CA2170084A1 - Use of gold alloys for precision attachments in dental technology - Google Patents
Use of gold alloys for precision attachments in dental technologyInfo
- Publication number
- CA2170084A1 CA2170084A1 CA002170084A CA2170084A CA2170084A1 CA 2170084 A1 CA2170084 A1 CA 2170084A1 CA 002170084 A CA002170084 A CA 002170084A CA 2170084 A CA2170084 A CA 2170084A CA 2170084 A1 CA2170084 A1 CA 2170084A1
- Authority
- CA
- Canada
- Prior art keywords
- alloys
- gold
- attachments
- precision
- precision attachments
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K6/00—Preparations for dentistry
- A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
- A61K6/84—Preparations for artificial teeth, for filling teeth or for capping teeth comprising metals or alloys
- A61K6/844—Noble metals
Abstract
Alloys for precision attachments in dental technology with improved mechanical properties, improved corrosion resistance and golden-yellow colour consist of gold with 1.2 to 2.3 wt.% titanium.
Description
- 217008~
Use of gold alloys for precision attachments in dental technology 5 Description:
The invention relates to the use of gold alloys as material for precision attachments in dental technology.
Precision connecting elements, such as for example attachments or joints, are frequently used as so-called precision attachments especially in the manufacture of removable dental appliances. Such precision attachments are nowadays usually offered in prefabricated form. By 15 reason of the individual problems, numerous different constructions exist. Thus, already in 1989 about 290 different systems were on the market. A large number of different alloys based on noble metals are used for their manufacture.
These precision attachments are usually very expensive to fabricate. This is due to the smallness of the parts, which is coupled with complicated geometries and close tolerances in order to withstand the high demands in 25 clinical use. In addition, by reason of the high strength requirements, high-strength alloys must be used, which as a rule have difficult forming behaviour, owing to the elevated hardness. Usually only those alloys are used which have Vickers hardnesses above 200 and yield points of 30 more than 450 MPa.
In addition, high requirements are set for these alloys with regard to the corrosion resistance, in order to guarantee the biocompatibility of corresponding dental - ~170084 constructions. In this connection the requirements with regard to corrosion resistance are more likely to have to be rated higher than in the case of cast dental appliances, since in the case of precision attachments, crevices, for example between the attachment surfaces, are unavoidable.
All preconditions for a situation of intensified corrosion by crevice corrosion are thereby met. An optimum bio-compatibility is obtained by the use of alloys of the highest resistance to corrosion, for which the least 10 possible alloying elements suffice.
The precision attachments are fastened to the parts of the prosthesis by brazing or by direct casting-on of the dental alloy to the precision attachments. For these precision 15 attachments, alloys are required that contain no base metal, so that during the preheating before the casting-on, no interfering oxide layer is formed which would prevent a bond of self-substance between precision attachments and dental alloy. The compositions of these alloys are usually 20 based on gold-platinum-palladium or also platinum-iridium.
Especially high-strength alloys of this type are described for example in DE-PS 35 42 641.
Especially in the case of yellow dental alloy systems capable of being fused to, which can be veneered with special low-melting ceramics, precision attachments of yellow alloys are desirable, in order that these do not stand out in colour from the base material. These yellow alloys have previously all been alloyed with base metals and so are not capable of being cast on. Their composition is generally based on gold-platinum-silver-copper and they owe their mechanical strength largely to the silver-copper miscibility gap. As a result of the relatively high proportion of copper required thereby, there is potentially 2170Q8~
a tendency to discoloration, especially when a crevice corrosion situation exists. Recently, therefore, the goal has been pursued of further reducing the copper content of these alloys. In order to be able to guarantee high 5 mechanical strengths, further steps of alloy technology are required, which, though, result in a reduction of the ductility and, accompanying this, a still greater fabrication expenditure.
It was therefore the object of the present invention to discover gold alloys for precision attachments in dental technology, which have a golden yellow colour and are sufficiently hard and well formable. They should also be extremely corrosion-resistant, have an optimum bio-15 compatibility, and therefore have no toxically questionableconstituents.
