DE2514672A1 - PROSTHETIC ITEMS AND MATERIALS SUITABLE FOR THEM - Google Patents

Description

concerning

Prosthetic items and suitable therefor

material

Prosthetic items, especially those for dental

and
technology, must be firmly corrosion-resistant, have a good appearance and be compatible with living tissue ·. In addition, the material must be easily malleable.

Metallic materials used in dental technology must also be able to be coated with an inorganic oxide such as porcelain. So that this is possible "the metallic material must have a compatible surface oxide film on its top *. A compatible oxide coating leads to a connection with the melted inorganic oxide coating, which is applied later. Alloys for dental technology must also have a coefficient of thermal expansion that is not too different from the fused inorganic oxide coating, otherwise the various temperature changes during the application and melting of one or more layers of inorganic oxides will result in cracking of the layer and a Chipping can occur when the thermal expansion is too different between the oxide and the metal.

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So far, precious metals have been used in dental technology, in particular Gold. The high cost of gold increases unnecessary-

and tooth repair

wise the cost of dentures. In addition, the low Gold tensile strength unsatisfactory in some respects. Although there is a slight layer of porcelain on gold can be applied, you often need your own binding layer, as the natural oxide layer is not in each Respect for the binding of porcelain is sufficient. It goes without saying that it is forbidden for large prosthetic objects to as for hip joints, the application of gold because of the high price.

Dental alloys made from base metals are already known. These consist primarily of nickel and also contain beryllium as an alloying element (US Pat. No. 3,749,570). Although this alloy has satisfactory physical properties, both in the manufacture of the Alloy as well as difficulties in the manufacture of the objects because of the high loxicity of beryllium. the Processing of such alloys for the prosthetic objects must be carried out under extreme protective conditions so that vapors, dust or other forms of the alloy or their compounds are used by the personnel involved neither inhaled nor ingested. Especially in small laboratories, such as in dental technology, it is extraordinary difficult, if not impossible, to adhere to appropriate safety measures for such a hazardous material. Even with adequate security equipment available, it is difficult to ensure that everyone in • Sufficiently inform the laboratories employed are about the dangers of processing beryllium alloys and about the use of safety devices,

The invention avoids or largely mitigates all of the above problems. Ifaoh the invention consist of the prosthetic items made of niobium precious metal alloys, which have a natural

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Form oxide coating that is not only compatible with the usual in dental technology: applied molten inorganic Oxides, but effectively participates in the bond between these fused oxides and the metallic body. The expansion and contraction of the alloy as a result of temperature changes corresponds so largely the expansion and contraction of the molten inorganic oxide deduction that in this one Cracking is avoided. The alloy does not contain any highly toxic products, so you can use them without special precautions melt, pour, polish or otherwise process.

Here, "prosthetic objects" are understood to mean a metal object that is used in a living being direct contact with living tissue to replace a missing part or to repair a malfunctioning one Part. Prosthetic objects can be simple metal inserts such as dental fillings; however, they can also be very be much more complex, such as dental crowns, bridges, plates or implants for bones of the leg, for jawbones or like «. The term" molten inorganic oxide " refers to a substance made of an inorganic oxide which changes its physical form at high temperature Has. Examples of this are porcelain coatings or a glassy material such as those used in dental technology. The term "bone tissue" refers to a hard bone-like tissue and also includes tissue types as in US Pat Teeth. The term “bonded” here means a fixation on a surface without the use of an interposed one Binding material such as an organic cement.

The alloys according to the invention contain 12 to 20% chromium, 7 to 12% cobalt, 1.5 to 5 % molybdenum, tungsten, mob and / or tantalum, 5 to 9 # aluminum and / or titanium, 0.05 to 0, 2 # carbon, 0.005 to 0.1 # boron, 0.05 to 0 * 2 $ zirconium and / or hafnium, the remainder nickel. Processing the alloy

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is generally done by melting in the air and pouring, after which, if necessary, full or partial Coating with a melted inorganic oxide, which is bound to the surface, take place can. The shaping of the object is done with a view to the place of application. The alloy is extremely compatible not only with bone tissue to which it is attached, but also with soft tissue with which it comes into contact. So can use a tooth crown made of the alloy according to the invention a porcelain cover can be worn comfortably without limitation. Neither the porcelain nor the alloy react adversely with the tooth or the gum. The alloy is sufficiently corrosion resistant that it will with the body fluids there is no corrosion. It resists the galvanic effects of various metals, as found in the Mouth. For example, a person can have a crown made of the above alloys according to the invention together with a gold filling in another tooth and a silver amalgam filling in another tooth without becoming one galvanic reaction occurs between the crown and the metals, whereby any of the metals would or would be destroyed complaints would arise.

The alloy according to the invention must contain the above components. However, it can also contain other substances. A particularly suitable alloy, which is commercially available, contains 15 to 18 fo chromium, 8 to 11 fo cobalt, 0.75 to 2.2 fo molybdenum, 1.8 to 3 fo tungsten, 0.5 to 2 fo niob, 1 to 3 fo tantalum, 3 to 4 fo aluminum, 0.1 to 2 fo carbon, 3 to 4 fo titanium, 0.01 to 0.05 fo boron, 0.01 to 0.2 fo zirconium, balance nickel (US -PS 3 459 545). This alloy has been used for turbine blades in gas turbines.

