics Alumina (Al2O3
) 7×10-6/℃ forsterite (Y
gOISiO2) 10×1
0-6/℃ Titanium oxide (TlO2) 11×1
0-6/℃ Magnesium oxide (MgO) 14×10
-6/°C Next, how to use this baking table will be explained.

Prosthetic crown 7 about to be fired with firing table 1 placed on the work table
Select the support pins 6, 6a, and 6b to match, temporarily insert their lower ends into the small holes 2 and elongated holes 3 of the firing table 1, cover the prosthetic crown 7, and then hold the prosthetic crown 7 with one hand and hold it with the other hand. Grasp the firing table 1 and place the prosthetic crown 7 on the table upside down.
Place baking table 1 upside down and support it with your hands if necessary. In this way, two or at most three of the several support pins, either the flanged support pins 6a or the bent support pins 6b, will touch the flanges or bent portions to the firing table 1, and
The tip is in contact with the deepest part of the inner cavity of the prosthetic crown 7, and the other support pins are lowered by their own weight, and the tips are in contact with the deepest part of the inner cavity of the prosthetic crown 7. That is, if the support pin 6 is straight, it will descend as it is, but if the support pin 6a has a flange or the support pin 6b is bent, the flange or the bent portion will move away from the baking table 1 and then descend. In this state, the support pins 6, 6 protruding from the back of the firing table facing upward
Apply investment material 8 to cover the legs of a and 6b. Leave this as it is for 2 to 3 minutes, and when the investment material hardens a little, gently lift the firing table 1, turn it upside down, return it to its normal state, place it on the workbench, and leave it for a while, and the investment material will harden. Once the support pins 6, 6a, and 6b are fixed, the investment material 8 is applied to the base of the support pin from the front side, and left as is for a while to wait for the investment material to completely harden. In this way, as shown in FIG. 5, after fixing the bases of the support pins 6, 6a, and 6b that are planted from both the front and back sides of the firing table 1, when the prosthetic crown 7 is again placed over the tips of the support pins, all the support pins are fixed. The tip of the prosthetic crown 7 is in contact with the innermost part of the prosthetic crown 7 without any gap.

Another method for applying the tips of the support pins 6, 6a, and 6b to the deepest part of the inner cavity of the prosthetic crown is to use a pedestal 9 shown in FIG. Fill with the investment material 8, place the firing table 1 on it, and attach the support pins 6, 6a, 6 as confirmed in advance according to the prosthetic crown 7.
After temporarily inserting the prosthetic crown 7 shallowly and standing it up, adjust the position of the support pin while covering the tip with the prosthetic crown 7. When the adjustment is completed, push down the prosthetic crown 7 with a little force, and all the support pins 6,
The tips of 6a and 6b hit the innermost part of the prosthetic crown 7 and push the lower end of the support pin into the investment material 8.

This state is maintained for a while, and once the investment material 8 has hardened, the investment material 8 is also applied to the base of the support pin on the top surface of the firing table, and after the investment material 8 has hardened, the pedestal 9 is removed. .

When this pedestal 9 is used, it is not necessary to turn over the baking table when applying the investment material for fixing the base of the support pin, so the work becomes very easy. Investment material 8 is usually 20
It is completely naturally hardened with ~3 powders, and when hardening is completed, the baking table 1 and the support pins 6, 6a, 6b are fixed together, and the support pins are not attached to the scraped part at the lower end or the non-circular shape. The flange, eccentric bent portion, etc. are buried in the investment material 8, so that rotation is completely prevented.

With the prosthetic crown 7 supported on the tips of the support pins 6, 6a, and 6b, the baking table 1 is placed in an electric furnace and the above-described baking is performed.

This firing table can also be used as a solder for connecting several prosthetic crowns 7, and the investment material 8 is also filled in the inner cavity of the prosthetic crown 7 to connect the tips of the support pins 6, 6a, 6b. Since the prosthetic crown 7 and the firing table 1 are fixed together, the prosthetic crown 7 and the firing table 1 can be soldered together in the same manner as firing, keeping the prosthetic crown 7 in the furnace at an appropriate temperature for soldering.

When firing or soldering is completed as described above, the investment material 8 is removed and the firing table 1 and support pins 6, 6a, 6
This is to organize the items b in preparation for the next use.

When the firing table according to the present invention is used, the expansion coefficients of the prosthetic crown and firing table are set to the same or similar values, and the prosthetic crown is completely supported, so that cracks and distortions due to expansion and contraction do not occur. It also functions as an excellent baking table, as it does not sag due to its own weight, produces products with extremely high precision, and is easy to work with.

Note that the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

The attached drawings show examples of the present invention, and FIG. 1, FIG. 2, and FIG. 3 show examples of firing tables with different shapes.
The figure shows a horseshoe-shaped one, Fig. 2 shows an oval-shaped one, Fig. 3 is a perspective view showing an arc-shaped one, and Fig. 4 is a perspective view showing three types of support pins. Figure 5 shows the one with a flange, C shows the one with an eccentric gate, Figure 5 is an enlarged expanded sectional view showing the prosthetic crown supported and in use, and Figure 6 shows the conventional firing table in the same usage condition. A developed enlarged cross-sectional view showing
FIG. 7 is a sectional view taken along the line AB in FIG. 5, and FIG. 8 is a perspective view of a pedestal for a horseshoe-shaped baking table. 1... Baking stand, 2... Small hole, 3...
...long hole, 4...leg, 6, 6a, 6b...
...Support pin, 7...Prosthetic crown, 8...
- Investment material, 9... pedestal, 10... recessed part.

Claims (1)

[Claims] 1. A baking table for a dental prosthetic crown consisting of a support pin that supports a metal dental prosthetic crown and a baking table into which the support pin is fitted, wherein the baking table has a coefficient of thermal expansion of 12×10^-
A baking table for a dental prosthetic crown, characterized in that the temperature is ^6/°C to 13 x 10^-^6/°C.