This object is achieved according to the invention by the use of gold alloys with 1.2 to 2.3 wt.% titanium, the remainder being gold.
Preferably, alloys are used that contain 1.6 to 1.8 wt.%
titanium, the remainder being gold.
Surprisingly, alloys can be produced on the basis of gold with titanium additions of 1.2 to 2.3 wt.% which have a considerably more favorable forming and corrosion behaviour than the previously-known alloys for constructional elements. The high reactivity of the element titanium can 30 be controlled as regards melt technology by melting under inert gas in suitable crucibles. Binary alloys of gold and 1.6 to 1.8 wt.% titanium, which have optimum properties with regard to colour and corrosion resistance as well as forming behaviour, have especially proved their worth.
217008~
Listed in Table 1 by way of example are three yellow alloys of the conventional type of alloy (alloys 1 to 3) in addition to some alloys according to the invention (alloys 4 to 6). The accompanying mechanical characteristic data can be found in Table 2.
- 2l7aos4 ~ -Table 1: Alloy compositions (wt.~) Alloy Au Ag Pt Pd Cu Zn In Ti Other 1 13 111.5 Ir 0.1 65.5 8.9 0.5 2 9 - 4.4 2 1.5 Ir 0.1 73.8 9.2 3 Zr 3.0 97.0 4 1.4 Ir 0.1 98.6 1.7 98.3 6 2.1 97.9 Table 2: Mechanical characteristic data HV-H HV-W Rp-H Rp-W A-W A-H (%) Alloy (MPa) (MPa) (~) 3 23090 600 247 21 <1 HV-H: Vickers hardness in hard condition (optimum heat treatment temperature in each case) HV-W: Vickers hardness in soft condition (quenched in water) Rp-H: Yield point in hard condition ~170D8~
Rp-W: Yield point in soft condition A-H: Ductility for hard condition in tensile test (technical elongation) A-W: Ductility for soft condition in tensile test (technical elongation) While in the hard condition the known alloys and the alloys according to the invention have no serious differences in the mechanical characteristic data, in the soft-annealed state the alloys according to the invention have clearly better values. The hardness values, in contrast to the conventional alloys, can fall considerably further, in some cases to only about one-third of the values that the conventional alloys possess. This is accompanied by a large reduction of the yield point and a massive rise of the ductility to values of about 60 ~. Both the rise of the ductility and the clear reduction of hardness and yield point lead to a striking improvement of the forming behaviour. As a result of the higher ductility, greater 20 degrees of deformation and a reduction of the number of intermediate annealings can be achieved and as a result of the lower strength, lower deformation forces are required.
Both factors together lead to clearly reduced fabrication costs and times and also permit novel, more efficient fabrication methods, as for example impact extrusion.
After the deformation processes, high strengths and lower ductilities can again be set through suitable heat treatments. From now on the hard state has a very favourable behaviour during subsequent shape cutting. In the use as precision attachments also the high strengths are again necessary.
Surprisingly, these alloys have also proved to be distinguished by an extraordinary corrosion resistance.
~170084 The characteristic data on corrosion resistance are assembled in Table 3. The corrosion resistance was determined according to DIN E 13927 in a one-week immersion test in 0.1 molar lactic acid - common salt solution on the 5 basis of the liberated corrosion products. Listed in Table 3 are the totals of the liberated corrosion products per cm2 of sample surface. The investigations were carried out once on samples with freshly ground surface and once on samples that were subsequently subjected to a heat treatment in addition. An ageing of 1 h at 500 C in air was selected in each case as heat treatment. In this heat treatment the alloys according to the invention reach the highest strengths. Such a treatment may therefore be carried out after the last shaping. While with the 15 conventional alloys, the corrosion rate rises as a result, so that the annealing must be carried out under inert gas, this annealing treatment surprisingly leads in the case of the alloys according to the invention to a further improvement of the corrosion resistance. In the case of the binary alloys, the corrosion rate even sinks below the limit of detection Alloy Total corrosion rate Total corrosion rate (~g/cm2) of ground (~g/cm2) after additional surface heat treatment 0.3 <DL*
Use of gold alloys for precision attachments in dental technology 5 Description:
The invention relates to the use of gold alloys as material for precision attachments in dental technology.