The alloys can be processed in any of the techniques commonly used for prosthetic objects, especially in dental technology. The first stage consists in forming the alloy by melting and casting on the air. The casting has a thin oxide layer that is dense and

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firmly adheres to the metal and is compatible with the melted, inorganic oxides, which are generally used for these purposes. In the case of the melted inorganic Oxides are primarily silicon dioxide and aluminum oxide and various compounds of the Silicon and aluminum with oxygen. Photomicrographs of the bond between the alloys and such materials as Dental porcelain, show that the bond does not occur at a sharp interface between the porcelain and the metal oxide layer, but that the natural oxide layer of the metal mixes with the melted inorganic oxides forming a deep bond that has a compositional gradient from the metal surface to the Shows coating of molten inorganic oxide. It is noteworthy that this deep bond, what a special one Compatibility between the melted inorganic Oxides and the metal oxide layer shows the cause is for the extremely strong bond that the coating of the invention alloy with melted inorganic

Oxides are permitted which do not crack when exposed to temperature changes or chipped even if subjected to pressure or abrasion.

The molten inorganic oxides can be vitrified, such as dental porcelain, or they can be porous, such as biscuit porcelain. Molten dental porcelain can be multilayered applied in _(usually "Thus one can, for example, the metallic shaped body as a prosthetic object is first coated with an opaque layer to cover the metal, after which comes a porcelain layer, and finally followed by a vitreous enamel layer, then the natural translucent tooth-like Appearance.

Should the metallic prosthetic object be directly ia Bone tissue are implanted, so it is preferably coated with bisque. Biscuit porcelain is compatible with living tissue and is sufficiently porous for a 3? aser-

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Tissue that can grow into the pores, creating a firm connection between bone tissue and the prosthetic object. Thus, one can produce an artificial hip joint characterized, for example, that the part _(the connected to the thigh bone _{is coated with bisque. A nail from such an alloy is not only compatible with the bone tissue, but also allows the ingrowth of fibrous bone tissue in the Pores of the biscuit porcelain, whereby a very strong connection is formed. Such parts of dental material which are implanted directly into the jawbone are also preferably coated with bisque porcelain.

The following example explains the invention and is directed to the production of a tooth crown. This exists from the alloy according to the invention. The outer part of the tooth crown is covered with dental porcelain.

A wax model of the crown is made in the usual way. This is used in the usual way for the production of the mold (high-heat oxy-phosphate investment). A corresponding wax insert is provided for the casting. The wax is then ausgeschmolzen- in about 30 minutes at about 37o C ⁰ and the residue in 1 h burned at 870 G ^0. The mold thus obtained is mounted on a conventional centrifugal casting machine.

With the help of an acetylene fan, an alloy of 16 <? ° Or, 10 # Co, 2 % Mo, 2.5 $ W, 1 % Nb, 1.25 1 » IDa, 3.5 $ Al, 3, 5 f ° Ti, 0.18 fo C, 0.02 $ B, 0.1 % Zr and 59.95 i> Ni melted down. A blower is used with an oxygen pressure of 0.7 atmospheres and an acetylene pressure of 0.56. The melting point of the alloy is about 134O ⁰ C. sink down a little when the alloy mixture begins, a casting flux is added. If the temperature rises a little, the alloy becomes thin and forms

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a ball in the crucible. When the alloy is runny, it is poured into the porm.

After solidification and cooling, it is removed from the mold and if necessary the casting is cleaned, after which it is blasted with fine sand. Covers can be turned down to 0.1 to 0.2 mm will. This is about half the strength required for dental gold alloys,

The areas to be coated with porcelain are finely sanded, the others polished if necessary. The castings are carefully rubbed with ammonium hydroxide and dried. No degassing or acid treatment is required, to make the surfaces receptive to the porcelain. Commonly used and commercially available Porcelain and glassy materials are applied and processed according to the delivery regulations. All commercially available Dental porcelains are compatible with the castings and lead to stronger bonds than when the previous ones were used Dental alloys. After the porcelain work is finished, the porcelain is coated with a soft wax and the crown sandblasted and polished. Usual polishing techniques are used; the alloy has an excellent shine, which can be seen in the relevant technology called "high micron luster". It resists corrosion and the formation of tartar. the The crown is then assembled as usual.

Claims

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Claims (2)

Claims 1. Prosthetic objects made of a nickel alloy containing 12 to 20 chromium fo, fo 7 to 12 cobalt, 1.5 to 5 f> molybdenum, tungsten, niobium and / or tantalum, 5 to 9 fo aluminum and / or titanium, 0, 05 to 0.2 fo carbon, 0.005 to 0.1 f> boron, 0.05 to 0.2 fo zirconium and / or hafnium, balance nickel, optionally with a layer of molten inorganic oxide. 2. Prosthetic article according to claim 1, characterized by a nickel alloy containing 15 to 18 fo Gr, 8 to 11 fo Co, 0.75 to 2.2 fo Mo, 1.8 to 3 ^ ¥, 0.5 to 2 f »Nb, 1 to 3 fo Ta, 3 to 4 fo Al, 0.1 to 0.2 fo G, 3 to 4 fo Ti, the total content of nickel and titanium not exceeding 7.5 fo, 0.01 up to 0.5 $> B, 0.01 to 0.2 fo Zr, the remainder essentially nickel. 3 · Prosthetic article according to claim 1 or 2, there marked by that the melted inorganic oxides dental porcelain or bisque porcelain sindo 4o material for the production of the objects according to claims 1 to 3 in ΙΌπα a nickel alloy, containing 12 Ms 20 fo Cr, 7 to 12 fo Co, 1.5 to 5 fo Mo, ¥, Nb and / or 5 to 9 fo Al and / or Ti, 0.05 to 0.2 fo C, 0.005 to 0.1 B, 0.05 to 0.2 fo Zr and / or Hf, the remainder being nickel. 8143 509846/1052