JPS60214718A - Dental restored matter - 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 The present invention relates to a dental restoration using a castable dental alloy that exhibits a stable golden color.

Precious metal alloys applied in ceramic bonding (application as porcelain jackets or coverings) are well known in dentistry and are used for crowns, bridges, other prosthetic devices and for replacing missing or missing teeth. Reconstruction (r
estoratlon). These so-called ceramic alloys typically contain about g[theta]-9[theta]% gold, relatively large amounts of platinum (j-/!i%) and radium (7-10%). For information on this type of alloy and its use in professional dentistry, see Wagner &
It is discussed in detail in Wagner & Pralow, US Pat. No. 3,'/-/3,723.

One problem with known alloys is that they have a tendency to take on a somewhat silver or white gold-like appearance, but the ideal ceramic alloy would not be suitable for the repeated casting and application of opaque porcelain materials. It should still have a stable true golden color after several firing cycles. The golden color is particularly desired to match the shade of all adjacent crowns, as most patients find this color to be more esthetically and cosmetically satisfying.

As a result of intensive research to solve these problems, the present signer has found that porcelain has a stable golden color that retains even after being fired on a cast alloy, and that it can be combined with dental porcelain. Completed a suitable castable dental alloy (JP-A-Shoj+-/θ0
923). That is, about 1 in the alloy! ;-3. 0
wt. % of rhodium, it has been found that a surprisingly true and stable golden color can be obtained.

Small amounts of rhodium (less than ajwt-%) have previously been used for the purpose of grain refinement (gra+n-re++n+ng) in alloys, but such amounts of the element were insufficient to obtain a stable gold color. . Another important factor is to limit the copper content of the alloy to less than lθwta%.

It has been found that the use of excessive amounts of copper causes severe oxidation when the alloy is cast and has an adverse effect on the integrity and color of the porcelain.

The alloy used in the present invention consists of 3 to 7 g of gold, 7 to 2 g of platinum, and i! -3.0%, up to 10% copper (the weight ratio of Rozocum to steel is preferably in the range of 3 to 1S), and further contains elements for grain refinement and formation of bond oxides. The currently preferred alloy composition is 3% gold and 9% platinum by weight. ! i%, rhodium. 2.0 chi, copper 0. j%, silver l3%, indium 0.5'%
, tin 0. S%, and Iridium/22%. The present invention contemplates a method of manufacturing a dental restoration by baking a porcelain jacket onto a portion of a cast body of an alloy having the above properties.

The golden porcelain alloy used in the present invention has the following elemental components (% is by weight).

Element Preferred composition (%) Tolerance range (%) Gold T! g3~g platinum Gold 9.3 7~/2 0dium Uθ lS-3 Copper θ5 Silver below lθ l3 Indium below weak θ 0, , t, 2. 0 or less Tin 0. ! r
Iridium up to l5 0.2 Iron up to 1 theta Ruthenium up to a3 Ruthenium up to IO Rhenium up to l theta This alloy has a melting point in the range of about /10 theta C and is described in US Pat. It has bonding properties and a coefficient of thermal expansion that are well matched to porcelain jacket materials of the type specified in No. 4T/3, No. 23. The alloy is Guita. VNa Zahn-jabrlk
Dental porcelain available under the trade name VM-16T was tested and found to be satisfactory. Other compatible porcelain materials include DentsplyInt@r
Natlonal, Inc. (under the trade name "Bobond") and Ceramco.

The Ceramco Dlvlslon Jo
hnson & johnson).

The preferred alloy casting body is! 2. Ultimate tensile strength at θ00 psl, 35! Yield strength C0 of θθθpsi (2% offset), elongation of 12%, Vickers hardness of 1lIO,
and/2. The binding strength of θ00p1 is shown.

Strength and elongation were measured with an Instron tensile tester, and Vickers hardness was measured with a microhardness tester equipped with a diamond prince. The strength of the porcelain bond to the cast alloy body is determined by Hiroshi/Journal, Otsu, Dental, Research (Journal
of Dental Research) / '12
'The shell (,h
ell) and the Wielson technique.