Precision connecting elements, such as for example attachments or joints, are frequently used as so-called precision attachments especially in the manufacture of removable dental appliances. Such precision attachments are nowadays usually offered in prefabricated form. By 15 reason of the individual problems, numerous different constructions exist. Thus, already in 1989 about 290 different systems were on the market. A large number of different alloys based on noble metals are used for their manufacture.
These precision attachments are usually very expensive to fabricate. This is due to the smallness of the parts, which is coupled with complicated geometries and close tolerances in order to withstand the high demands in 25 clinical use. In addition, by reason of the high strength requirements, high-strength alloys must be used, which as a rule have difficult forming behaviour, owing to the elevated hardness. Usually only those alloys are used which have Vickers hardnesses above 200 and yield points of 30 more than 450 MPa.
In addition, high requirements are set for these alloys with regard to the corrosion resistance, in order to guarantee the biocompatibility of corresponding dental - ~170084 constructions. In this connection the requirements with regard to corrosion resistance are more likely to have to be rated higher than in the case of cast dental appliances, since in the case of precision attachments, crevices, for example between the attachment surfaces, are unavoidable.
All preconditions for a situation of intensified corrosion by crevice corrosion are thereby met. An optimum bio-compatibility is obtained by the use of alloys of the highest resistance to corrosion, for which the least 10 possible alloying elements suffice.
The precision attachments are fastened to the parts of the prosthesis by brazing or by direct casting-on of the dental alloy to the precision attachments. For these precision 15 attachments, alloys are required that contain no base metal, so that during the preheating before the casting-on, no interfering oxide layer is formed which would prevent a bond of self-substance between precision attachments and dental alloy. The compositions of these alloys are usually 20 based on gold-platinum-palladium or also platinum-iridium.
Especially high-strength alloys of this type are described for example in DE-PS 35 42 641.
Especially in the case of yellow dental alloy systems capable of being fused to, which can be veneered with special low-melting ceramics, precision attachments of yellow alloys are desirable, in order that these do not stand out in colour from the base material. These yellow alloys have previously all been alloyed with base metals and so are not capable of being cast on. Their composition is generally based on gold-platinum-silver-copper and they owe their mechanical strength largely to the silver-copper miscibility gap. As a result of the relatively high proportion of copper required thereby, there is potentially 2170Q8~
a tendency to discoloration, especially when a crevice corrosion situation exists. Recently, therefore, the goal has been pursued of further reducing the copper content of these alloys. In order to be able to guarantee high 5 mechanical strengths, further steps of alloy technology are required, which, though, result in a reduction of the ductility and, accompanying this, a still greater fabrication expenditure.
It was therefore the object of the present invention to discover gold alloys for precision attachments in dental technology, which have a golden yellow colour and are sufficiently hard and well formable. They should also be extremely corrosion-resistant, have an optimum bio-15 compatibility, and therefore have no toxically questionableconstituents.
This object is achieved according to the invention by the use of gold alloys with 1.2 to 2.3 wt.% titanium, the remainder being gold.
Preferably, alloys are used that contain 1.6 to 1.8 wt.%
titanium, the remainder being gold.
Surprisingly, alloys can be produced on the basis of gold with titanium additions of 1.2 to 2.3 wt.% which have a considerably more favorable forming and corrosion behaviour than the previously-known alloys for constructional elements. The high reactivity of the element titanium can 30 be controlled as regards melt technology by melting under inert gas in suitable crucibles. Binary alloys of gold and 1.6 to 1.8 wt.% titanium, which have optimum properties with regard to colour and corrosion resistance as well as forming behaviour, have especially proved their worth.
217008~
Listed in Table 1 by way of example are three yellow alloys of the conventional type of alloy (alloys 1 to 3) in addition to some alloys according to the invention (alloys 4 to 6). The accompanying mechanical characteristic data can be found in Table 2.
- 2l7aos4 ~ -Table 1: Alloy compositions (wt.~) Alloy Au Ag Pt Pd Cu Zn In Ti Other 1 13 111.5 Ir 0.1 65.5 8.9 0.5 2 9 - 4.4 2 1.5 Ir 0.1 73.8 9.2 3 Zr 3.0 97.0 4 1.4 Ir 0.1 98.6 1.7 98.3 6 2.1 97.9 Table 2: Mechanical characteristic data HV-H HV-W Rp-H Rp-W A-W A-H (%) Alloy (MPa) (MPa) (~) 3 23090 600 247 21 <1 HV-H: Vickers hardness in hard condition (optimum heat treatment temperature in each case) HV-W: Vickers hardness in soft condition (quenched in water) Rp-H: Yield point in hard condition ~170D8~
Rp-W: Yield point in soft condition A-H: Ductility for hard condition in tensile test (technical elongation) A-W: Ductility for soft condition in tensile test (technical elongation) While in the hard condition the known alloys and the alloys according to the invention have no serious differences in the mechanical characteristic data, in the soft-annealed state the alloys according to the invention have clearly better values. The hardness values, in contrast to the conventional alloys, can fall considerably further, in some cases to only about one-third of the values that the conventional alloys possess. This is accompanied by a large reduction of the yield point and a massive rise of the ductility to values of about 60 ~. Both the rise of the ductility and the clear reduction of hardness and yield point lead to a striking improvement of the forming behaviour. As a result of the higher ductility, greater 20 degrees of deformation and a reduction of the number of intermediate annealings can be achieved and as a result of the lower strength, lower deformation forces are required.
Both factors together lead to clearly reduced fabrication costs and times and also permit novel, more efficient fabrication methods, as for example impact extrusion.
After the deformation processes, high strengths and lower ductilities can again be set through suitable heat treatments. From now on the hard state has a very favourable behaviour during subsequent shape cutting. In the use as precision attachments also the high strengths are again necessary.
Surprisingly, these alloys have also proved to be distinguished by an extraordinary corrosion resistance.
~170084 The characteristic data on corrosion resistance are assembled in Table 3. The corrosion resistance was determined according to DIN E 13927 in a one-week immersion test in 0.1 molar lactic acid - common salt solution on the 5 basis of the liberated corrosion products. Listed in Table 3 are the totals of the liberated corrosion products per cm2 of sample surface. The investigations were carried out once on samples with freshly ground surface and once on samples that were subsequently subjected to a heat treatment in addition. An ageing of 1 h at 500 C in air was selected in each case as heat treatment. In this heat treatment the alloys according to the invention reach the highest strengths. Such a treatment may therefore be carried out after the last shaping. While with the 15 conventional alloys, the corrosion rate rises as a result, so that the annealing must be carried out under inert gas, this annealing treatment surprisingly leads in the case of the alloys according to the invention to a further improvement of the corrosion resistance. In the case of the binary alloys, the corrosion rate even sinks below the limit of detection Alloy Total corrosion rate Total corrosion rate (~g/cm2) of ground (~g/cm2) after additional surface heat treatment 0.3 <DL*
6 0.5 <DL*
* DL = detection limit = 0.13 ~g/cm2 - ~170084 The following examples are intended to illustrate the alloys according to the invention in more detail:
S 1. For the manufacture of an attachment, an initial material with a rectangular cross-section of 3.3 x 6 mm must be produced from a continuously cast cylindrical rod of 9 mm diameter. For alloy 1 (Table 1), 8 intermediate annealings as well as 9 reduction passes followed by 3 drawing steps are required.
For alloy 2 (Table 1), 11 intermediate annealings as well as 10 reduction passes followed by 3 drawing steps are required for this.
The alloys nos. 5 and 6 according to the invention (Table 1), on the other hand, require only 3 or 4 intermediate annealings respectively as well as 6 reduction passes followed by 3 drawing steps. The fabrication of the initial material is therefore considerably less time-consuming.
2. For the manufacture of a cylindrical root pin, conventional alloys are machined on a lathe. With the alloy no. 6 according to the invention, on the other hand, a wire of appropriate diameter, after previous soft annealing, can be pressed directly by means of an impact extrusion operation into a final shape. For this application a finishing operation is not required.