After casting, the preferred alloy has a rich golden color, and this color is stable and retained during repeated cycles of firing the porcelain layer on the body of the cast alloy. The oxides formed on the porcelain jacket have the highly desirable property that they do not discolor the porcelain jacket.

The resulting restoration has a porcelain surface that can be adjusted to match the appearance of adjacent teeth, as well as an exposed alloy surface with a true gold color that matches the patient's daytime gold crown or other gold restoration. ing.

Platinum is used in alloys to provide increased strength and to control melting points. Platinum also contributes to the color of the alloy, but excessive amounts of this metal lend the alloy an overly silvery cast. Copper also contributes to the strength and color control of the alloy, but
The amount must be limited to avoid severe oxidation. Preferably, the weight ratio of rhodium to copper is kept within the range of about 3 to 3/3.

This relatively high rhodium content is believed to be the dominant factor in providing a true golden color that remains stable over repeated porcelain firing cycles. Relatively high contents of indium (as used in conventional alloys)
(up to 3%) are not used in the new alloy of the present invention to avoid silver coloration in the cast restoration.

Indium and tin are included in the alloy to ensure the formation of bonding oxides required for proper adhesion of the porcelain material. Seventh of iridium, ruthenium and rhenium
The primary function is grain refinement, and the iron (if necessary) contributes to the hardness and strength of the alloy. The preferred proportion of rhodium (2 wt, %) gives good color as well as good color stability, higher proportions to rhodium are usually not used in view of the relatively high price of this element.

In use, the alloy is cast into the desired prosthetic shape using conventional investment casting techniques. A porcelain layer (usually including one or more opaque layers) is then fired onto the cast alloy body using known porcelain firing techniques.

The outstanding feature of this alloy is that it retains the structural properties and cohesive properties of traditional ceramic alloys, while retaining its attractive and solid golden color - even after such firing cycles. . A number of different alloys were tested to arrive at a preferred formulation or acceptable composition range. Typical examples of these alloys are shown below (components are given in weight percent):
gg /2.0 1t, 0 rhodium 13 λ, 23
．． θ 10 Steel C3l left 70 3.0 Silver 13 13 13 13 Indium lθ C3C3C3 Copper 0.5 θ Shio C3C3 Iridium 0.2 0. The alloy of k θ/ θ/Example/ was blended with rhodium at approximately the lower limit of the allowable range. Although this alloy exhibited a beautiful golden color after casting, it was only marginally acceptable in terms of color stability after repeated porcelain firing cycles. Alloy oxides formed during the firing cycle showed no tendency to discolor the porcelain jacket.

The example alloy was intentionally formulated with an excess of q, which was found to discolor the porcelain jacket. This alloy, however, exhibited good initial color after casting, and the color was stable over repeated firing cycles.

The alloys of Examples 3 and 3 were also unsatisfactory in that the oxides in both formulations caused discoloration of the porcelain jacket.

The alloy of Example 3 had a good initial golden color after casting, but the color faded during porcelain firing. The alloy of Example D had a silvery color with a golden background after casting, and after firing of the porcelain layer, the color faded to white gold. Both rows 3 and 3 have a fairly low total content, and in this case the rhodium content is low and the copper content is high.

Claims (1)

[Claims] l g 3 to g 7 wt-% gold, 7 to / 2 wt
-% platinum, 1S - 3wt, % rhodium, 7wt - multi-base steel, the weight ratio of rhodium to steel is in the range 3 to 1S, further containing elements for grain refinement and formation of bond oxides A dental restoration consisting of a castable dental alloy formed into a cast body for intraoral installation, and a porcelain jacket further fired over the body. Is the alloy worth 33~g of gold? wt-% platinum 7~/, l wt, % T2dium l3~3wt, % copper/wt, silver below wt-polymer group indium wt-polymer group tin IA; wt-polymer group iridium/ 2. The dental restoration of claim 1, consisting essentially of less than 0.5 wt iron, less than 05 wt, less than % ruthenium/wt, less than % rhenium/wt, % or less. The alloy is gold g wt-% platinum 9 k wt8% rhodium wt-% @0. ! % silver 13 wt, % indium (7,j wt-% tin o, 5 vtt, % iridium 0.!; wt, %) Dental restoration according to claim 1.