* DL = detection limit = 0.13 ~g/cm2 - ~170084 The following examples are intended to illustrate the alloys according to the invention in more detail:
S 1. For the manufacture of an attachment, an initial material with a rectangular cross-section of 3.3 x 6 mm must be produced from a continuously cast cylindrical rod of 9 mm diameter. For alloy 1 (Table 1), 8 intermediate annealings as well as 9 reduction passes followed by 3 drawing steps are required.
For alloy 2 (Table 1), 11 intermediate annealings as well as 10 reduction passes followed by 3 drawing steps are required for this.
The alloys nos. 5 and 6 according to the invention (Table 1), on the other hand, require only 3 or 4 intermediate annealings respectively as well as 6 reduction passes followed by 3 drawing steps. The fabrication of the initial material is therefore considerably less time-consuming.
2. For the manufacture of a cylindrical root pin, conventional alloys are machined on a lathe. With the alloy no. 6 according to the invention, on the other hand, a wire of appropriate diameter, after previous soft annealing, can be pressed directly by means of an impact extrusion operation into a final shape. For this application a finishing operation is not required.
Claims (2)
1. The use of gold alloys with 1.2 to 2.3 wt.% titanium, the remainder being gold, as material for precision attachments in dental technology.
2. The use of an alloy according to Claim 1, characterized in that it contains 1.6 to 1.8 wt.%
titanium, the remainder being gold.
titanium, the remainder being gold.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19506680.4 | 1995-02-25 | ||
| DE19506680 | 1995-02-25 | ||
| DE19604827.3 | 1996-02-12 | ||
| DE19604827A DE19604827C2 (en) | 1995-02-25 | 1996-02-12 | Use of gold alloys for construction elements in dental technology |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2170084A1 true CA2170084A1 (en) | 1996-08-26 |
Family
ID=26012825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002170084A Abandoned CA2170084A1 (en) | 1995-02-25 | 1996-02-22 | Use of gold alloys for precision attachments in dental technology |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0729740B1 (en) |
| JP (1) | JPH08260076A (en) |
| AT (1) | ATE262307T1 (en) |
| CA (1) | CA2170084A1 (en) |
| DK (1) | DK0729740T3 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19604827C2 (en) * | 1995-02-25 | 1997-03-06 | Degussa | Use of gold alloys for construction elements in dental technology |
| DE19718308C2 (en) * | 1997-04-30 | 2001-05-23 | Juergen Kosper | Method for testing the bond strength of metal-ceramic systems |
| US7279054B2 (en) | 2004-05-14 | 2007-10-09 | The Argen Corporation | Dental prosthesis method and alloys |
| JP6288917B2 (en) * | 2013-02-18 | 2018-03-07 | 石福金属興業株式会社 | Dental casting alloy and method for producing the same |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4306542A1 (en) * | 1993-01-14 | 1994-07-21 | Sunder Plassmann Paul Dr | Gold@-titanium@ alloys used for dental restoration work |
| DE4419408C1 (en) * | 1994-06-03 | 1995-07-06 | Wieland Edelmetalle | Gold@ dental alloy contg. titanium and other named hypoallergenic additives |
| ES2110725T5 (en) * | 1994-07-05 | 2002-02-01 | Cendres & Metaux Sa | DENTAL ALLOY WITH HIGH GOLD CONTENT. |
-
1996
- 1996-02-20 EP EP96102504A patent/EP0729740B1/en not_active Expired - Lifetime
- 1996-02-20 AT AT96102504T patent/ATE262307T1/en not_active IP Right Cessation
- 1996-02-20 DK DK96102504T patent/DK0729740T3/en active
- 1996-02-22 CA CA002170084A patent/CA2170084A1/en not_active Abandoned
- 1996-02-26 JP JP3766596A patent/JPH08260076A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ATE262307T1 (en) | 2004-04-15 |
| EP0729740A3 (en) | 2000-03-29 |
| EP0729740B1 (en) | 2004-03-24 |
| DK0729740T3 (en) | 2004-07-26 |
| JPH08260076A (en) | 1996-10-08 |
| EP0729740A2 (en) | 1996-09-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |